<PAGE>
 
Exhibit 4.1

                        HOUSTON LIGHTING & POWER COMPANY

                                       to

                              THE BANK OF NEW YORK,

                                     Trustee

              ----------------------------------------------------

                          JUNIOR SUBORDINATED INDENTURE

                        Dated as of ____________ 1, 1997

              ----------------------------------------------------
<PAGE>
 
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                                TABLE OF CONTENTS

                                                                                     Page
                                    ARTICLE I

DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION
  <S>             <C>                                                                 <C> 
  SECTION 1.1.    Definitions........................................................  1
  SECTION 1.2.    Compliance Certificate and
                  Opinions........................................................... 11
  SECTION 1.3.    Forms of Documents Delivered to
                  Trustee............................................................ 12
  SECTION 1.4.    Acts of Holders.................................................... 13
  SECTION 1.5.    Notices, Etc. to Trustee and
                  Company............................................................ 15
  SECTION 1.6.    Notice to Holders; Waiver.......................................... 16
  SECTION 1.7.    Conflict with Trust Indenture Act.................................. 16
  SECTION 1.8.    Effect of Headings and Table of
                  Contents........................................................... 16
  SECTION 1.9.    Successors and Assigns............................................. 16
  SECTION 1.10.   Separability Clause................................................ 16
  SECTION 1.11.   Benefits of Indenture.............................................. 17
  SECTION 1.12.   Governing Law...................................................... 17
  SECTION 1.13.   Non-Business Days.................................................. 17

                                   ARTICLE II

                                 SECURITY FORMS

  SECTION 2.1.    Forms Generally....................................................  17
  SECTION 2.2.    Form of Face of Security...........................................  18
  SECTION 2.3.    Form of Reverse of Security........................................  22
  SECTION 2.4.    Additional Provisions Required in                                    
                  Global Security....................................................  25
  SECTION 2.5.    Form of Trustee's Certificate of                                     
                  Authentication.....................................................  26

                                   ARTICLE III

                                 THE SECURITIES

  SECTION 3.1.    Title and Terms.................................................... 26
  SECTION 3.2.    Denominations...................................................... 29
  SECTION 3.3.    Execution, Authentication, Delivery
                  and Dating......................................................... 29
  SECTION 3.4.    Temporary Securities............................................... 31
  SECTION 3.5.    Registration, Transfer and Exchange................................ 31
  SECTION 3.6.    Mutilated, Destroyed, Lost and
                  Stolen Securities.................................................. 34
  SECTION 3.7.    Payment of Interest; Interest
                  Rights Preserved................................................... 35
  SECTION 3.8.    Persons Deemed Owners.............................................. 37
  SECTION 3.9.    Cancellation....................................................... 37
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                                       i
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  <S>             <C>                                                                 <C> 
  SECTION 3.10.   Computation of Interest............................................ 37
  SECTION 3.11.   Deferrals of Interest Payment
                  Dates.............................................................. 37
  SECTION 3.12.   Right of Set-Off................................................... 39
  SECTION 3.13.   Agreed Tax Treatment............................................... 39
  SECTION 3.14.   Advancing or Extension of Stated
                  Maturity........................................................... 39
  SECTION 3.15.   CUSIP Numbers...................................................... 40

                                  ARTICLE IV

                          SATISFACTION AND DISCHARGE

  SECTION 4.1.    Satisfaction and Discharge of
                  Indenture.......................................................... 40
  SECTION 4.2.    Application of Trust Money......................................... 42

                                    ARTICLE V

                                    REMEDIES

  SECTION 5.1.    Events of Default.................................................. 42
  SECTION 5.2.    Acceleration of Maturity;
                  Rescission and Annulment........................................... 43
  SECTION 5.3.    Collection of Indebtedness and
                  Suits for Enforcement by Trustee................................... 45
  SECTION 5.4.    Trustee May File Proofs of Claim................................... 46
  SECTION 5.5.    Trustee May Enforce Claims Without
                  Possession of Securities........................................... 47
  SECTION 5.6.    Application of Money Collected..................................... 47
  SECTION 5.7.    Limitation on Suits................................................ 48
  SECTION 5.8.    Unconditional Right of Holders to
                  Receive Principal, Premium and
                  Interest; Direct Action by Holders
                  of Preference Securities........................................... 49
  SECTION 5.9.    Restoration of Rights and Remedies................................. 49
  SECTION 5.10.   Rights and Remedies Cumulative..................................... 49
  SECTION 5.11.   Delay or Omission Not Waiver....................................... 50
  SECTION 5.12.   Control by Holders................................................. 50
  SECTION 5.13.   Waiver of Past Defaults............................................ 50
  SECTION 5.14.   Undertaking for Costs.............................................. 51
  SECTION 5.15.   Waiver of Usury, Stay or Extension
                  Laws............................................................... 51

                                   ARTICLE VI

                                   THE TRUSTEE

  SECTION 6.1.    Certain Duties and
                  Responsibilities................................................... 52
  SECTION 6.2.    Notice of Defaults................................................. 53
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                                ii
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  <S>             <C>                                                                 <C> 
  SECTION 6.3.    Certain Rights of Trustee.......................................... 54
  SECTION 6.4.    Not Responsible for Recitals or
                  Issuance of Securities............................................. 55
  SECTION 6.5.    May Hold Securities................................................ 55
  SECTION 6.6.    Money Held in Trust................................................ 55
  SECTION 6.7.    Compensation and Reimbursement..................................... 55
  SECTION 6.8.    Disqualification; Conflicting
                  Interests.......................................................... 56
  SECTION 6.9.    Corporate Trustee Required;
                  Eligibility........................................................ 56
  SECTION 6.10.   Resignation and Removal;
                  Appointment of Successor........................................... 57
  SECTION 6.11.   Acceptance of Appointment by
                  Successor.......................................................... 59
  SECTION 6.12.   Merger, Conversion, Consolidation
                  or Succession to Business.......................................... 60
  SECTION 6.13.   Preferential Collection of Claims
                  Against Company.................................................... 61
  SECTION 6.14.   Appointment of Authenticating
                  Agent.............................................................. 61

                                   ARTICLE VII

                HOLDER'S LISTS AND REPORTS BY TRUSTEE AND COMPANY

  SECTION 7.1.    Company to Furnish Trustee Names
                  and Addresses of Holders........................................... 63
  SECTION 7.2.    Preservation of Information,
                  Communications to Holders.......................................... 63
  SECTION 7.3.    Reports by Trustee................................................. 64
  SECTION 7.4.    Reports by Company................................................. 64

                                  ARTICLE VIII

              CONSOLIDATION, MERGER, CONVEYANCE, TRANSFER OR LEASE

  SECTION 8.1.    Company May Consolidate, Etc., Only
                  on Certain Terms................................................... 65
  SECTION 8.2.    Successor Corporation Substituted.................................. 66

                                   ARTICLE IX

                             SUPPLEMENTAL INDENTURES

  SECTION 9.1.    Supplemental Indentures without
                  Consent of Holders................................................. 67
  SECTION 9.2.    Supplemental Indentures with
                  Consent of Holders................................................. 68
  SECTION 9.3.    Execution of Supplemental
                  Indentures......................................................... 70
  SECTION 9.4.    Effect of Supplemental Indentures.................................. 70
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                                iii
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  <S>             <C>                                                                 <C> 
  SECTION 9.5.    Conformity with Trust Indenture
                  Act................................................................ 70
  SECTION 9.6.    Reference in Securities to
                  Supplemental Indentures............................................ 70

                                   ARTICLE X

                                   COVENANTS

  SECTION 10.1.   Payment of Principal, Premium and
                  Interest........................................................... 71
  SECTION 10.2.   Maintenance of Office or Agency.................................... 71
  SECTION 10.3.   Money for Security Payments to be
                  Held in Trust...................................................... 72
  SECTION 10.4.   Statement as to Compliance......................................... 73
  SECTION 10.5.   Waiver of Certain Covenants........................................ 74
  SECTION 10.6.   Additional Sums.................................................... 74
  SECTION 10.7.   Additional Covenants............................................... 75
  SECTION 10.8.   Calculation of Original Issue Discount............................. 75

                                   ARTICLE XI

                            REDEMPTION OF SECURITIES

  SECTION 11.1.   Applicability of This Article...................................... 76
  SECTION 11.2.   Election to Redeem; Notice to
                  Trustee............................................................ 76
  SECTION 11.3.   Selection of Securities to be
                  Redeemed........................................................... 77
  SECTION 11.4.   Notice of Redemption............................................... 77
  SECTION 11.5.   Deposit of Redemption Price........................................ 78
  SECTION 11.6.   Payment of Securities Called for
                  Redemption......................................................... 78

                                   ARTICLE XII

                                  SINKING FUNDS

  SECTION 12.1.   Applicability of Article........................................... 79
  SECTION 12.2.   Satisfaction of Sinking Fund
                  Payments with Securities........................................... 80
  SECTION 12.3.   Redemption of Securities for
                  Sinking Fund....................................................... 80

                                  ARTICLE XIII

                           SUBORDINATION OF SECURITIES

  SECTION 13.1.   Securities Subordinate to Senior
                  Debt............................................................... 82
  SECTION 13.2.   Payment Over of Proceeds Upon
                  Dissolution, Etc................................................... 82
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                                iv
<PAGE>
 
                                                                            Page

SECTION 13.3.  Prior Payment to Senior Debt Upon Acceleration of 
               Securities..................................................   84
SECTION 13.4.  No Payment When Senior Debt in Default......................   85
SECTION 13.5.  Obligations of Company Unconditional........................   86
SECTION 13.6.  Subrogation to Rights of Holders of Senior Debt.............   87
SECTION 13.7.  Provisions Solely to Define Relative Rights.................   88
SECTION 13.8.  Trustee to Effectuate Subordination.........................   88
SECTION 13.9.  No Waiver of Subordination Provisions.......................   88
SECTION 13.10. Notice to Trustee...........................................   89
SECTION 13.11. Reliance on Judicial Order or Certificate of Liquidating    
               Agent.......................................................   90
SECTION 13.12. Trustee Not Fiduciary for Holders of Senior Debt............   90
SECTION 13.13. Rights of Trustee as Holder of Senior Debt; Preservation 
               of Trustee's Rights.........................................   90
SECTION 13.14. Article Applicable to Paying Agents.........................   91
SECTION 13.15. Certain Conversions or Exchanges Deemed Payment.............   91

                                       v
<PAGE>
 
                        HOUSTON LIGHTING & POWER COMPANY

          Reconciliation and tie between the Trust Indenture Act of 1939
(including cross-references to provisions of Sections 310 to and including 317
which, pursuant to Section 318(c) of the Trust Indenture Act of 1939, as amended
by the Trust Reform Act of 1990, are a part of and govern the Indenture whether
or not physically contained therein) and the Junior Subordinated Indenture,
dated as of __________ 1, 1997.

Trust Indenture

Act Section                                                      Section
-----------------                                                ---------------
(S) 310 (a)(1), (2) and (5)....................................  6.9
        (a)(3).................................................  Not Applicable
        (a)(4).................................................  Not Applicable
        (b)....................................................  6.8, 6.10
        (c)....................................................  Not Applicable
(S) 311 (a)....................................................  6.13
        (b)(4).................................................  6.13(a)
        (b)(6).................................................  6.13(b)
(S) 312 (a)....................................................  7.1, 7.2(a)
        (b)....................................................  7.2(b)
        (c)....................................................  7.2(c)
(S) 313 (a)....................................................  7.3(a), 7.3(b)
        (c)....................................................  7.3(a)
        (d)....................................................  7.3(c)
(S) 314 (a)(1), (2), (3) and (4)...............................  7.4
        (b)....................................................  Not Applicable
        (c)(1) and (2).........................................  1.2
        (c)(3).................................................  Not Applicable
        (d)....................................................  Not Applicable
        (e)....................................................  1.2
(S) 315 (a)....................................................  6.1(a)
        (b)....................................................  6.2
        (c)....................................................  6.1(b)
        (d)(1).................................................  6.1(c)(1)
        (d)(2).................................................  6.1(c)(2)
        (d)(3).................................................  6.1(c)(3)
        (e)....................................................  5.14
(S) 316 (a)(1)(A)..............................................  5.12
        (a)(1)(B)..............................................  5.13
        (a)(2).................................................  Not Applicable
        (b)....................................................  5.8
        (c)....................................................  1.4(f)
(S) 317 (a)(1).................................................  5.3
        (a)(2).................................................  5.4
        (b)....................................................  10.3
(S) 318 (a)....................................................  1.7


----------------
Note:  This reconciliation and tie shall not, for any purpose, be deemed to be a
       part of the Junior Subordinated Indenture.

                                       vi
<PAGE>
 
       JUNIOR SUBORDINATED INDENTURE, dated as of [__________ 1], 1997, between
HOUSTON LIGHTING & POWER COMPANY, a Texas corporation (hereinafter called the
"Company") having its principal office at Houston Industries Plaza, 1111
Louisiana, Houston, Texas 77002, and The Bank of New York, a New York banking
corporation, as Trustee (hereinafter called the "Trustee").


                            RECITALS OF THE COMPANY

       The Company has duly authorized the execution and delivery of this
Indenture to provide for the issuance from time to time of its unsecured junior
subordinated debt securities in series (hereinafter called the "Securities") of
substantially the tenor hereinafter provided, including, without limitation,
Securities issued to evidence loans made to the Company of the proceeds from the
issuance from time to time by one or more business trusts (each an "HL&P Trust,"
and, collectively, the "HL&P Trusts") of beneficial interests in such Trusts
(such interests to be called either "Preferred Securities" or "Capital
Securities" and, collectively, the "Preference Securities") and common interests
in such Trusts (the "Common Securities" and, collectively with the Preference
Securities, the "Trust Securities"), and to provide the terms and conditions
upon which the Securities are to be authenticated, issued and delivered.

       All things necessary to make the Securities, when executed by the Company
and authenticated and delivered hereunder and duly issued by the Company, the
valid obligations of the Company, and to make this Indenture a valid agreement
of the Company, in accordance with their and its terms, have been done.

       NOW THEREFORE, THIS INDENTURE WITNESSETH:  For and in consideration of
the premises and the purchase of the Securities by the Holders thereof, it is
mutually covenanted and agreed, for the equal and proportionate benefit of all
Holders of the Securities or of any series thereof, as follows:


                                   ARTICLE I

            DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION

       SECTION 1.1.   Definitions.

       For all purposes of this Indenture, except as otherwise expressly
provided or unless the context otherwise requires:
<PAGE>
 
       (1) The terms defined in this Article have the meanings assigned to them
in this Article, and include the plural as well as the singular;

       (2) All other terms used herein which are defined in the Trust Indenture
Act, either directly or by reference therein, have the meanings assigned to them
therein;

       (3) All accounting terms not otherwise defined herein have the meanings
assigned to them in accordance with generally accepted accounting principles,
and the term "generally accepted accounting principles" with respect to any
computation required or permitted hereunder shall mean such accounting
principles which are generally accepted at the date or time of such computation;
provided, that when two or more principles are so generally accepted, it shall
mean that set of principles consistent with those in use by the Company; and

       (4) The words "herein," "hereof" and "hereunder" and other words of
similar import refer to this Indenture as a whole and not to any particular
Article, Section or other subdivision.

       "Act" when used with respect to any Holder has the meaning specified in
Section 1.4.

       "Additional Interest" means the interest, if any, that shall accrue on
any interest on the Securities of any series the payment of which has not been
made on the applicable Interest Payment Date and which shall accrue at the rate
per annum specified or determined as specified in such Security. Additional 
Interest will accrue under the circumstances contemplated under this Indenture, 
to the extent permitted by applicable law.

       "Additional Sums" has the meaning specified in Section 10.6.

       "Additional Taxes" means the sum of any additional taxes, duties and
other governmental charges to which an HL&P Trust has become subject from time
to time as a result of a Tax Event.

       "Administrative Trustee" means, in respect of any HL&P Trust, each Person
identified as an "Administrative Trustee" in the related Trust Agreement, solely
in such Person's capacity as Administrative Trustee of such HL&P Trust under
such Trust Agreement and not in such Person's individual capacity, or any
successor administrative trustee appointed as therein provided.

       "Affiliate" of any specified Person means any other Person directly or
indirectly controlling or controlled by or under direct or indirect common
control with such specified

                                       2
<PAGE>
 
Person; provided, however, no HL&P Trust to which Securities have been issued
shall be deemed to be an Affiliate of the Company.  For the purposes of this
definition, "control" when used with respect to any specified Person means the
power to direct the management and policies of such Person, directly or
indirectly, whether through the ownership of voting securities, by contract or
otherwise; and the terms "controlling" and "controlled" have meanings
correlative to the foregoing.

       "Authenticating Agent" means any Person authorized by the Trustee
pursuant to Section 6.14 to act on behalf of the Trustee to authenticate
Securities of one or more series.

       "Board of Directors" means either the board of directors of the Company
or any committee of that board duly authorized to act hereunder.

       "Board Resolution" means a copy of a resolution certified by the
Secretary or an Assistant Secretary of the Company to have been duly adopted by
the Board of Directors, or such committee of the Board of Directors or officers
of the Company to which authority to act on behalf of the Board of Directors has
been delegated, and to be in full force and effect on the date of such
certification, and delivered to the Trustee.

       "Business Day" means any day other than (i) a Saturday or Sunday, (ii) a
day on which banking institutions in The City of New York are authorized or
required by law or executive order to remain closed or (iii) a day on which the
Corporate Trust Office of the Trustee, or, with respect to the Securities of a
series initially issued to an HL&P Trust, the principal corporate trust office
of the Property Trustee under the related Trust Agreement, is closed for
business.

       "Capital Securities" has the meaning specified in the first recital of
this Indenture.

       "Commission" means the Securities and Exchange Commission, as from time
to time constituted, created under the Exchange Act, or if at any time after the
execution of this instrument such Commission is not existing and performing the
duties now assigned to it under the Trust Indenture Act, then the body
performing such duties at such time.

       "Common Securities" has the meaning specified in the first recital of
this Indenture.

       "Common Stock" means the common stock of the Company.


                                       3
<PAGE>
 
       "Company" means the Person named as the "Company" in the first paragraph
of this instrument until a successor Person shall have become such pursuant to
the applicable provisions of this Indenture, and thereafter "Company" shall mean
such successor Person.

       "Company Agent" means any officer of Houston Industries, the parent 
company of the Company, who is authorized and empowered pursuant to one or more 
Board Resolutions to negotiate, execute and deliver on behalf of the Company 
instruments, certificates and documents in connection with the Company's 
financing activities including, without limitation, the President, any Vice 
President, the Treasurer, the Secretary, and Assistant Secretary or any 
Assistant Treasurer of Houston Industries.

       "Company Request" and "Company Order" mean, respectively, the written
request or order signed in the name of the Company by the Chairman of the Board
of Directors, any Vice Chairman of the Board of Directors, its President or a
Vice President, and by its Treasurer, an Assistant Treasurer, its Secretary or
an Assistant Secretary of the Company or a Company Agent, and delivered to the
Trustee.

       "Corporate Trust Office" means the principal office of the Trustee at
which at any particular time its corporate trust business shall be administered,
which at the date hereof is 101 Barclay Street, Floor 21 West, New York, New
York 10286. Attention: Corporate Trust Trustee Administrator.

       "corporation" includes a corporation, association, company, joint-stock
company or business trust.

       "Debt" means, with respect to any Person, whether recourse is to all or a
portion of the assets of such Person and whether or not contingent, (i) every
obligation of such Person for money borrowed; (ii) every obligation of such
Person evidenced by bonds, debentures, notes or other similar instruments,
including obligations incurred in connection with the acquisition of property,
assets or businesses; (iii) every reimbursement obligation of such Person with
respect to letters of credit, bankers' acceptances or similar facilities issued
for the account of such Person; (iv) every obligation of such Person issued or
assumed as the deferred purchase price of property or services (but excluding
trade accounts payable or accrued liabilities arising in the ordinary course of
business); (v) every capital lease obligation of such Person; (vi) every
obligation of such Person for claims in respect of derivative products,
including interest rate, foreign exchange rate and commodity forward contracts,
options, swaps and similar arrangements; and (vii) every obligation of the type
referred to in clauses (i) through (vi) of another Person and all dividends of
another Person the payment of which, in either case, such Person has guaranteed
or is responsible or liable for, directly or indirectly, as obligor or
otherwise.

       "Defaulted Interest" has the meaning specified in Section 3.7.

       "Depositary" means, with respect to the Securities of any series issuable
or issued in whole or in part in the form of one or more Global Securities, the
Person designated as Depositary by the Company pursuant to Section 3.1 with
respect to such series (or any successor thereto).

                                       4
<PAGE>
 
       "Discount Security" means any security which provides for an amount less
than the principal amount thereof to be due and payable upon a declaration of
acceleration of the Maturity thereof pursuant to Section 5.2.

       "Distributions," with respect to the Trust Securities issued by an HL&P
Trust, means amounts payable in respect of such Trust Securities as provided in
the related Trust Agreement and referred to therein as "Distributions."

       "Dollar" means the currency of the United States of America that, as at
the time of payment, is legal tender for the payment of public and private
debts.

       "Event of Default" unless otherwise specified in the supplemental
indenture creating a series of Securities has the meaning specified in 
Article V.

       "Exchange Act" means the Securities Exchange Act of 1934 and any statute
successor thereto, in each case as amended from time to time.

       "Expiration Date" has the meaning specified in Section 1.4(f).

       "Extension Period" has the meaning specified in Section 3.11.

       "Global Security" means a Security in the form prescribed in Section 2.4
evidencing all or part of a series of Securities, issued to the Depository or
its nominee for such series, and registered in the name of such Depository or
its nominee.

       "Guarantee Agreement," with respect to an HL&P Trust, means the Guarantee
Agreement substantially in the form attached hereto as Annex D or Annex E, or
substantially in such form as may be specified as contemplated by Section 3.1
with respect to the Securities of any series, in each case as amended from time
to time.

       "HL&P Guarantee," with respect to an HL&P Trust, means the guarantee by
the Company of Distributions on the Preference Securities of such HL&P Trust to
the extent provided in the Guarantee Agreement with respect to such HL&P Trust.

       "HL&P Trust" has the meaning specified in the first recital of this
Indenture.

       "Holder" means a Person in whose name a Security is registered in the
Securities Register.

                                       5
<PAGE>
 
       "Houston Industries" means Houston Industries Incorporated, a Texas 
corporation.

       "Indenture" means this instrument as originally executed or as it may
from time to time be supplemented or amended by one or more indentures
supplemental hereto entered into pursuant to the applicable provisions hereof
and shall include the terms of each particular series of Securities established
as contemplated by Section 3.1.

       "Interest Payment Date" means as to each series of Securities the Stated
Maturity of an installment of interest on such Securities.

       "Investment Company Act Event" means the receipt by an HL&P Trust of an
Opinion of Counsel experienced in such matters to the effect that, as a result
of the occurrence of a change in law or regulation or a written change in
interpretation or application of law or regulation by any legislative body,
court, governmental agency or regulatory authority, there is more than an
insubstantial risk that such HL&P Trust is or will be considered an "investment
company" that is required to be registered under the Investment Company Act of
1940, as amended, which change becomes effective on or after the Original Issue
Date.

       "Junior Subordinated Payment" has the meaning specified in Section 13.2.

       "Maturity" when used with respect to any Security means the date on which
the principal of such Security becomes due and payable as therein or herein
provided, whether at the Stated Maturity or by declaration of acceleration, call
for redemption or otherwise.

       "Moody's" means Moody's Investors Service, Inc.

       "Notice of Default" means a written notice of the kind specified in
Section 5.1(3).

       "Officers' Certificate" means a certificate signed by the Chairman and
Chief Executive Officer, President or a Vice President, and by the Treasurer, an
Associate Treasurer, an Assistant Treasurer, the Controller, the Secretary or an
Assistant Secretary, of the Company, and delivered to the Trustee.

       "Opinion of Counsel" means a written opinion of counsel, who may be
counsel for the Company (and who may be an employee of the Company), and who
shall be acceptable to the Trustee.

       "Original Issue Date" means the date of issuance specified as such in
each Security.

       "Outstanding" means, when used in reference to any Securities, as of the
date of determination, all Securities

                                       6
<PAGE>
 
theretofore authenticated and delivered under this Indenture, except:

         (i)   Securities theretofore canceled by the Trustee or delivered to
the Trustee for cancellation;

        (ii)   Securities for whose payment money in the necessary amount has
been theretofore deposited with the Trustee or any Paying Agent in trust for the
Holders of such Securities; and

       (iii)   Securities in substitution for or in lieu of which other
Securities have been authenticated and delivered or which have been paid
pursuant to Section 3.6, unless proof satisfactory to the Trustee is presented
that any such Securities are held by Holders in whose hands such Securities are
valid, binding and legal obligations of the Company;

provided, however, that in determining whether the Holders of the requisite
principal amount of Outstanding Securities have given any request, demand,
authorization, direction, notice, consent or waiver hereunder, Securities owned
by the Company or any other obligor upon the Securities or any Affiliate of the
Company or such other obligor shall be disregarded and deemed not to be
Outstanding, except that, in determining whether the Trustee shall be protected
in relying upon any such request, demand, authorization, direction, notice,
consent or waiver, only Securities which a Responsible Officer of the Trustee
actually knows to be so owned shall be so disregarded.  Securities so owned
which have been pledged in good faith may be regarded as Outstanding if the
pledgee establishes to the satisfaction of the Trustee the pledgee's right so to
act with respect to such Securities and that the pledgee is not the Company or
any other obligor upon the Securities or any Affiliate of the Company or such
other obligor.  Upon the written request of the Trustee, the Company shall
furnish to the Trustee promptly an Officers' Certificate listing and identifying
all Securities, if any, known by the Company to be owned or held by or for the
account of the Company, or any other obligor on the Securities or any Affiliate
of the Company or such obligor, and, subject to the provisions of Section 6.1,
the Trustee shall be entitled to accept such Officers' Certificate as conclusive
evidence of the facts therein set forth and of the fact that all Securities not
listed therein are Outstanding for the purpose of any such determination.

       "Paying Agent" means the Trustee or any Person authorized by the Company
to pay the principal (and premium, if any) of or interest on any Securities on
behalf of the Company.

                                       7
<PAGE>
 
       "Person" means any individual, corporation, partnership, joint venture,
trust, unincorporated organization or government or any agency or political
subdivision thereof.

       "Place of Payment" means, with respect to the Securities of any series,
the place or places where the principal of (and premium, if any) and interest on
the Securities of such series are payable pursuant to Sections 3.1 and 3.11.

       "Predecessor Security" of any particular Security means every previous
Security evidencing all or a portion of the same debt as that evidenced by such
particular Security; and, for the purposes of this definition, any security
authenticated and delivered under Section 3.6 in lieu of a lost, destroyed or
stolen Security shall be deemed to evidence the same debt as the lost, destroyed
or stolen Security.

       "Preferred Securities" has the meaning specified in the first recital of
this Indenture.

       "Preference Securities" means the Preferred Securities and the Capital
Securities.

       "Proceeding" has the meaning specified in Section 13.2.

       "Property Trustee" means, in respect of any HL&P Trust, the commercial
bank or trust company identified as the "Property Trustee" in the related Trust
Agreement, solely in its capacity as Property Trustee of such HL&P Trust under
such Trust Agreement and not in its individual capacity, or its successor in
interest in such capacity, or any successor property trustee appointed as
therein provided.

       "Redemption Date," when used with respect to any Security to be redeemed,
means the date fixed for such redemption by or pursuant to this Indenture.

       "Redemption Price," when used with respect to any Security to be
redeemed, means the price at which it is to be redeemed pursuant to this
Indenture.

       "Regular Record Date" for the interest payable on any Interest Payment
Date with respect to the Securities of a series means, unless otherwise provided
pursuant to Section 3.1 with respect to Securities of a series, (i) in the case
of Securities of a series represented by one or more Global Securities, the
Business Day next preceding such Interest Payment Date and (ii) in the case of
Securities of a series not represented by one or more Global Securities, the
date which is fifteen days next preceding such Interest Payment Date (whether or
not a Business Day).

                                       8
<PAGE>
 
       "Responsible Officer" means, with respect to the Trustee, any Vice
President, any Assistant Vice President, any Assistant Secretary, the Treasurer,
any Assistant Treasurer, or any other officer of the Corporate Trust Office of
the Trustee and also means, with respect to a particular corporate trust matter,
any other officer to whom such matter is referred because of that officer's
knowledge of and familiarity with the particular subject.

       "Rights Plan" means a plan of the Company providing for the issuance by 
the Company to all holders of its Common Stock of rights entitling the holders 
thereof to subscribe for or purchase shares of Common Stock or any class or 
series of preferred stock or preference stock of the Company, which rights
(i) are deemed to be transferred with such shares of Common Stock, (ii) are not 
currently exercisable and (iii) are also issued in respect of future issuances
of Common Stock, in each case until the occurrence of a specified event or
events.

       "S&P" means Standard & Poor's Ratings Services.

       "Securities" or "Security" means any debt securities or debt security, as
the case may be, authenticated and delivered under this Indenture.

       "Securities Register" and "Securities Registrar" have the respective
meanings specified in Section 3.5.

       "Senior Debt" means the principal of (and premium, if any) and interest,
if any (including interest accruing on or after the filing of any petition in
bankruptcy or for reorganization relating to the Company whether or not such
claim for post-petition interest is allowed in such proceeding), on Debt of the
Company, whether incurred on or prior to the date of this Indenture or
thereafter incurred, unless, in the instrument creating or evidencing the same
or pursuant to which the same is outstanding, it is provided that such
obligations are not superior in right of payment to the Securities or to other
Debt which is pari passu with, or subordinated to, the Securities, provided,
however, that Senior Debt shall not be deemed to include (a) any Debt of the
Company which, when incurred and without respect to any election under Section
1111(b) of the Bankruptcy Reform Act of 1978, was without recourse to the
Company, (b) any Debt of the Company to any of its Subsidiaries, (c) Debt to any
employee of the Company, (d) Debt that by its terms is subordinated to trade
accounts payable or accrued liabilities arising in the ordinary course of
business to the extent that payments made to the holders of such Debt by the
holders of the Securities as a result of the subordination provisions of this
Indenture would be greater than such payments otherwise would have been (absent
giving effect to this clause (d)) as a result of any obligation of such holders
of such Debt to pay amounts over to the obligees on such trade accounts payable
or accrued liabilities arising in the ordinary course of business as a result of
subordination provisions to which such Debt is subject, and (e) any Securities;
provided further, however, with respect to Securities of a series initially
issued to an HL&P Trust which has a series of outstanding Preferred Securities,
Senior Debt shall include all Debt of the Company to any of its Subsidiaries.

       "Special Event" means an Investment Company Act Event or a Tax Event.

                                       9
<PAGE>
 
       "Special Record Date" for the payment of any Defaulted Interest means a
date fixed by the Trustee pursuant to Section 3.7.

       "Stated Maturity" when used with respect to any Security or any
installment of principal thereof or interest thereon means the date specified
pursuant to the terms of  such Security as the date on which the principal of
such Security or such installment of interest is due and payable, in the case of
such principal, as such date may be advanced or extended as provided pursuant to
the terms of such Security and this Indenture.

       "Subsidiary" means a corporation more than 50% of the outstanding voting
stock of which is owned, directly or indirectly, by the Company or by one or
more other Subsidiaries, or by the Company and one or more other Subsidiaries.
For purposes of this definition, "voting stock" means stock which ordinarily has
voting power for the election of directors, whether at all times or only so long
as no senior class of stock has such voting power by reason of any contingency.

       "Tax Event" means the receipt by an HL&P Trust of an Opinion of Counsel
experienced in such matters to the effect that, as a result of any amendment to,
or change (including any announced proposed change) in, the laws (or any
regulations thereunder) of the United States or any political subdivision or
taxing authority thereof or therein, or as a result of any official
administrative pronouncement or judicial decision interpreting or applying such
laws or regulations, which amendment or change is effective or which proposed
change, pronouncement or decision is announced on or after the date of issuance
of the Preference Securities of such HL&P Trust, there is more than an
insubstantial risk that (i) such HL&P Trust is, or will be within 90 days of the
date of such Opinion of Counsel, subject to United States Federal income tax
with respect to income received or accrued on the corresponding series of
Securities issued by the Company to such HL&P Trust, (ii) interest payable by
the Company on such corresponding series of Securities is not, or within 90 days
of the date of such Opinion of Counsel, will not be, deductible by the Company,
in whole or in part, for United States Federal income tax purposes or (iii) such
HL&P Trust is, or will be within 90 days of the date of such Opinion of Counsel,
subject to more than a de minimis amount of other taxes, duties or other
governmental charges.

       "Trust Agreement," with respect to an HL&P Trust, means a Trust Agreement
substantially in the form attached hereto as Annex A, as amended by the form of
Amended and Restated Trust Agreement substantially in the form attached hereto
as Annex B or Annex C, or substantially in such form as may be

                                      10
<PAGE>
 
specified as contemplated by Section 3.1 with respect to the Securities of any
series, in each case as amended from time to time.

       "Trustee" means the Person named as the "Trustee" in the first paragraph
of this instrument until a successor Trustee shall have become such pursuant to
the applicable provisions of this Indenture, and thereafter "Trustee" shall mean
or include each Person who is then a Trustee hereunder and, if at any time there
is more than one such Person, "Trustee" as used with respect to the Securities
of any series shall mean the Trustee with respect to Securities of that series.

       "Trust Indenture Act" means the Trust Indenture Act of 1939 (15 U.S.C.
(S)(S) 77aaa-77bbb), as amended and as in effect on the date as of this
Indenture, except as provided in Section 9.5.

       "Trust Securities" has the meaning specified in the first recital of this
Indenture.

       "Vice President" when used with respect to the Company, means any duly
appointed vice president, whether or not designated by a number or a word or
words added before or after the title "vice president."

       SECTION 1.2.   Compliance Certificate and Opinions.

       Upon any application or request by the Company to the Trustee to take any
action under any provision of this Indenture, the Company shall furnish to the
Trustee an Officers' Certificate stating that all conditions precedent
(including covenants, compliance with which constitutes a condition precedent),
if any, provided for in this Indenture relating to the proposed action have been
complied with and an Opinion of Counsel stating that in the opinion of such
counsel all such conditions precedent (including covenants compliance with which
constitute a condition precedent), if any, have been complied with, except that
in the case of any such application or request as to which the furnishing of
such documents is specifically required by any provision of this Indenture
relating to such particular application or request, no additional certificate or
opinion need be furnished.

       Every certificate or opinion with respect to compliance with a condition
or covenant provided for in this Indenture (other than the certificates provided
pursuant to Section 10.5) shall include:

       (1) a statement that each individual signing such certificate or opinion
has read such covenant or condition and the definitions herein relating thereto;

                                      11
<PAGE>
 
       (2) a brief statement as to the nature and scope of the examination or
investigation upon which the statements or opinions contained in such
certificate or opinion are based;

       (3) a statement that, in the opinion of each such individual, he has made
or caused to be made such examination or investigation as is necessary to enable
him to express an informed opinion as to whether or not such covenant or
condition has been complied with; and

       (4) a statement as to whether, in the opinion of each such individual,
such condition or covenant has been complied with.

       SECTION 1.3.   Forms of Documents Delivered to Trustee.

       In any case where several matters are required to be certified by, or
covered by an opinion of, any specified Person, it is not necessary that all
such matters be certified by, or covered by the opinion of, only one such
Person, or that they be so certified or covered by only one document, but one
such Person may certify or give an opinion with respect to some matters and one
or more other such Persons as to other matters, and any such Person may certify
or give an opinion as to such matters in one or several documents.

       Any certificate or opinion of an officer of the Company may be based,
insofar as it relates to legal matters, upon a certificate or opinion of, or
representations by, counsel, unless such officer or counsel knows, or in the
exercise of reasonable care should know, that the certificate or opinion or
representations with respect to the matters upon which his certificate or
opinion is based are erroneous.  Any such certificate or Opinion of Counsel may
be based, insofar as it relates to factual matters, upon a certificate or
opinion of, or representations by, an officer or officers of the Company stating
that the information with respect to such factual matters is in the possession
of the Company, unless such counsel knows, or in the exercise of reasonable care
should know, that the certificate or opinion or representations with respect to
such matters are erroneous.

       Where any Person is required to make, give or execute two or more
applications, requests, consents, certificates, statements, opinions, or other
instruments under this Indenture, they may, but need not, be consolidated and
form one instrument.


                                      12
<PAGE>
 
       SECTION 1.4.  Acts of Holders.

       (a) Any request, demand, authorization, direction, notice, consent,
waiver or other action provided by this Indenture to be given to or taken by
Holders may be embodied in and evidenced by one or more instruments of
substantially similar tenor signed by such Holders in person or by an agent duly
appointed in writing; and, except as herein otherwise expressly provided, such
action shall become effective when such instrument or instruments is or are
delivered to the Trustee, and, where it is hereby expressly required, to the
Company.  Such instrument or instruments (and the action embodied therein and
evidenced thereby) are herein sometimes referred to as the "Act" of the Holders
signing such instrument or instruments.  Proof of execution of any such
instrument or of a writing appointing any such agent shall be sufficient for any
purpose of this Indenture and (subject to Section 6.1) conclusive in favor of
the Trustee and the Company, if made in the manner provided in this Section.

       (b) The fact and date of the execution by any Person of any such
instrument or writing may be proved by the affidavit of a witness of such
execution or by the certificate of any notary public or other officer authorized
by law to take acknowledgments of deeds, certifying that the individual signing
such instrument or writing acknowledged to him the execution thereof.  Where
such execution is by a Person acting in other than his individual capacity, such
certificate or affidavit shall also constitute sufficient proof of his
authority.

       (c) The fact and date of the execution by any Person of any such
instrument or writing, or the authority of the Person executing the same, may
also be proved in any other manner which the Trustee deems sufficient and in
accordance with such reasonable rules as the Trustee may determine.

       (d) The ownership of Securities shall be proved by the Securities
Register.

       (e) Any request, demand, authorization, direction, notice, consent,
waiver or other action by the Holder of any Security shall bind every future
Holder of the same Security and the Holder of every Security issued upon the
transfer thereof or in exchange therefor or in lieu thereof in respect of
anything done, omitted or suffered to be done by the Trustee or the Company in
reliance thereon, whether or not notation of such action is made upon such
Security.

       (f) The Company may set any day as a record date for the purpose of
determining the Holders of Outstanding Securities of any series entitled to
give, make or take any request, demand, authorization, direction, notice,
consent,

                                      13
<PAGE>
 
waiver or other action provided or permitted by this Indenture to be given, made
or taken by Holders of Securities of such series, provided that the Company may
not set a record date for, and the provisions of this paragraph shall not apply
with respect to, the giving or making of any notice, declaration, request or
direction referred to in the next paragraph.  If any record date is set pursuant
to this paragraph, the Holders of Outstanding Securities of the relevant series
on such record date, and no other Holders, shall be entitled to take the
relevant action, whether or not such Holders remain Holders after such record
date, provided that no such action shall be effective hereunder unless taken on
or prior to the applicable Expiration Date by Holders of the requisite principal
amount of Outstanding Securities of such series on such record date.  Nothing in
this paragraph shall be construed to prevent the Company from setting a new
record date for any action for which a record date has previously been set
pursuant to this paragraph (whereupon the record date previously set shall
automatically and with no action by any Person be cancelled and of no effect),
and nothing in this paragraph shall be construed to render ineffective any
action taken by Holders of the requisite principal amount of Outstanding
Securities of the relevant series on the date such action is taken.  Promptly
after any record date is set pursuant to this paragraph, the Company, at its own
expense, shall cause notice of such record date, the proposed action by Holders
and the applicable Expiration Date to be given to the Trustee in writing and to
each Holder of Securities of the relevant series in the manner set forth in
Section 1.6.

       The Trustee may set any day as a record date for the purpose of
determining the Holders of Outstanding Securities of any series entitled to join
in the giving or making of (i) any Notice of Default, (ii) any declaration of
acceleration referred to in Section 5.2, (iii) any request to institute
proceedings referred to in Section 5.7(2) or (iv) any direction referred to in
Section 5.12, in each case with respect to Securities of such series.  If any
record date is set pursuant to this paragraph, the Holders of Outstanding
Securities of such series on such record date, and no other Holders, shall be
entitled to join in such notice, declaration, request or direction, whether or
not such Holders remain Holders after such record date, provided that no such
action shall be effective hereunder unless taken on or prior to the applicable
Expiration Date by Holders of the requisite principal amount of Outstanding
Securities of such series on such record date.  Nothing in this paragraph shall
be construed to prevent the Trustee from setting a new record date for any
action for which a record date has previously been set pursuant to this
paragraph (whereupon the record date previously set shall automatically and with
no action by any Person be cancelled and of no effect), and nothing in this
paragraph shall be construed to render ineffective any action

                                      14
<PAGE>
 
taken by Holders of the requisite principal amount of Outstanding Securities of
the relevant series on the date such action is taken.  Promptly after any record
date is set pursuant to this paragraph, the Trustee, at the Company's expense,
shall cause notice of such record date, the proposed action by Holders and the
applicable Expiration Date to be given to the Company in writing and to each
Holder of Securities of the relevant series in the manner set forth in 
Section 1.6.

       With respect to any record date set pursuant to this Section, the party
hereto which sets such record date may designate any day as the "Expiration
Date" and from time to time may change the Expiration Date to any earlier or
later day, provided that no such change shall be effective unless notice of the
proposed new Expiration Date is given to the other party hereto in writing, and
to each Holder of Securities of the relevant series in the manner set forth in
Section 10.6, on or prior to the existing Expiration Date.  If an Expiration
Date is not designated with respect to any record date set pursuant to this
Section, the party hereto which set such record date shall be deemed to have
initially designated the 180th day after such record date as the Expiration Date
with respect thereto, subject to its right to change the Expiration Date as
provided in this paragraph.  Notwithstanding the foregoing, no Expiration Date
shall be later than the 180th day after the applicable record date.

       (g) Without limiting the foregoing, a Holder entitled hereunder to take
any action hereunder with regard to any particular Security may do so with
regard to all or any part of the principal amount of such Security or by one or
more duly appointed agents each of which may do so pursuant to such appointment
with regard to all or any part of such principal amount.

       SECTION 1.5.   Notices, Etc. to Trustee and Company.

       Any request, demand, authorization, direction, notice, consent, waiver or
Act of Holders or other document provided or permitted by this Indenture to be
made upon, given or furnished to, or filed with,

       (1) the Trustee by any Holder, any holder of Preference Securities or the
Company shall be sufficient for every purpose hereunder if made, given,
furnished or filed in writing to or with the Trustee at its Corporate Trust
Office, or

       (2) the Company by the Trustee, any Holder or any holder of Preference
Securities shall be sufficient for every purpose (except as otherwise provided
in Section 5.1) hereunder if in writing and mailed, first class, postage


                                      15
<PAGE>
 
prepaid, to the Company addressed to it at the address of its principal office
specified in the first paragraph of this Indenture or at any other address
previously furnished in writing to the Trustee by the Company.

       SECTION 1.6.   Notice to Holders; Waiver.

       Where this Indenture provides for notice to Holders of any event, such
notice shall be sufficiently given (unless otherwise herein expressly provided)
if in writing and mailed, first class postage prepaid, to each Holder affected
by such event, at the address of such Holder as it appears in the Securities
Register, not later than the latest date, and not earlier than the earliest
date, prescribed for the giving of such notice.  In any case where notice to
Holders is given by mail, neither the failure to mail such notice, nor any
defect in any notice so mailed, to any particular Holder shall affect the
sufficiency of such notice with respect to other Holders.  Where this Indenture
provides for notice in any manner, such notice may be waived in writing by the
Person entitled to receive such notice, either before or after the event, and
such waiver shall be the equivalent of such notice.  Waivers of notice by
Holders shall be filed with the Trustee, but such filing shall not be a
condition precedent to the validity of any action taken in reliance upon such
waiver.

       SECTION 1.7.   Conflict with Trust Indenture Act.

       If any provision of this Indenture limits, qualifies or conflicts with
the duties imposed by any of Sections 310 to 317, inclusive, of the Trust
Indenture Act through operation of Section 318(c) thereof, such imposed duties
shall control.

       SECTION 1.8.   Effect of Headings and Table of Contents.

       The Article and Section headings herein and the Table of Contents are for
convenience only and shall not affect the construction hereof.

       SECTION 1.9.   Successors and Assigns.

       All covenants and agreements in this Indenture by the Company shall bind
its successors and assigns, whether so expressed or not.

       SECTION 1.10.  Separability Clause.

       In case any provision in this Indenture or in the Securities shall be
invalid, illegal or unenforceable, the validity, legality and enforceability of
the remaining provisions shall not in any way be affected or impaired thereby.

                                      16
<PAGE>
 
       SECTION 1.11.  Benefits of Indenture.

       Nothing in this Indenture or in the Securities, express or implied, shall
give to any Person, other than the parties hereto and their successors and
assigns, the holders of Senior Debt, the Holders of the Securities and, to the
extent provided in Sections 5.2, 5.8, 5.9, 5.11, 5.13, 9.1, 9.2, 10.6, 13.5,
13.6 and 13.7, the holders of Preference Securities, any benefit or any legal or
equitable right, remedy or claim under this Indenture.

       SECTION 1.12.  Governing Law.

  THIS INDENTURE AND THE SECURITIES SHALL BE GOVERNED BY AND CONSTRUED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK WITHOUT REGARD TO CONFLICTS OF
LAWS PRINCIPLES THEREOF.

       SECTION 1.13.  Non-Business Days.

       In any case where any Interest Payment Date, Redemption Date or Stated
Maturity of any Security shall not be a Business Day, then (notwithstanding any
other provision of this Indenture or the Securities) payment of interest or
principal (and premium, if any) need not be made on such date, but may be made
on the next succeeding Business Day (and no interest shall accrue for the period
from and after such Interest Payment Date, Redemption Date or Stated Maturity,
as the case may be, until such next succeeding Business Day) except that, if
such Business Day is in the next succeeding calendar year, such payment shall be
made on the immediately preceding Business Day (in each case with the same force
and effect as if made on the Interest Payment Date or Redemption Date or at the
Stated Maturity).


                                   ARTICLE II

                                 SECURITY FORMS

       SECTION 2.1.   Forms Generally.

       The Securities of each series and the Trustee's certificate of
authentication shall be in substantially the forms set forth in this Article, or
in such other form or forms as shall be established by or pursuant to a Board
Resolution or in one or more indentures supplemental hereto, in each case with
such appropriate insertions, omissions, substitutions and other variations as
are required or permitted by this Indenture and may have such letters, numbers
or other marks of identification and such legends or endorsements placed thereon
as may be required to comply with applicable tax laws or the rules of any
securities exchange or automated quotation system on which the Securities may be

                                      17
<PAGE>
 
listed or traded as may, consistently herewith, be determined by the officers
executing such Securities, as conclusively evidenced by their execution of the
Securities.  If the form of Securities of any series is established by action
taken pursuant to a Board Resolution, a copy of an appropriate record of such
action shall be certified by the Secretary or an Assistant Secretary of the
Company and delivered to the Trustee at or prior to the delivery of the Company
Order contemplated by Section 3.3 with respect to the authentication and
delivery of such Securities.

       The Trustee's certificates of authentication shall be substantially in
the form set forth in this Article.

       The definitive Securities shall be typewritten, printed, lithographed or
engraved or produced by any combination of these methods, if required by any
securities exchange or automated quotation system on which the Securities may be
listed or traded, on a steel engraved border or steel engraved borders or may be
produced in any other manner permitted by the rules of any securities exchange
or automated quotation system on which the Securities may be listed or traded,
all as determined by the officers executing such Securities, as evidenced by
their execution of such Securities.

       SECTION 2.2.   Form of Face of Security.

                        HOUSTON LIGHTING & POWER COMPANY
                              (Title of Security)

No.              $                                       CUSIP No.____________

       HOUSTON LIGHTING & POWER COMPANY, a corporation organized and existing
under the laws of Texas (hereinafter called the "Company", which term includes
any successor corporation under the Indenture hereinafter referred to), for
value received, hereby promises to pay to ______________, or registered assigns,
the principal sum of __________ Dollars on _____________, __; provided that the
Company may, subject to certain conditions specified in Section 3.14 of the
Indenture, (i) advance the Stated Maturity of the principal of this Security to
a date not earlier than _________, ________ and (ii) extend the Stated Maturity
of the principal of this Security at any time on one or more occasions, but in
no event to a date later than _______, ____.  The Company further promises to
pay interest on said principal sum from _________, ________ or from the most
recent interest payment date (each such date, an "Interest Payment Date") on
which interest has been paid or duly provided for, __________ (subject to
deferral as set forth herein) in arrears on [specify Interest Payment Dates] of
each year, commencing ____________________, _____, at the rate of _____% per
annum, until the principal

                                      18
<PAGE>
 
hereof shall have become due and payable, plus Additional Interest, to the
extent permitted by applicable law, if any, until the principal hereof is paid
or duly provided for or made available for payment and on any overdue principal
and (without duplication and to the extent that payment of such interest is
enforceable under applicable law) on any overdue installment of interest at the
rate of ____% per annum, compounding _____. The amount of interest payable for
any period shall be computed on the basis of twelve 30-day months and a 360-day
year. The amount of interest payable for any partial period shall be computed on
the basis of a 360-day year of twelve 30-day months and the days elapsed in any
partial month. In the event that any date on which interest is payable on this
Security is not a Business Day, then a payment of the interest payable on such
date will be made on the next succeeding day which is a Business Day (and
without any interest or other payment in respect of any such delay), except
that, if such Business Day is in the next succeeding calendar year, such payment
shall be made on the immediately preceding Business Day, in each case with the
same force and effect as if made on the date the payment was originally payable.
A "Business Day" shall mean any day other than (i) a Saturday or Sunday, (ii) a
day on which banking institutions in The City of New York are authorized or
required by law or executive order to remain closed or (iii) a day on which the
Corporate Trust Office of the Trustee, or, with respect to the Securities of
this series initially issued to an HL&P Trust, the principal corporate trust
office of the Property Trustee under the Trust Agreement hereinafter referred to
for HL&P Capital Trust [ ] is closed for business. The interest installment so
payable, and punctually paid or duly provided for, on any Interest Payment Date
will, as provided in the Indenture, be paid to the Person in whose name this
Security (or one or more Predecessor Securities) is registered at the close of
business on the Regular Record Date for such interest installment, which shall
be the [specify Regular Record Dates] next preceding the applicable Interest
Payment Date. Any such interest installment not so punctually paid or duly
provided for shall forthwith cease to be payable to the Holder on such Regular
Record Date and may either be paid to the Person in whose name this Security (or
one or more Predecessor Securities) is registered at the close of business on a
Special Record Date for the payment of such Defaulted Interest to be fixed by
the Trustee, notice whereof shall be given to Holders of Securities of this
series not less than 10 days prior to such Special Record Date, or be paid at
any time in any other lawful manner not inconsistent with the requirements of
any securities exchange or automated quotation system on which the Securities of
this series may be listed or traded, and upon such notice as may be required by
such exchange or automated quotation system, all as more fully provided in said
Indenture.

       [If applicable, insert--So long as no Event of Default has occurred and
is continuing, the Company shall have the right at any time during the term of
this Security to

                                      19
<PAGE>
 
defer payment of interest on this Security, at any time or from time to time,
for up to ____ consecutive ____ interest payment periods with respect to each
deferral period (each an "Extension Period"), during which Extension Periods
the Company shall have the right to make partial payments of interest on any
Interest Payment Date, and at the end of which the Company shall pay all
interest then accrued and unpaid (together with Additional Interest thereon to
the extent permitted by applicable law); provided, however, that no Extension
Period shall extend beyond the Stated Maturity of the principal of this
Security; provided, further, that during any such Extension Period, the Company
shall not, (i) declare or pay any dividends or distributions on, or redeem,
purchase, acquire or make a liquidation payment with respect to, any of the
Company's capital stock or (ii) make any payment of principal of or interest or
premium, if any, on or repay, repurchase or redeem any debt security of the
Company that, in either case, ranks pari passu with or junior in interest to
this Security or make any guarantee payments with respect to any guarantee by
the Company of the debt securities of any Subsidiary of the Company if such
guarantee ranks pari passu with or junior in interest to this Security (other
than (a) dividends or distributions in capital stock of the Company, (b) any
declaration of a dividend under a Rights Plan or in connection with the
implementation of a Rights Plan, the issuance of capital stock of the Company
under a Rights Plan or the redemption or repurchase of any rights distributed
pursuant to a Rights Plan,(c) payments under any HL&P Guarantee, and (d)
purchases of Common Stock related to the issuance of Common Stock or rights
under any of the Company's benefit plans for its directors, officers or
employees, related to the issuance of Common Stock or rights under a dividend
reinvestment and stock purchase plan, or related to the issuance of Common Stock
(or securities convertible into or exchangeable for Common Stock) as
consideration in an acquisition transaction that was entered into prior to the
commencement of such Extension Period). Prior to the termination of any such
Extension Period, the Company may further defer the payment of interest,
provided that no Extension Period shall exceed _____ consecutive ______ or
extend beyond the Stated Maturity of the principal of this Security. Upon the
termination of any such Extension Period and upon the payment of all accrued and
unpaid interest and any Additional Interest then due, the Company may elect to
begin a new Extension Period, subject to the above requirements. No interest
shall be due and payable during an Extension Period except at the end thereof.
The Company shall give the Holder of this Security and the Trustee notice of its

                                      20
<PAGE>
 
election to begin any Extension Period at least one Business Day prior to the
next succeeding Interest Payment Date on which interest on this Security would
be payable but for such deferral or, with respect to the Securities issued to an
HL&P Trust, so long as such Securities are held by such HL&P Trust, prior to the
earlier of (i) the next succeeding date on which Distributions on the Preference
Securities would be payable but for such deferral or (ii) the date the
Administrative Trustees are required to give notice to any securities exchange
or other applicable self-regulatory organization or to holders of such
Preference Securities of the record date or the date such Distributions are
payable, but in any event not less than one Business Day prior to such record
date.

       Payment of the principal of (and premium, if any) and interest on this
Security will be made at the office or agency of the Company maintained for that
purpose in the United States, in such coin or currency of the United States of
America as at the time of payment is legal tender for payment of public and
private debts; provided, however, that at the option of the Company payment of
interest may be made (i) by check mailed to the address of the Person entitled
thereto as such address shall appear in the Securities Register or (ii) by wire
transfer in immediately available funds at such place and to such account as may
be designated in writing by the Person entitled thereto as specified in the 
Securities Register.

       The indebtedness evidenced by this Security is, to the extent provided in
the Indenture, subordinate and subject in right of payment to the prior payment
in full of all Senior Debt, and this Security is issued subject to the
provisions of the Indenture with respect thereto.  Each Holder of this Security,
by accepting the same, (a) agrees to and shall be bound by such provisions, (b)
authorizes and directs the Trustee on his behalf to take such actions as may be
necessary or appropriate to effectuate the subordination so provided and (c)
appoints the Trustee his attorney-in-fact for any and all such purposes.  Each
Holder hereof, by his acceptance hereof, waives all notice of the acceptance of
the subordination provisions contained herein and in the Indenture by each
holder of Senior Debt, whether now outstanding or hereafter incurred, and waives
reliance by each such holder upon said provisions.

       Reference is hereby made to the further provisions of this Security set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

       Unless the certificate of authentication hereon has been executed by the
Trustee referred to on the reverse hereof by manual signature, this Security
shall not be entitled to

                                      21
<PAGE>
 
any benefit under the Indenture or be valid or obligatory for any purpose.

       IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed under its corporate seal.


                                HOUSTON LIGHTING & POWER COMPANY



                                By:
                                    ----------------------------
                                    [Authorized Officer]
 

Attest:

---------------------------
Secretary

       SECTION 2.3.   Form of Reverse of Security.

       This Security is one of a duly authorized issue of securities of the
Company (herein called the "Securities"), issued and to be issued under a Junior
Subordinated Indenture, dated as of _________, 199__ (herein called the
"Indenture"), between the Company and The Bank of New York, as Trustee (herein
called the "Trustee", which term includes any successor trustee under the
Indenture), to which Indenture and all indentures supplemental thereto reference
is hereby made for a statement of the respective rights, limitations of rights,
duties and immunities thereunder of the Trustee, the Company and the Holders of
the Securities, and of the terms upon which the Securities are, and are to be,
authenticated and delivered.  This Security is one of the series designated on
the face hereof, limited in aggregate principal amount to $________________.

       All terms used in this Security that are defined in the Indenture or in
the Amended and Restated Trust Agreement, dated as of _____________________,
______, as amended (the "Trust Agreement"), for HL&P Capital Trust [  ], among
Houston Lighting & Power Company, as Depositor, and the Trustees named therein,
shall have the meanings assigned to them in the Indenture or the Trust
Agreement, as the case may be.

       The redemption provisions for each series of Securities shall be
established by or pursuant to a Board Resolution or in one or more indentures
supplemental hereto, in each case in accordance with the provisions of this
Indenture.

                                      22
<PAGE>
 
       In the event of redemption of this Security in part only, a new Security
or Securities of this series for the unredeemed portion hereof will be issued in
the name of the Holder hereof upon the cancellation hereof.

       The Indenture contains provisions for satisfaction and discharge of the
entire indebtedness of this Security upon compliance by the Company with certain
conditions set forth in the Indenture.

       The Indenture permits, with certain exceptions as therein provided, the
Company and the Trustee at any time to enter into a supplemental indenture or
indentures for the purpose of modifying in any manner the rights and obligations
of the Company and of the Holders of the Securities, with the consent of the
Holders of not less than a majority in principal amount of the Outstanding
Securities of all series to be affected by such supplemental indenture and, 
under certain circumstances, in the case of Securities of a Series issued to an 
HL&P Trust, the consent of holders of at least a majority in Aggregate
Liquidation Amount of Preference Securities then Outstanding. The Indenture also
contains provisions permitting Holders of specified percentages in principal
amount of the Securities of all series at the time Outstanding, on behalf of the
Holders of all Securities of such series, and in the case of Securities of a
Series issued to an HL&P Trust, the Holders of Preference Securities issued by
such HL&P Trust to waive compliance by the Company with certain provisions of
the Indenture and certain past defaults under the Indenture and their
consequences. Any such consent or waiver by the Holder of this Security shall be
conclusive and binding upon such Holder and upon all future Holders of this
Security and of any Security issued upon the registration of transfer hereof or
in exchange herefor or in lieu hereof, whether or not notation of such consent
or waiver is made upon this Security.

       [If the Security is not a Discount Security,--As provided in and subject
to the provisions of the Indenture, if an Event of Default with respect to the
Securities of this series at the time Outstanding occurs and is continuing, then
and in every such case the Trustee or the Holders of not less than 25% in
principal amount of the Outstanding Securities of this series may declare the
principal amount (and premium, if any) of all the Securities of this series to
be due and payable immediately, by a notice in writing to the Company (and to
the Trustee if given by Holders), provided that, in the case of the Securities
of this series issued to an HL&P Trust, if upon an Event of Default, the Trustee
or the Holders of not less than 25% in principal amount of the Outstanding
Securities of this series fails to declare the principal (and premium, if any)
of all the Securities of this series to be immediately due and payable, the
holders of at least 25% in aggregate Liquidation Amount of the Preference
Securities then outstanding shall have such right by a notice in writing to the
Company and the Trustee; and upon any such declaration the principal amount (and
premium, if any) of and the accrued interest (including any Additional Interest)
on all the Securities of this series shall become immediately due and payable,
provided that the payment of principal (and premium, if any) and interest
(including any

                                      23
<PAGE>
 
Additional Interest) on such Securities shall remain subordinated to the extent
provided in Article XIII of the Indenture.]
 
       [If the Security is a Discount Security,--As provided in and subject to
the provisions of the Indenture, if an Event of Default with respect to the
Securities of this series at the time Outstanding occurs and is continuing, then
and in every such case the Trustee or the Holders of not less than such portion
of the principal amount as may be specified in the terms of this series may
declare an amount of principal of (and premium, if any) the Securities of this
series to be due and payable immediately, by a notice in writing to the Company
(and to the Trustee if given by Holders), provided that, in the case of the
Securities of this series issued to an HL&P Trust, if upon an Event of Default,
the Trustee or the Holders of not less than 25% in principal amount of the
Outstanding Securities of this series fails to declare the principal of all the
Securities of this series to be immediately due and payable, the holders of at
least 25% in aggregate Liquidation Amount of the Preference Securities then
outstanding shall have such right by a notice in writing to the Company and the
Trustee. Upon any such declaration, such amount of the principal of (and
premium, if any) and the accrued interest (including any Additional Interest) on
all the Securities of this series shall become immediately due and payable,
provided that the payment of principal (and premium, if any) and interest
(including any Additional Interest) on such Securities shall remain subordinated
to the extent provided in Article XIII of the Indenture. Upon payment (i) of the
amount of principal so declared due and payable and (ii) of interest on any
overdue principal (and premium, if any) and overdue interest (in each case to
the extent that the payment of such interest shall be legally enforceable), all
of the Company's obligations in respect of the payment of the principal of and
interest, if any, on this Security shall terminate.]

       No reference herein to the Indenture and no provision of this Security or
of the Indenture shall alter or impair the obligation of the Company, which is
absolute and unconditional, to pay the principal of (and premium, if any) and
interest on this Security at the times, place and rate, and in the coin or
currency, herein prescribed.

       As provided in the Indenture and subject to certain limitations therein
set forth, the transfer of this Security is registrable in the Securities
Register, upon surrender of this Security for registration of transfer at the
office or agency of the Company maintained under Section 10.2 of the Indenture
duly endorsed by, or accompanied by a written instrument of transfer in form
satisfactory to the Company and the Securities Registrar duly executed by, the
Holder hereof or his attorney duly authorized in writing, and thereupon one or
more new Securities of this series, of authorized

                                      24
<PAGE>
 
denominations and for the same aggregate principal amount, will be issued to the
designated transferee or transferees.  No service charge shall be made for any
such registration of transfer or exchange, but the Company may require payment
of a sum sufficient to cover any tax or other governmental charge payable in
connection therewith.

       Prior to due presentment of this Security for registration of transfer,
the Company, the Trustee and any agent of the Company or the Trustee may treat
the Person in whose name this Security is registered as the owner hereof for all
purposes, whether or not this Security be overdue, and neither the Company, the
Trustee nor any such agent shall be affected by notice to the contrary.

       The Securities of this series are issuable only in registered form
without coupons in denominations of $___ and any integral multiple thereof.  As
provided in the Indenture and subject to certain limitations therein set forth,
the Securities of this series are exchangeable for a like aggregate principal
amount of Securities of such series of a different authorized denomination, as
requested by the Holder surrendering the same.

       The Company and, by its acceptance of this Security or a beneficial
interest therein, the Holder of, and any Person that acquires a beneficial
interest in, this Security agree that for United States Federal, state and local
tax purposes it is intended that this Security constitute indebtedness.

       THE INDENTURE AND THIS SECURITY SHALL BE GOVERNED BY AND CONSTRUED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK WITHOUT REGARD TO CONFLICTS OF
LAWS PRINCIPLES THEREOF.

  SECTION 2.4.   Additional Provisions Required in Global Security.

       Any Global Security issued hereunder shall, in addition to the provisions
contained in Sections 2.2 and 2.3, bear a legend in substantially the following
form:

       "This Security is a Global Security within the meaning of the Indenture
hereinafter referred to and is registered in the name of a Depositary or a
nominee of a Depositary.  This Security is exchangeable for Securities
registered in the name of a person other than the Depositary or its nominee only
in the limited circumstances described in the Indenture and may not be
transferred except as a whole by the Depositary to a nominee of the Depositary
or by a nominee of the Depositary to the Depositary or another nominee of the
Depositary."

                                      25
<PAGE>
 
  SECTION 2.5.   Form of Trustee's Certificate of Authentication.

       This is one of the Securities referred to in the within mentioned
Indenture.

Dated:
                           The Bank of New York,
                                as Trustee

                                By:
                                   ----------------------------
                                      Authorized Signatory


                                  ARTICLE III

                                 THE SECURITIES

       SECTION 3.1.   Title and Terms.

       The aggregate principal amount of Securities which may be authenticated
and delivered under this Indenture is unlimited.

       The Securities may be issued in one or more series.  There shall be
established in or pursuant to a Board Resolution, and set forth in an Officers'
Certificate, or established in one or more indentures supplemental hereto, prior
to the issuance of Securities of a series:

       (a) the title of the Securities of such series, which shall distinguish
the Securities of the series from all other Securities;

       (b) the limit, if any, upon the aggregate principal amount of the
Securities of such series which may be authenticated and delivered under this
Indenture (except for Securities authenticated and delivered upon registration
of transfer of, or in exchange for, or in lieu of, other Securities of the
series pursuant to Section 3.4, 3.5, 3.6, 9.6 or 11.6 and except for any
Securities which, pursuant to Section 3.3, are deemed never to have been
authenticated and delivered hereunder); provided, however, that the authorized
aggregate principal amount of such series may be increased above such amount by
a Board Resolution to such effect;

       (c) the Stated Maturity or Maturities on which the principal of the
Securities of such series is payable or the method of determination thereof and
the right, pursuant to Section 3.14 or as otherwise set forth therein, of the
Company to advance or extend the Stated Maturity of a series of Securities;

                                      26
<PAGE>
 
       (d) the rate or rates, if any, at which the Securities of such series
shall bear interest, if any, the rate or rates and extent to which Additional
Interest, if any, shall be payable in respect of any Securities of such series,
the Interest Payment Dates on which such interest shall be payable, the right,
pursuant to Section 3.11 or as otherwise set forth therein, of the Company to
defer or extend an Interest Payment Date, and the Regular Record Date for the
interest payable on any Interest Payment Date or the method by which any of the
foregoing shall be determined;

       (e) the place or places where the principal of (and premium, if any) and
interest on the Securities of such series shall be payable, the place or places
where the Securities of such series may be presented for registration of
transfer or exchange, and the place or places where notices and demands to or
upon the Company in respect of the Securities of such series may be made;

       (f) the period or periods within or the date or dates on which, if any,
the price or prices at which and the terms and conditions upon which the
Securities of such series may be redeemed, in whole or in part, at the option of
the Company;

       (g) the obligation or the right, if any, of the Company to redeem, repay
or purchase the Securities of such series pursuant to any sinking fund,
amortization or analogous provisions, or at the option of a Holder thereof, and
the period or periods within which, the price or prices at which, the currency
or currencies (including currency unit or units) in which and the other terms
and conditions upon which Securities of the series shall be redeemed, repaid or
purchased, in whole or in part, pursuant to such obligation;

       (h) the denominations in which any Securities of such series shall be
issuable, if other than denominations of $25 and any integral multiple thereof;

       (i) if other than Dollars, the currency or currencies (including currency
unit or units) in which the principal of (and premium, if any) and interest, if
any, on the Securities of the series shall be payable, or in which the
Securities of the series shall be denominated;

       (j) the additions, modifications or deletions, if any, in the Events of
Default or covenants of the Company set forth herein with respect to the
Securities of such series;

       (k) if other than the principal amount thereof, the portion of the
principal amount of Securities of such series that shall be payable upon
declaration of acceleration of the Maturity thereof;

                                      27
<PAGE>
 
       (l) the additions or changes, if any, to this Indenture with respect to
the Securities of such series as shall be necessary to permit or facilitate the
issuance of the Securities of such series in bearer form, registrable or not
registrable as to principal, and with or without interest coupons;

       (m) any index or indices used to determine the amount of payments of
principal of and premium, if any, on the Securities of such series or the manner
in which such amounts will be determined;

       (n) whether the Securities of the series, or any portion thereof, shall
initially be issuable in the form of a temporary Global Security representing
all or such portion of the Securities of such series and provisions for the
exchange of such temporary Global Security for definitive Securities of such
series;

       (o) if applicable, that any Securities of the series shall be issuable in
whole or in part in the form of one or more Global Securities and, in such case,
the respective Depositaries for such Global Securities, the form of any legend
or legends which shall be borne by any such Global Security in addition to or in
lieu of that set forth in Section 2.4 and any circumstances in addition to or in
lieu of those set forth in Section 3.5 in which any such Global Security may be
exchanged in whole or in part for Securities registered, and any transfer of
such Global Security in whole or in part may be registered, in the name or names
of Persons other than the Depositary for such Global Security or a nominee
thereof;

       (p) the appointment of any Paying Agent or Agents for the Securities of
such series;

       (q) the terms of any right to convert or exchange Securities of such
series into any other securities or property of the Company, and the additions
or changes, if any, to this Indenture with respect to the Securities of such
series to permit or facilitate such conversion or exchange;

       (r) the relative degree, if any, to which the Securities of the series
shall be senior to or be subordinated to other series of Securities in right of
payment, whether such other series of Securities are Outstanding or not; and

                                      28
<PAGE>
 
       (s) any other terms of the Securities of such series (which terms shall
not be inconsistent with the provisions of this Indenture).

       All Securities of any one series shall be substantially identical except
as to denomination and except as may otherwise be provided herein or in or
pursuant to such Board Resolution and set forth in such Officers' Certificate or
in any such indenture supplemental hereto.

       If any of the terms of the Securities of any series are established by
action taken pursuant to a Board Resolution, a copy of an appropriate record of
such action shall be certified by the Secretary or an Assistant Secretary of the
Company and delivered to the Trustee at or prior to the delivery of the
Officers' Certificate setting forth the terms of the series.

       The Securities shall be subordinated in right of payment to Senior Debt
as provided in Article XIII.

       SECTION 3.2.   Denominations.

       The Securities of each series shall be in registered form without coupons
and shall be issuable in denominations as contemplated by Section 3.1.

       SECTION 3.3.   Execution, Authentication, Delivery and Dating.

       The Securities shall be executed on behalf of the Company by its
President or one of its Vice Presidents under its corporate seal reproduced or
impressed thereon and attested by its Secretary or one of its Assistant
Secretaries.  The signature of any of these officers on the Securities may be
manual or facsimile.

       Securities bearing the manual or facsimile signatures of individuals who
were at any time the proper officers of the Company shall bind the Company,
notwithstanding that such individuals or any of them have ceased to hold such
offices prior to the authentication and delivery of such Securities or did not
hold such offices at the date of such Securities.  At any time and from time to
time after the execution and delivery of this Indenture, the Company may deliver
Securities of any series executed by the Company to the Trustee for
authentication, together with a Company Order for the authentication and
delivery of such Securities, and the Trustee in accordance with the Company
Order shall authenticate and make available for delivery such Securities. If the
form or terms of the Securities of the series have been established by or
pursuant to one or more Board Resolutions as permitted by Sections 2.1 and 3.1,
in authenticating such
                                      29
<PAGE>
 
Securities, and accepting the additional responsibilities under this Indenture
in relation to such Securities, the Trustee shall be entitled to receive, and
(subject to Section 6.1) shall be fully protected in conclusively relying upon,
an Opinion of Counsel stating,

       (1) if the form of such Securities has been established by or pursuant to
Board Resolution as permitted by Section 2.1, that such form has been
established in conformity with the provisions of this Indenture;

       (2) if the terms of such Securities have been established by or pursuant
to Board Resolution as permitted by Section 3.1, that such terms have been
established in conformity with the provisions of this Indenture; and

       (3) that such Securities, when authenticated and delivered by the Trustee
and issued by the Company in the manner and subject to any conditions specified
in such Opinion of Counsel, will constitute valid and legally binding
obligations of the Company enforceable in accordance with their terms, subject
to bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and
similar laws of general applicability relating to or affecting creditors' rights
and to general equity principles.

If such form or terms have been so established, the Trustee shall not be
required to authenticate such Securities if the issue of such Securities
pursuant to this Indenture will affect the Trustee's own rights, duties or
immunities under the Securities and this Indenture or otherwise in a manner
which is not reasonably acceptable to the Trustee.

  Notwithstanding the provisions of Section 3.1 and of the preceding paragraph,
if all Securities of a series are not to be originally issued at one time, it
shall not be necessary to deliver the Officers' Certificate otherwise required
pursuant to Section 3.1 or the Company Order and Opinion of Counsel otherwise
required pursuant to such preceding paragraph at or prior to the authentication
of each Security of such series if such documents are delivered at or prior to
the authentication upon original issuance of the first Security of such series
to be issued.

  Each Security shall be dated the date of its authentication.

  No Security shall be entitled to any benefit under this Indenture or be valid
or obligatory for any purpose, unless there appears on such Security a
certificate of authentication substantially in the form provided for herein
executed by the Trustee by the manual signature of one of its authorized
signatories, and such certificate upon any Security shall be

                                      30
<PAGE>
 
conclusive evidence, and the only evidence, that such Security has been duly
authenticated and delivered hereunder.  Notwithstanding the foregoing, if any
Security shall have been authenticated and delivered hereunder but never issued
and sold by the Company, and the Company shall deliver such Security to the
Trustee for cancellation as provided in Section 3.9, for all purposes of this
Indenture such Security shall be deemed never to have been authenticated and
delivered hereunder and shall never be entitled to the benefits of this
Indenture.

       SECTION 3.4.   Temporary Securities.

       Pending the preparation of definitive Securities of any series, the
Company may execute, and upon Company Order the Trustee shall authenticate and
make available for delivery, temporary Securities which are printed,
lithographed, typewritten, mimeographed or otherwise produced, in any
denomination, substantially of the tenor of the definitive Securities of such
series in lieu of which they are issued and with such appropriate insertions,
omissions, substitutions and other variations as the officers executing such
Securities may determine, as evidenced by their execution of such Securities.

       If temporary Securities of any series are issued, the Company will cause
definitive Securities of such series to be prepared without unreasonable delay.
After the preparation of definitive Securities, the temporary Securities shall
be exchangeable for definitive Securities upon surrender of the temporary
Securities at the office or agency of the Company designated for that purpose
without charge to the Holder.  Upon surrender for cancellation of any one or
more temporary Securities, the Company shall execute and the Trustee shall
authenticate and make available for delivery in exchange therefor one or more
definitive Securities of the same series, of any authorized denominations having
the same Original Issue Date and Stated Maturity and having the same terms as
such temporary Securities. Until so exchanged, the temporary Securities of any
series shall in all respects be entitled to the same benefits under this
Indenture as definitive Securities of such series.

       SECTION 3.5.   Registration, Transfer and Exchange.

       The Company shall cause to be kept at the Corporate Trust Office of the
Trustee a register in which, subject to such reasonable regulations as it may
prescribe, the Company shall provide for the registration of Securities and of
transfers of Securities.  Such register is herein sometimes referred to as the
"Securities Register."  The Trustee is hereby appointed "Securities Registrar"
for the purpose of registering Securities and transfers of Securities as herein
provided.  If any indenture supplemental hereto refers to any

                                      31
<PAGE>
 
transfer agents (in addition to the Securities Registrar) initially designated
by the Company with respect to any series of Securities, the Company may at any
time rescind the designation of any such transfer agent or approve a change in
the location through which any such transfer agent acts, provided that the
Company maintains a transfer agent in each place of payment for such series.
The Company may at any time designate additional transfer agents with respect to
any series of Securities.

       Upon surrender for registration of transfer of any Security at the office
or agency of the Company designated for that purpose the Company shall execute,
and the Trustee shall authenticate and deliver, in the name of the designated
transferee or transferees, one or more new Securities of the same series of any
authorized denominations, of a like aggregate principal amount, of the same
Original Issue Date and Stated Maturity and having the same terms.

       At the option of the Holder, Securities may be exchanged for other
Securities of the same series of any authorized denominations, of a like
aggregate principal amount, of the same Original Issue Date and Stated Maturity
and having the same terms, upon surrender of the Securities to be exchanged at
such office or agency.  Whenever any Securities are so surrendered for exchange,
the Company shall execute, and the Trustee shall authenticate and deliver, the
Securities which the Holder making the exchange is entitled to receive.

       All Securities issued upon any transfer or exchange of Securities shall
be the valid obligations of the Company, evidencing the same debt, and entitled
to the same benefits under this Indenture, as the Securities surrendered upon
such transfer or exchange.

       Every Security presented or surrendered for transfer or exchange shall be
duly endorsed, or be accompanied by a written instrument of transfer in form
satisfactory to the Company and the Securities Registrar, duly executed by the
Holder thereof or his attorney duly authorized in writing.

       No service charge shall be made to a Holder for any transfer or exchange
of Securities, but the Company may require payment of a sum sufficient to cover
any tax or other governmental charge that may be imposed in connection with any
transfer or exchange of Securities.

       The provisions of Clauses (1), (2), (3) and (4) below shall apply only to
Global Securities:

       (1) Each Global Security authenticated under this Indenture shall be
registered in the name of the Depositary

                                      32
<PAGE>
 
designated for such Global Security or a nominee thereof and delivered to such
Depositary or a nominee thereof or custodian therefor, and each such Global
Security shall constitute a single Security for all purposes of this Indenture.

       (2) Notwithstanding any other provision in this Indenture, no Global
Security may be exchanged in whole or in part for Securities registered, and no
transfer of a Global Security in whole or in part may be registered, in the name
of any Person other than the Depositary for such Global Security or a nominee
thereof unless (A) such Depositary (i) has notified the Company that it is
unwilling or unable to continue as Depositary for such Global Security or (ii)
has ceased to be a clearing agency registered under the Exchange Act at a time
when the Depositary is required to be so registered to act as depositary, in
each case unless the Company has approved a successor Depositary within 90 days,
(B) there shall have occurred and be continuing an Event of Default with respect
to such Global Security, (C) the Company in its sole discretion determines that
such Global Security will be so exchangeable or transferable or (D) there shall
exist such circumstances, if any, in addition to or in lieu of the foregoing as
have been specified for this purpose as contemplated by Section 3.1.

       (3) Subject to Clause (2) above, any exchange of a Global Security for
other Securities may be made in whole or in part, and all Securities issued in
exchange for a Global Security or any portion thereof shall be registered in
such names as the Depositary for such Global Security shall direct.

       (4) Every Security authenticated and delivered upon registration of
transfer of, or in exchange for or in lieu of, a Global Security or any portion
thereof, whether pursuant to this Section, Section 3.4, 3.6, 9.6 or 11.6 or
otherwise, shall be authenticated and delivered in the form of, and shall be, a
Global Security, unless such Security is registered in the name of a Person
other than the Depositary for such Global Security or a nominee thereof.

       Neither the Company nor the Trustee shall be required, pursuant to the
provisions of this Section, (a) to issue, transfer or exchange any Security of
any series during a period beginning at the opening of business 15 days before
the day of mailing of notice of redemption pursuant to Article XI and
ending at the close of business on the day of mailing of such notice of
redemption or (b) to transfer or exchange any Security so selected for
redemption in whole or in part, except, in the case of any Security to be
redeemed in part, any portion thereof not to be redeemed.

                                      33
<PAGE>
 
       SECTION 3.6.  Mutilated, Destroyed, Lost and Stolen Securities.

       If any mutilated Security is surrendered to the Trustee together with
such security or indemnity as may be required by the Company or the Trustee to
save each of them harmless, the Company shall execute and the Trustee shall
authenticate and make available for delivery in exchange therefor a new Security
of the same issue and series of like tenor and principal amount, having the same
Original Issue Date and Stated Maturity, and bearing a number not
contemporaneously outstanding.

       If there shall be delivered to the Company and to the Trustee (i)
evidence to their satisfaction of the destruction, loss or theft of any
Security, and (ii) such security or indemnity as may be required by them to save
each of them harmless, then, in the absence of notice to the Company or the
Trustee that such Security has been acquired by a bona fide purchaser, the
Company shall execute and upon its request the Trustee shall authenticate and
deliver, in lieu of any such destroyed, lost or stolen Security, a new Security
of the same issue and series of like tenor and principal amount, having the same
Original Issue Date and Stated Maturity as such destroyed, lost or stolen
Security, and bearing a number not contemporaneously outstanding.

       In case any such mutilated, destroyed, lost or stolen Security has become
or is about to become due and payable, the Company in its discretion may,
instead of issuing a new Security, pay such Security.

       Upon the issuance of any new Security under this Section, the Company may
require the payment of a sum sufficient to cover any tax or other governmental
charge that may be imposed in relation thereto and any other expenses (including
fees and expenses of counsel to the Company and fees and expenses of the
Trustee, its agents and counsel) connected therewith.

       Every new Security issued pursuant to this Section in lieu of any
destroyed, lost or stolen Security shall constitute an original additional
contractual obligation of the Company, whether or not the destroyed, lost or
stolen Security shall be at any time enforceable by anyone, and shall be
entitled to all the benefits of this Indenture equally and proportionately with
any and all other Securities of that series duly issued hereunder.

       The provisions of this Section are exclusive and shall preclude (to the
extent lawful) all other rights and remedies with respect to the replacement or
payment of mutilated, destroyed, lost or stolen Securities.

                                      34
<PAGE>
 
       SECTION 3.7.  Payment of Interest; Interest Rights Preserved.

       Interest on any Security of any series which is payable, and is
punctually paid or duly provided for, on any Interest Payment Date, shall be
paid to the Person in whose name that Security (or one or more Predecessor
Securities) is registered at the close of business on the Regular Record Date
for such interest in respect of Securities of such series, except that, unless
otherwise provided in the Securities of such series, interest payable on the
Stated Maturity of the principal of a Security shall be paid to the Person to
whom principal is paid.  The initial payment of interest on any Security of any
series which is issued between a Regular Record Date and the related Interest
Payment Date shall be payable as provided in such Security or in the Board
Resolution pursuant to Section 3.1 with respect to the related series of
Securities.  Except in the case of a Global Security, at the option of the
Company, interest on any series of Securities may be paid (i) by check mailed to
the address of the Person entitled thereto as it shall appear on the Securities
Register of such series or (ii) by wire transfer in immediately available funds
at such place and to such account as designated in writing by the Person
entitled thereto as specified in the Securities Register of such series.

       Any paying agents will be identified in a supplemental indenture hereto.
The Company may at any time designate additional paying agents or rescind the
designation of any paying agent; however, the Company at all times will be
required to maintain a paying agent in each place of payment for each series of
Securities.

       Except as described in Section 3.11, any interest on any Security which
is payable, but is not timely paid or duly provided for, on any Interest Payment
Date for Securities of such series (herein called "Defaulted Interest"), shall
forthwith cease to be payable to the registered Holder on the relevant Regular
Record Date by virtue of having been such Holder, and such Defaulted Interest
may be paid by the Company, at its election in each case, as provided in Clause
(1) or (2) below:

       (1)  The Company may elect to make payment of any Defaulted Interest to
the Persons in whose names the Securities of such series in respect of which
interest is in default (or their respective Predecessor Securities) are
registered at the close of business on a Special Record Date for the payment of
such Defaulted Interest, which shall be fixed in the following manner.  The
Company shall notify the Trustee in writing of the amount of Defaulted Interest
proposed to be paid on each Security and the date of the proposed payment, and
at the same time the Company shall

                                      35
<PAGE>
 
deposit with the Trustee an amount of money equal to the aggregate amount
proposed to be paid in respect of such Defaulted Interest or shall make
arrangements satisfactory to the Trustee for such deposit prior to the date of
the proposed payment, such money when deposited to be held in trust for the
benefit of the Persons entitled to such Defaulted Interest as in this Clause
provided.  Thereupon the Trustee shall fix a Special Record Date for the payment
of such Defaulted Interest which shall be not more than 15 days and not less
than 10 days prior to the date of the proposed payment and not less than 10 days
after the receipt by the Trustee of the notice of the proposed payment.  The
Trustee shall promptly notify the Company of such Special Record Date and, in
the name and at the expense of the Company, shall cause notice of the proposed
payment of such Defaulted Interest and the Special Record Date therefor to be
mailed, first class, postage prepaid, to each Holder of a Security of such
series at the address of such Holder as it appears in the Securities Register
not less than 10 days prior to such Special Record Date. Unless all of the
Securities of a series are held by an HL&P Trust, The Trustee shall, in the name
and at the expense of the Company, cause a similar notice to be published at
least once in a newspaper, customarily published in the English language on each
Business Day and of general circulation in the Borough of Manhattan, The City of
New York, but such publication shall not be a condition precedent to the
establishment of such Special Record Date. Notice of the proposed payment of
such Defaulted Interest and the Special Record Date therefor having been mailed
as aforesaid, such Defaulted Interest shall be paid to the Persons in whose
names the Securities of such series (or their respective Predecessor Securities)
are registered on such Special Record Date and shall no longer be payable
pursuant to the following Clause (2).

       (2) The Company may make payment of any Defaulted Interest in any other
lawful manner not inconsistent with the requirements of any securities exchange
or automated quotation system on which the Securities of the series in respect
of which interest is in default may be listed or traded and, upon such notice as
may be required by such exchange (or by the Trustee if the Securities are not
listed), if, after notice given by the Company to the Trustee of the proposed
payment pursuant to this Clause, such payment shall be deemed practicable by the
Trustee.

       Any interest on any Security which is deferred or extended pursuant to
Section 3.11 shall not be Defaulted Interest for the purposes of this Section
3.7.

       Subject to the foregoing provisions of this Section, each Security
delivered under this Indenture upon transfer of or in exchange for or in lieu of
any other Security shall carry the rights to interest accrued and unpaid, and to
accrue, which were carried by such other Security.

                                      36
<PAGE>
 
       SECTION 3.8.  Persons Deemed Owners.

       The Company, the Trustee and any agent of the Company or the Trustee may
treat the Person in whose name any Security is registered on the applicable
record date as the owner of such Security for the purpose of receiving payment
of principal of and (subject to Section 3.7) any interest on such Security and
for all other purposes whatsoever, whether or not such Security be overdue, and
neither the Company, the Trustee nor any agent of the Company or the Trustee
shall be affected by notice to the contrary.

       SECTION 3.9.   Cancellation.

       All Securities surrendered for payment, redemption, transfer or exchange
shall, if surrendered to any Person other than the Trustee, be delivered to the
Trustee, and any such Securities and Securities surrendered directly to the
Trustee for any such purpose shall be promptly canceled by it.  The Company may
at any time deliver to the Trustee for cancellation any Securities previously
authenticated and delivered hereunder which the Company may have acquired in any
manner whatsoever, and all Securities so delivered shall be promptly canceled by
the Trustee.  No Securities shall be authenticated in lieu of or in exchange for
any Securities canceled as provided in this Section, except as expressly
permitted by this Indenture.  All canceled Securities shall be returned by the
Trustee to the Company. 

       SECTION 3.10.  Computation of Interest.

       Except as otherwise specified as contemplated by Section 3.1 for
Securities of any series, interest on the Securities of each series for any
period shall be computed on the basis of a 360-day year of twelve 30-day months
and interest on the Securities of each series for any partial period shall be
computed on the basis of a 360-day year of twelve 30-day months and the number
of days elapsed in any partial month.

       SECTION 3.11.  Deferrals of Interest Payment Dates.

       If specified as contemplated by Section 2.1 or Section 3.1 with respect
to the Securities of a particular series, so long as no Event of Default has
occurred and is continuing, the Company shall have the right, at any time during
the term of such series, from time to time to defer the payment of interest on
such Securities for such period or periods as may be specified as contemplated
by Section 3.1 (each, an "Extension Period") during which Extension Periods the
Company shall have the right to make partial payments of interest on any
Interest Payment Date.  No Extension Period shall end on a date other than an
Interest Payment Date.  At

                                      37
<PAGE>
 
the end of any such Extension Period the Company shall pay all interest then
accrued and unpaid on the Securities (together with Additional Interest thereon,
if any, at the rate specified for the Securities of such series to the extent
permitted by applicable law) to the Persons in whose names that Securities are
registered at the close of business on the Regular Record Date with respect to
the Interest Payment Date at the end of such Extension Period; provided,
however, that no Extension Period shall extend beyond the Stated Maturity of the
principal of the Securities of such series; provided further, that during any
such Extension Period, the Company shall not, (i) declare or pay any dividends
or distributions on, or redeem, purchase, acquire or make a liquidation payment
with respect to, any of the Company's capital stock, or (ii) make any payment of
principal of or interest or premium, if any, on or repay, repurchase or redeem
any debt security of the Company that, in either case, ranks pari passu with or
junior in interest to the Securities of such series or make any guarantee
payments with respect to any guarantee by the Company of the debt securities of
any Subsidiary of the Company if such guarantee ranks pari passu with or junior
in interest to the securities of such series (other than (a) dividends or
distributions in the capital stock of the Company, (b) any declaration of a
dividend under a Rights Plan or in connection with the implementation of a
Rights Plan, the issuance of capital stock of the Company under a Rights Plan or
the redemption or repurchase of any rights distributed pursuant to a Rights
Plan, (c) payments under any HL&P Guarantee, and (d) purchases of Common Stock
related to the issuance of Common Stock or rights under any of the Company's
benefit plans for its directors, officers or employees, related to the issuance
of Common Stock or rights under a dividend reinvestment and stock purchase plan,
or related to the issuance of Common Stock (or securities convertible into or
exchangeable for Common Stock) as consideration in an acquisition transaction
that was entered into prior to the commencement of such Extension Period). Prior
to the termination of any such Extension Period, the Company may further defer
the payment of interest, provided that no Extension Period shall exceed the
period or periods specified in such Securities or extend beyond the Stated
Maturity of the principal of such Securities. Upon termination of any Extension
Period and upon the payment of all accrued and unpaid interest and any
Additional Interest then due on any Interest Payment Date, the Company may elect
to begin a new Extension Period, subject to the above requirements. No interest
shall be due and payable during an Extension Period, except at the end thereof.
The Company shall give the Holders

                                      38
<PAGE>
 
of the Securities of such series and the Trustee notice of its election to begin
any such Extension Period at least one Business Day prior to the next succeeding
Interest Payment Date on which interest on Securities of such series would be
payable but for such deferral or, with respect to the Securities of a series
issued to an HL&P Trust, so long as such Securities are held by such HL&P Trust,
prior to the earlier of (i) the next succeeding date on which Distributions on
the Preference Securities of such HL&P Trust would be payable but for such
deferral or (ii) the date the Administrative Trustees of such HL&P Trust are
required to give notice to any securities exchange or other applicable self-
regulatory organization or to holders of such Preference Securities of the
record date or the date such Distributions are payable, but in any event not
less than one Business Day prior to such record date.

       The Trustee shall promptly give notice of the Company's election to begin
any such Extension Period to the Holders of the Outstanding Securities of such
series.

       SECTION 3.12.  Right of Set-Off.

       With respect to the Securities of a series issued to an HL&P Trust,
notwithstanding anything to the contrary in the Indenture, the Company shall
have the right to set-off any payment it is otherwise required to make
thereunder in respect of any such Security to the extent the Company has
theretofore made, or is concurrently on the date of such payment making, a
payment under the HL&P Guarantee relating to such Security or under Section 5.8.

       SECTION 3.13.  Agreed Tax Treatment.

       Each Security issued hereunder shall provide that the Company and, by its
acceptance of a Security or a beneficial interest therein, the Holder of, and
any Person that acquires a beneficial interest in, such Security agree that for
United States Federal, state and local tax purposes it is intended that such
Security constitute indebtedness.

       SECTION 3.14.  Advancing or Extending of Stated Maturity.

       If specified as contemplated by Section 2.1 or Section 3.1 with respect
to the Securities of a particular series, the Company shall have the right to
(i) advance the Stated Maturity of the principal of the Securities of such
series at any time to any date not earlier than the first date on which the
Company has the right to redeem the Securities of such series, and (ii) extend
the Stated Maturity of the principal of the Securities of such series at any
time at its election for one or more periods, but in no event to a date

                                      39
<PAGE>
 
later than the 49th anniversary of the first Interest Payment Date following the
Original Issue Date of the Securities of such series; provided that, if the
Company elects to exercise its right to extend the Stated Maturity of the
principal of the Securities of such series pursuant to clause (ii), above, at
the time such election is made and at the time of extension (A) the Company is
not in bankruptcy, otherwise insolvent or in liquidation, (B) the Company is not
in default in the payment of any interest or principal on such Securities, (C)
in the case of any series of Securities issued to an HL&P Trust, such HL&P Trust
is not in arrears on payments of Distributions on the Preference Securities
issued by such HL&P Trust and no deferred Distributions are accumulated and (D)
if any of such Securities are held by any Person other than an HL&P Trust such
Securities are rated not less than BBB- by S&P or Baa3 by Moody's or the
equivalent by any other nationally recognized statistical rating organization.
In the event the Company elects to advance or extend the Stated Maturity of the
Securities, it shall give notice to the Trustee, and the Trustee shall give
notice of such advancing or extension to the Holders, no less than 30 and no
more than 60 days prior to the effectiveness thereof.

       SECTION 3.15.  CUSIP Numbers.

       The Company in issuing the Securities may use "CUSIP" numbers (if then
generally in use), and, if so, the Trustee shall use "CUSIP" numbers in notices
of redemption as a convenience to Holders; provided that any such notice may
state that no representation is made as to the correctness of such numbers
either as printed on the Securities or as contained in any notice of a
redemption and that reliance may be placed only on the other identification
numbers printed on the Securities, and any such redemption shall not be affected
by any defect in or omission of such numbers.  The Company shall promptly notify
the Trustee in writing of any change in CUSIP numbers.


                                   ARTICLE IV

                           SATISFACTION AND DISCHARGE

       SECTION 4.1.   Satisfaction and Discharge of Indenture.

       This Indenture shall, upon Company Request, cease to be of further effect
(except as to any surviving rights of registration of transfer or exchange of
Securities herein expressly provided for and as otherwise provided in this
Section 4.1) and the Trustee, on demand of and at the expense of the Company,
shall execute proper instruments acknowledging satisfaction and discharge of
this Indenture, when

       (1)  either

                                      40
<PAGE>
 
       (A) all Securities theretofore authenticated and delivered (other than
(i) Securities which have been destroyed, lost or stolen and which have been
replaced or paid as provided in Section 3.6 and (ii) Securities for whose
payment money has theretofore been deposited in trust or segregated and held in
trust by the Company and thereafter repaid to the Company or discharged from
such trust, as provided in Section 10.3) have been delivered to the Trustee for
cancellation; or

       (B) all such Securities not theretofore delivered to the Trustee for
cancellation

                 (i)    have become due and payable, or

                 (ii)   will become due and payable at their Stated Maturity
          within one year of the date of deposit, or

                 (iii)  are to be called for redemption within one year under
          arrangements satisfactory to the Trustee for the giving of notice of
          redemption by the Trustee in the name, and at the expense, of the
          Company,

     and the Company, in the case of Clause (B) (i), (ii) or (iii) above, has
     deposited or caused to be deposited with the Trustee as trust funds in
     trust for such purpose an amount in the currency or currencies in which the
     Securities of such series are payable sufficient to pay and discharge the
     entire indebtedness on such Securities not theretofore delivered to the
     Trustee for cancellation, for principal (and premium, if any) and interest
     (including any Additional Interest) to the date of such deposit (in the
     case of Securities which have become due and payable) or to the Stated
     Maturity or Redemption Date, as the case may be;

       (2) the Company has paid or caused to be paid all other sums payable
hereunder by the Company; and

       (3) the Company has delivered to the Trustee an Officers' Certificate and
an Opinion of Counsel each stating that all conditions precedent herein provided
for relating to the satisfaction and discharge of this Indenture have been
complied with.

Notwithstanding the satisfaction and discharge of this Indenture, the
obligations of the Company to the Trustee under Section 6.7, the obligations of
the Trustee to any Authenticating Agent under Section 6.14 and, if money shall
have been deposited with the Trustee pursuant to subclause (B) of clause (1) of
this Section, the obligations of the Company

                                      41
<PAGE>
 
under Section 4.2 and the last paragraph of Section 10.3 shall survive.

       SECTION 4.2.   Application of Trust Money.

       Subject to the provisions of the last paragraph of Section 10.3, all
money deposited with the Trustee pursuant to Section 4.1 shall be held in trust
and applied by the Trustee, in accordance with the provisions of the Securities
and this Indenture, to the payment, either directly or through any Paying Agent
(including the Company acting as its own Paying Agent) as the Trustee may
determine, to the Persons entitled thereto, of the principal (and premium, if
any) and interest (including any Additional Interest) for the payment of which
such money or obligations have been deposited with or received by the Trustee.


                                   ARTICLE V

                                    REMEDIES

       SECTION 5.1.   Events of Default.

       "Event of Default", wherever used herein with respect to the Securities
of any series, means any one of the following events (whatever the reason for
such Event of Default and whether it shall be voluntary or involuntary or be
effected by operation of law or pursuant to any judgment, decree or order of any
court or any order, rule or regulation of any administrative or governmental
body):

       (1) default in the payment of any interest upon any Security of that
series, including any Additional Interest in respect thereof, when it becomes
due and payable, and continuance of such default for a period of 30 days
(subject to the deferral of any interest payment date in the case of an
Extension Period); or

       (2) default in the payment of the principal of (or premium, if any, on)
any Security of that series at its Maturity; or

       (3) default in the performance, or breach, in any material respect, of
any covenant or warranty of the Company in this Indenture with respect to that
series (other than a covenant or warranty a default in the performance of which
or the breach of which is elsewhere in this Section specifically dealt with),
and continuance of such default or breach for a period of 90 days after there
has been given, by registered or certified mail, to the Company by the Trustee
or to the Company and the Trustee by the Holders of at least 25% in principal
amount of the Outstanding Securities of that series

                                      42
<PAGE>
 
a written notice specifying such default or breach and requiring it to be
remedied; or

       (4) the entry of a decree or order by a court having jurisdiction in the
premises adjudging the Company a bankrupt or insolvent, or approving as properly
filed a petition seeking reorganization, arrangement, adjustment or composition
of or in respect of the Company under any applicable Federal or State
bankruptcy, insolvency, reorganization or other similar law, or appointing a
receiver, liquidator, assignee, trustee, sequestrator (or other similar
official) of the Company or of any substantial part of its property or ordering
the winding up or liquidation of its affairs, and the continuance of any such
decree or order unstayed and in effect for a period of 60 consecutive days; or

       (5) the institution by the Company of proceedings to be adjudicated a
bankrupt or insolvent, or the consent by it to the institution of bankruptcy or
insolvency proceedings against it, or the filing by it of a petition or answer
or consent seeking reorganization or relief under any applicable Federal or
State bankruptcy, insolvency, reorganization or other similar law, or the
consent by it to the filing of any such petition or to the appointment of a
receiver, liquidator, assignee, trustee, sequestrator (or other similar
official) of the Company or of any substantial part of its property, or the
making by it of an assignment for the benefit for creditors, or the admission by
it in writing of its inability to pay its debts generally as they become due and
its willingness to be adjudicated a bankrupt, or the taking of corporate action
by the Company in furtherance of any such action; or

       (6) any other Event of Default provided with respect to Securities of
that series.

       SECTION 5.2.   Acceleration of Maturity; Rescission and Annulment.

       If an Event of Default (other than an Event of Default specified in
Section 5.1(4) or 5.1(5)) with respect to Securities of any series at the time
Outstanding occurs and is continuing, then and in every such case the Trustee or
the Holders of not less than 25% in principal amount of the Outstanding
Securities of that series may declare the principal amount (or, if the
Securities of that series are Discount Securities, such portion of the principal
amount as may be specified in the terms of that series) of all the Securities of
that series to be due and payable immediately, by a notice in writing to the
Company (and to the Trustee if given by Holders), provided that, in the case of
the Securities of a series issued to an HL&P Trust, if, upon an Event of
Default, the Trustee or the Holders of not less than 25% in principal amount of
the

                                      43
<PAGE>
 
Outstanding Securities of that series fail to declare the principal amount (or,
if the Securities of that series are Discount Securities, such portion of the
principal amount as may be specified in the terms of that series) of all the
Securities of that series to be immediately due and payable, the holders of at
least 25% in aggregate liquidation amount of the corresponding series of
Preference Securities then outstanding shall have such right by a notice in
writing to the Company and the Trustee; and upon any such declaration such
principal amount (or specified portion thereof) of and the accrued interest
(including any Additional Interest to the extent permitted under applicable law)
on all, the Securities of such series shall become immediately due and payable.
Payment of principal and interest (including any Additional Interest to the
extent permitted under applicable law) on such Securities shall remain
subordinated to the extent provided in Article XIII notwithstanding that such
amount shall become immediately due and payable as herein provided.

       If an Event of Default specified in Section 5.1(4) or 5.1(5) with respect
to Securities of any series at the time Outstanding occurs, the principal amount
of all the Securities of that series (or, if the Securities of that series are
Discount Securities, such portion of the principal amount of such Securities as
may be specified by the terms of that series) shall automatically, and without
any declaration or other action on the part of the Trustee or any Holder, become
immediately due and payable.

       At any time after such a declaration of acceleration with respect to
Securities of any series has been made and before a judgment or decree for
payment of the money due has been obtained by the Trustee as hereinafter in this
Article provided, the Holders of a majority in principal amount of the
Outstanding Securities of that series, by written notice to the Company and the
Trustee, may rescind and annul such declaration and its consequences if:

       (1) the Company has paid or deposited with the Trustee a sum sufficient
to pay:

       (A) all overdue installments of interest (including any Additional
Interest) on all Securities of that series,

       (B) the principal of (and premium, if any, on) any Securities of that
series which have become due otherwise than by such declaration of acceleration
and interest thereon at the rate borne by the Securities, and

       (C) all sums paid or advanced by the Trustee hereunder and the reasonable
compensation, expenses, disbursements and advances of the Trustee, its agents
and counsel; and

                                      44
<PAGE>
 
       (2) all Events of Default with respect to Securities of that series,
other than the non-payment of the principal of Securities of that series which
has become due solely by such acceleration, have been cured or waived as
provided in Section 5.13.

       In the case of Securities of a series issued to an HL&P Trust, the
holders of a majority in aggregate Liquidation Amount (as defined in the Trust
Agreement under which such HL&P Trust is formed) of the related series of
Preference Securities issued by such HL&P Trust shall also have the right to
rescind and annul such declaration and its consequences by written notice to the
Company and the Trustee, subject to the satisfaction of the conditions set forth
in Clauses (1) and (2) above of this Section 5.2.

       No such rescission shall affect any subsequent default or impair any
right consequent thereon.

       SECTION 5.3.   Collection of Indebtedness and Suits for Enforcement by
Trustee.

       The Company covenants that if:

       (1) default is made in the payment of any installment of interest
(including any Additional Interest) on any Security when such interest becomes
due and payable and such default continues for a period of 30 days, or

       (2) default is made in the payment of the principal of (and premium, if
any, on) any Security at the Maturity thereof,

the Company will, upon demand of the Trustee, pay to the Trustee, for the
benefit of the holders of such Securities, the whole amount then due and payable
on such Securities for principal, including any sinking fund payment or
analogous obligations (and premium, if any) and interest (including any
Additional Interest); and, in addition thereto, all amounts owing the Trustee,
its agents and counsel under Section 6.7.

       If the Company fails to pay such amounts forthwith upon such demand, the
Trustee, in its own name and as trustee of an express trust, may institute a
judicial proceeding for the collection of the sums so due and unpaid, and may
prosecute such proceeding to judgment or final decree, and may enforce the same
against the Company or any other obligor upon the Securities and collect the
moneys adjudged or decreed to be payable in the manner provided by law out of
the property of the Company or any other obligor upon the Securities, wherever
situated.

                                      45
<PAGE>
 
       If an Event of Default with respect to Securities of any series occurs
and is continuing, the Trustee may in its discretion proceed to protect and
enforce its rights and the rights of the Holders of Securities of such series by
such appropriate judicial proceedings as the Trustee shall deem most effectual
to protect and enforce any such rights, whether for the specific enforcement of
any covenant or agreement in this Indenture or in aid of the exercise of any
power granted herein, or to enforce any other proper remedy.

       SECTION 5.4.   Trustee May File Proofs of Claim.

       In case of the pendency of any receivership, insolvency, liquidation,
bankruptcy, reorganization, arrangement, adjustment, composition or other
judicial proceeding relative to the Company or any other obligor upon the
Securities or the property of the Company or of such other obligor or their
creditors,

       (a) the Trustee (irrespective of whether the principal of the Securities
of any series shall then be due and payable as therein expressed or by
declaration of acceleration or otherwise and irrespective of whether the Trustee
shall have made any demand on the Company for the payment of overdue principal
(and premium, if any) or interest (including any Additional Interest)) shall be
entitled and empowered, by intervention in such proceeding or otherwise,

            (i)  to file and prove a claim for the whole amount of principal
     (or, if the Securities of that series are Discount Securities, such portion
     of the principal amount as may be due and payable pursuant to a declaration
     in accordance with Section 5.2) (and premium, if any) and interest
     (including any Additional Interest) owing and unpaid in respect to the
     Securities and to file such other papers or documents as may be necessary
     or advisable and to take any and all actions as are authorized under the
     Trust Indenture Act in order to have the claims of the Holders and any
     predecessor to the Trustee under Section 6.7 allowed in any such judicial
     proceedings; and

            (ii) in particular, the Trustee shall be authorized to collect and
     receive any moneys or other property payable or deliverable on any such
     claims and to distribute the same in accordance with Section 5.6; and

       (b) any custodian, receiver, assignee, trustee, liquidator, sequestrator
(or other similar official) in any such judicial proceeding is hereby authorized
by each Holder to make such payments to the Trustee for distribution in
accordance with Section 5.6, and in the event that the Trustee shall consent to
the making of such payments directly to the

                                      46
<PAGE>
 
Holders, to pay to the Trustee any amount due to it and any predecessor Trustee
under Section 6.7.

       Nothing herein contained shall be deemed to authorize the Trustee to
authorize or consent to or accept or adopt on behalf of any Holder any plan of
reorganization, arrangement, adjustment or composition affecting the Securities
or the rights of any Holder thereof, or to authorize the Trustee to vote in
respect of the claim of any Holder in any such proceeding; provided, however,
that the Trustee may, on behalf of the Holders, vote for the election of a
trustee in bankruptcy or similar official and be a member of a creditors' or
other similar committee.

       SECTION 5.5.   Trustee May Enforce Claims Without Possession of
Securities.

       All rights of action and claims under this Indenture or the Securities
may be prosecuted and enforced by the Trustee without the possession of any of
the Securities or the production thereof in any proceeding relating thereto, and
any such proceeding instituted by the Trustee shall be brought in its own name
as trustee of an express trust, and any recovery of judgment shall, after
provision for the payment of all the amounts owing the Trustee and any
predecessor Trustee under Section 6.7, its agents and counsel, be for the
ratable benefit of the Holders of the Securities in respect of which such
judgment has been recovered.

       SECTION 5.6.   Application of Money Collected.

       Any money or property collected or to be applied by the Trustee with
respect to a series of Securities pursuant to this Article shall be applied in
the following order, at the date or dates fixed by the Trustee and, in case of
the distribution of such money or property on account of principal (or premium,
if any) or interest (including any Additional Interest), upon presentation of
the Securities and the notation thereon of the payment if only partially paid
and upon surrender thereof if fully paid:

       FIRST:  To the payment of all amounts due the Trustee, its agents and
counsel and any predecessor Trustee, its agents and counsel under Section 6.7;

       SECOND:  Subject to Article XIII, to the payment of the amounts then due
and unpaid upon such series of Securities for principal (and premium, if any),
interest (including any Additional Interest) and Additional Taxes, in respect of
which or for the benefit of which such money has been collected, ratably,
without preference or priority of any kind, according to the amounts due and
payable on such series of Securities

                                      47
<PAGE>
 
for principal (and premium, if any) and interest (including any Additional
Interest), respectively; and

       THIRD:  The balance, if any, to the Person or Persons entitled thereto.

       SECTION 5.7.   Limitation on Suits.

       No Holder of any Securities of any series shall have any right to
institute any proceeding, judicial or otherwise, with respect to this Indenture
or for the appointment of a receiver, assignee, trustee, liquidator,
sequestrator (or other similar official) or for any other remedy hereunder,
unless:

       (1) such Holder has previously given written notice to the Trustee of a
continuing Event of Default with respect to the Securities of that series;

       (2) the Holders of not less than 25% in principal amount of the
Outstanding Securities of that series shall have made written request to the
Trustee to institute proceedings in respect of such Event of Default in its own
name as Trustee hereunder;

       (3) such Holder or Holders have offered to the Trustee reasonable
security or indemnity against the costs, expenses and liabilities to be incurred
in compliance with such request;

       (4) the Trustee for 60 days after its receipt of such notice, request and
offer of security or indemnity has failed to institute any such proceeding; and

       (5) no direction inconsistent with such written request has been given to
the Trustee during such 60-day period by the Holders of a majority in principal
amount of the Outstanding Securities of that series;

it being understood and intended that no one or more of such Holders shall have
any right in any manner whatever by virtue of, or by availing itself of, any
provision of this Indenture to affect, disturb or prejudice the rights of any
other Holders of Securities, or to obtain or to seek to obtain priority or
preference over any other of such Holders or to enforce any right under this
Indenture, except in the manner herein provided and for the equal and ratable
benefit of all such Holders.

                                      48
<PAGE>
 
       SECTION 5.8.  Unconditional Right of Holders to Receive Principal,
Premium and Interest; Direct Action by Holders of Preference Securities.

       Notwithstanding any other provision in this Indenture, the Holder of any
Security shall have the right which is absolute and unconditional to receive
payment of the principal of (and premium, if any) and (subject to Section 3.11)
interest (including any Additional Interest) on such Security on the respective
Stated Maturities expressed in such Security (or, in the case of redemption, on
the Redemption Date) and to institute suit for the enforcement of any such
payment, and such right shall not be impaired without the consent of such
Holder.  In the case of Securities of a series issued to an HL&P Trust, any
holder of the corresponding series of Preference Securities issued by such HL&P
Trust shall have the right, upon the occurrence of an Event of Default described
in Section 5.1(1) or 5.1(2), to institute a suit directly against the Company
for enforcement of payment to such holder of principal of (premium, if any) and
(subject to Section 3.11) interest (including any Additional Interest) on the
Securities having a principal amount equal to the aggregate Liquidation Amount
(as defined in the Trust Agreement under which such HL&P Trust is formed) of
such Preference Securities of the corresponding series held by such holder and
such right shall not be impaired without the consent of such Holder.

       SECTION 5.9.   Restoration of Rights and Remedies.

       If the Trustee, any Holder or any holder of Preference Securities has
instituted any proceeding to enforce any right or remedy under this Indenture
and such proceeding has been discontinued or abandoned for any reason, or has
been determined adversely to the Trustee, such Holder or such holder of
Preference Securities, then and in every such case the Company, the Trustee, the
Holders and such holder of Preference Securities shall, subject to any
determination in such proceeding, be restored severally and respectively to
their former positions hereunder, and thereafter all rights and remedies of the
Trustee, the Holders and the holders of Preference Securities shall continue as
though no such proceeding had been instituted.

       SECTION 5.10.  Rights and Remedies Cumulative.

       Except as otherwise provided in the last paragraph of Section 3.6, no
right or remedy herein conferred upon or reserved to the Trustee or to the
Holders is intended to be exclusive of any other right or remedy, and every
right and remedy shall, to the extent permitted by law, be cumulative and in
addition to every other right and remedy given hereunder or now or hereafter
existing at law or in equity or

                                      49
<PAGE>
 
otherwise.  The assertion or employment of any right or remedy hereunder, or
otherwise, shall not prevent the concurrent assertion or employment of any other
appropriate right or remedy.

       SECTION 5.11.  Delay or Omission Not Waiver.

       No delay or omission of the Trustee, any Holder of any Security or any
holder of any Preference Security to exercise any right or remedy accruing upon
any Event of Default shall impair any such right or remedy or constitute a
waiver of any such Event of Default or an acquiescence therein.

       Every right and remedy given by this Article or by law to the Trustee or
to the Holders and the right and remedy given to the holders of Preference
Securities by Section 5.8 may be exercised from time to time, and as often as
may be deemed expedient, by the Trustee, the Holders or the holders of
Preference Securities, as the case may be.

       SECTION 5.12.  Control by Holders.

       The Holders of a majority in principal amount of the Outstanding
Securities of any series shall have the right to direct the time, method and
place of conducting any proceeding for any remedy available to the Trustee or
exercising any trust or power conferred on the Trustee, with respect to the
Securities of such series, provided that:

       (1) such direction shall not be in conflict with any rule of law or with
this Indenture,

       (2) the Trustee may take any other action deemed proper by the Trustee
which is not inconsistent with such direction, and

       (3) subject to the provisions of Section 6.1, the Trustee shall have the
right to decline to follow such direction if a Responsible Officer or Officers
of the Trustee shall, in good faith, determine that the proceeding so directed
would involve the Trustee in personal liability or would otherwise be contrary
to applicable law.

       SECTION 5.13.  Waiver of Past Defaults.

       The Holders of not less than a majority in aggregate principal amount of
the Outstanding Securities of any series and, in the case of any Securities of a
series issued to an HL&P Trust, the holders of Preference Securities issued by
such HL&P Trust may waive any past default hereunder and its consequences with
respect to such series except a default:

                                      50
<PAGE>
 
       (1) in the payment of the principal of (or premium, if any) or interest
(including any Additional Interest) on any Security of such series, or

       (2) in respect of a covenant or provision hereof which under Article IX
cannot be modified or amended without the consent of the Holder of each
Outstanding Security of such series affected.

       Any such waiver shall be deemed to be on behalf of the Holders of all the
Securities of such series or, in the case of a waiver by holders of Preference
Securities issued by such HL&P Trust, by all holders of Preference Securities
issued by such HL&P Trust.

       Upon any such waiver, such default shall cease to exist, and any Event of
Default arising therefrom shall be deemed to have been cured, for every purpose
of this Indenture; but no such waiver shall extend to any subsequent or other
default or impair any right consequent thereon.

       SECTION 5.14.  Undertaking for Costs.

       All parties to this Indenture agree, and each Holder of any Security by
his acceptance thereof shall be deemed to have agreed, that any court may in its
discretion require, in any suit for the enforcement of any right or remedy under
this Indenture, or in any suit against the Trustee for my action taken or
omitted by it as Trustee, the filing by any party litigant in such suit of an
undertaking to pay the costs of such suit, and that such court may in its
discretion assess reasonable costs, including reasonable attorneys' fees and
expenses, against any party litigant in such suit, having due regard to the
merits and good faith of the claims or defenses made by such party litigant; but
the provisions of this Section shall not apply to any suit instituted by the
Trustee, to any suit instituted by any Holder, or group of Holders, holding in
the aggregate more than 10% in principal amount of the Outstanding Securities of
any series, or to any suit instituted by any Holder for the enforcement of the
payment of the principal of (or premium, if any) or interest (including any
Additional Interest) on any Security on or after the respective Stated
Maturities expressed in such Security.

       SECTION 5.15.  Waiver of Usury, Stay or Extension Laws.

       The Company covenants (to the extent that it may lawfully do so) that it
will not at any time insist upon, or plead, or in any manner whatsoever claim or
take the benefit or advantage of, any usury, stay or extension law wherever
enacted, now or at any time hereafter in force, which may affect the covenants
or the performance of this Indenture; and

                                      51
<PAGE>
 
the Company (to the extent that it may lawfully do so) hereby expressly waives
all benefit or advantage of any such law, and covenants that it will not hinder,
delay or impede the execution of any power herein granted to the Trustee, but
will suffer and permit the execution of every such power as though no such law
had been enacted.


                                   ARTICLE VI

                                  THE TRUSTEE

       SECTION 6.1.   Certain Duties and Responsibilities.

       (a)  Except during the continuance of an Event of Default,

            (1) the Trustee undertakes to perform such duties and only such
     duties as are specifically set forth in this Indenture, and no implied
     covenants or obligations shall be read into this Indenture against the
     Trustee; and

            (2) in the absence of bad faith on its part, the Trustee may
     conclusively rely, as to the truth of the statements and the correctness of
     the opinions expressed therein, upon certificates or opinions furnished to
     the Trustee and conforming to the requirements of this Indenture; but in
     the case of any such certificates or opinions which by any provisions
     hereof are specifically required to be furnished to the Trustee, the
     Trustee shall be under a duty to examine the same to determine whether or
     not they conform on their face to the requirements of this Indenture.

       (b)  In case an Event of Default has occurred and is continuing, the
Trustee shall exercise such of the rights and powers vested in it by this
Indenture, and use the same degree of care and skill in their exercise, as a
prudent person would exercise or use under the circumstances in the conduct of
his own affairs.

       (c)  No provision of this Indenture shall be construed to relieve the
Trustee from liability for its own negligent action, its own negligent failure
to act, or its own willful misconduct except that

            (1) this Subsection shall not be construed to limit the effect of
     Subsection (a) of this Section;

            (2) the Trustee shall not be liable for any error of judgment made
     in good faith by a Responsible

                                      52
<PAGE>
 
     Officer, unless it shall be proved that the Trustee was negligent in
     ascertaining the pertinent facts; and

            (3) the Trustee shall not be liable with respect to any action taken
     or omitted to be taken by it in good faith in accordance with the direction
     of Holders pursuant to Section 5.12 relating to the time, method and place
     of conducting any proceeding for any remedy available to the Trustee, or
     exercising any trust or power conferred upon the Trustee, under this
     Indenture with respect to the Securities of such series.

       (d)  No provision of this Indenture shall require the Trustee to expend
or risk its own funds or otherwise incur any financial liability in the
performance of any of its duties hereunder, or in the exercise of any of its
rights or powers, if there shall be reasonable grounds for believing that
repayment of such funds or adequate indemnity against such risk or liability is
not reasonably assured to it.

       (e)  Whether or not therein expressly so provided, every provision of
this Indenture relating to the conduct or affecting the liability of or
affording protection to the Trustee shall be subject to the provisions of this
Section.

       SECTION 6.2.   Notice of Defaults.

       Within 90 days after actual knowledge by a Responsible Officer of the
Trustee of the occurrence of any default hereunder with respect to the
Securities of any series, the Trustee shall transmit by mail to all Holders of
Securities of such series, as their names and addresses appear in the Securities
Register, notice of such default, unless such default shall have been cured or
waived; provided, however, that, except in the case of a default in the payment
of the principal of (or premium, if any) or interest (including any Additional
Interest) on any Security of such series, the Trustee shall be fully protected
in withholding such notice if and so long as a committee of Responsible Officers
of the Trustee in good faith determines that the withholding of such notice is
in the interests of the Holders of Securities of such series; and provided,
further, that, in the case of any default of the character specified in Section
5.1(3), no such notice to Holders of Securities of such series shall be given
until at least 30 days after the occurrence thereof.  For the purpose of this
Section, the term "default" means any event which is, or after notice or lapse
of time or both would become, an Event of Default with respect to Securities of
such series.

                                      53
<PAGE>
 
       SECTION 6.3.  Certain Rights of Trustee.

       Subject to the provisions of Section 6.1:

       (a) the Trustee may conclusively rely and shall be fully protected in
acting or refraining from acting upon any resolution, certificate, statement,
instrument, opinion, report, notice, request, direction, consent, order, bond,
debenture, Security or other paper or document believed by it to be genuine and
to have been signed or presented by the proper party or parties;

       (b) any request or direction of the Company mentioned herein shall be
sufficiently evidenced by a Company Request or Company Order and any resolution
of the Board of Directors shall be sufficiently evidenced by a Board Resolution;

       (c) whenever in the administration of this Indenture the Trustee shall
deem it desirable that a matter be proved or established prior to taking,
suffering or omitting any action hereunder, the Trustee (unless other evidence
be herein specifically prescribed) may, in the absence of bad faith on its part,
conclusively rely upon an Officers' Certificate;

       (d) the Trustee may consult with counsel of its selection and the advice
of such counsel or any Opinion of Counsel shall be full and complete
authorization and protection in respect of any action taken, suffered or omitted
by it hereunder in good faith and in reliance thereon;

       (e) the Trustee shall be under no obligation to exercise any of the
rights or powers vested in it by this Indenture at the request or direction of
any of the Holders pursuant to this Indenture, unless such Holders shall have
offered to the Trustee reasonable security or indemnity against the costs,
expenses and liabilities which might be incurred by it in compliance with such
request or direction;

       (f) the Trustee shall not be bound to make any investigation into the
facts or matters stated in any resolution, certificate, statement, instrument,
opinion, report, notice, request, direction, consent, order, bond, indenture,
Security or other paper or document, but the Trustee in its discretion may make
such inquiry or investigation into such facts or matters as it may see fit, and,
if the Trustee shall determine to make such inquiry or investigation, it shall
be entitled to examine the books, records and premises of the Company, upon
reasonable notice to the Company, during business hours, personally or by agent
or attorney; 

                                      54
<PAGE>
 
       (g) the Trustee may execute any of the trusts or powers hereunder or
perform any duties hereunder either directly or by or through agents or
attorneys and the Trustee shall not be responsible for any misconduct or
negligence on the part of any agent or attorney appointed with due care by it
hereunder.

       (h) the Trustee shall not be liable for any action taken, suffered, or 
omitted to be taken by it in good faith and reasonably believed by it to be 
authorized or within the discretion or rights or powers conferred upon it by 
this Indenture; and

       (i) the Trustee shall not be deemed to have notice of any Event of 
Default unless a Responsible Officer of the Trustee has actual knowledge thereof
or unless written notice of any event which is in fact such a default is 
received by the Trustee at the Corporate Trust Office of the Trustee, and such 
notice references the Securities and this Indenture.

       SECTION 6.4.   Not Responsible for Recitals or Issuance of Securities.

       The recitals contained herein and in the Securities, except the Trustee's
certificates of authentication, shall be taken as the statements of the Company,
and neither the Trustee nor any Authenticating Agent assumes any responsibility
for their correctness.  The Trustee makes no representations as to the validity
or sufficiency of this Indenture or of the Securities.  Neither the Trustee nor
any Authenticating Agent shall be accountable for the use or application by the
Company of the Securities or the proceeds thereof.

       SECTION 6.5.   May Hold Securities.

       The Trustee, any Authenticating Agent, any Paying Agent, any Securities
Registrar or any other agent of the Company, in its individual or any other
capacity, may become the owner or pledgee of Securities and, subject to Sections
6.8 and 6.13, may otherwise deal with the Company with the same rights it would
have if it were not Trustee, Authenticating Agent, Paying Agent, Securities
Registrar or such other agent.

       SECTION 6.6.   Money Held in Trust.

       Money held by the Trustee in trust hereunder need not be segregated from
other funds except to the extent required by law.  The Trustee shall be under no
liability for interest on any money received by it hereunder except as otherwise
agreed in writing with the Company.

       SECTION 6.7.   Compensation and Reimbursement.

       The Company agrees

       (1) to pay to the Trustee from time to time reasonable compensation for
all services rendered by it hereunder in such amounts as the Company and the
Trustee shall agree from time to time (which compensation shall not be limited
by any provision of law in regard to the compensation of a trustee of an express
trust);

       (2) to reimburse the Trustee upon its request for all reasonable
expenses, disbursements and advances incurred

                                      55
<PAGE>
 
or made by the Trustee in accordance with any provision of this Indenture
(including the reasonable compensation and the expenses and disbursements of its
agents and counsel), except any such expense, disbursement or advance as may be
attributable to its negligence or bad faith; and

       (3) to indemnify the Trustee, its officers, directors, shareholders,
employees and agents for, and to hold it harmless against, any and all loss,
damage, claim, liability or expense (including the reasonable compensation and
the expenses and disbursements of its agents and counsel) incurred without
negligence or bad faith, arising out of or in connection with the acceptance or
administration of this trust or the performance of its duties hereunder,
including the costs and expenses of defending itself against any claim or
liability in connection with the exercise or performance of any of its powers or
duties hereunder. This indemnification shall survive the termination of this
Indenture.

       This Section 6.7 shall survive the termination of this Indenture or the
earlier resignation or removal of the Trustee.

       To secure the Company's payment obligations in this Section, the Company
and the Holders agree that the Trustee shall have a lien prior to the Securities
on all money or property held or collected by the Trustee.  Such lien shall
survive the satisfaction and discharge of this Indenture.

       When the Trustee incurs expenses or renders services after an Event of
Default specified in Section 5.1(4) or (5) occurs, the expenses and the
compensation for the services are intended to constitute expenses of
administration under the Bankruptcy Reform Act of 1978 or any successor statute.

       SECTION 6.8.   Disqualification; Conflicting Interests.

       The Trustee for the Securities of any series issued hereunder shall be
subject to the provisions of Section 310(b) of the Trust Indenture Act.  Nothing
herein shall prevent the Trustee from filing with the Commission the application
referred to in the second to last paragraph of said Section 310(b).

       SECTION 6.9.   Corporate Trustee Required; Eligibility.

       There shall at all times be a Trustee hereunder which shall be

       (a) a corporation organized and doing business under the laws of the
United States of America or of any State

                                      56
<PAGE>
 
or Territory or the District of Columbia, authorized under such laws to exercise
corporate trust powers and subject to supervision or examination by Federal,
State, Territorial or District of Columbia authority, or

       (b) a corporation or other Person organized and doing business under the
laws of a foreign government that is permitted to act as Trustee pursuant to a
rule, regulation or order of the Commission, authorized under such laws to
exercise corporate trust powers, and subject to supervision or examination by
authority of such foreign government or a political subdivision thereof
substantially equivalent to supervision or examination applicable to United
States institutional trustees, in either case having a combined capital and
surplus of at least $50,000,000, subject to supervision or examination by
Federal or State authority.  If such corporation publishes reports of condition
at least annually, pursuant to law or to the requirements of the aforesaid
supervising or examining authority, then, for the purposes of this Section, the
combined capital and surplus of such corporation shall be deemed to be its
combined capital and surplus as set forth in its most recent report of condition
so published.  If at any time the Trustee shall cease to be eligible in
accordance with the provisions of this Section, it shall resign immediately in
the manner and with the effect hereinafter specified in this Article.  Neither
the Company nor any Person directly or indirectly controlling, controlled by or
under common control with the Company shall serve as Trustee for the Securities
of any series issued hereunder.

       SECTION 6.10.  Resignation and Removal; Appointment of Successor.

       (a) No resignation or removal of the Trustee and no appointment of a
successor Trustee pursuant to this Article shall become effective until the
acceptance of appointment by the successor Trustee under Section 6.11.

       (b) The Trustee may resign at any time with respect to the Securities of
one or more series by giving written notice thereof to the Company.  If an
instrument of acceptance by a successor Trustee shall not have been delivered to
the Trustee within 30 days after the giving of such notice of removal or
resignation, the Trustee being removed or resigning may petition, at the expense
of the Company, any court of competent jurisdiction for the appointment of a
successor Trustee with respect to the Securities of such series.

       (c) The Trustee may be removed at any time with respect to the Securities
of any series by Act of the Holders of a majority in principal amount of the
Outstanding Securities of such series, delivered to the Trustee and to the
Company.

                                      57
<PAGE>
 
       (d)  If at any time:

            (1) the Trustee shall fail to comply with Section 6.8 after written
     request therefor by the Company or by any Holder who has been a bona fide
     Holder of a Security for at least six months, or

            (2) the Trustee shall cease to be eligible under Section 6.9 and
     shall fail to resign after written request therefor by the Company or by
     any such Holder, or

            (3) the Trustee shall become incapable of acting or shall be
     adjudged a bankrupt or insolvent or a receiver of the Trustee or of its
     property shall be appointed or any public officer shall take charge or
     control of the Trustee or of its property or affairs for the purpose of
     rehabilitation, conservation or liquidation,

then, in any such case, (i) the Company, acting pursuant to the authority of a
Board Resolution, may remove the Trustee with respect to all Securities, or (ii)
subject to Section 5.14, any Holder who has been a bona fide Holder of a
Security for at least six months may, on behalf of himself and all others
similarly situated, petition any court of competent jurisdiction for the removal
of the Trustee with respect to all Securities and the appointment of a successor
Trustee or Trustees.

       (e) If the Trustee shall resign, be removed or become incapable of
acting, or if a vacancy shall occur in the office of Trustee for any cause with
respect to the Securities of one or more series, the Company, by a Board
Resolution, shall promptly appoint a successor Trustee with respect to the
Securities of that or those series.  If, within one year after such resignation,
removal or incapability, or the occurrence of such vacancy, a successor Trustee
with respect to the Securities of any series shall be appointed by Act of the
Holders of a majority in principal amount of the Outstanding Securities of such
series delivered to the Company and the retiring Trustee, the successor Trustee
so appointed shall, forthwith upon its acceptance of such appointment, become
the successor Trustee with respect to the Securities of such series and
supersede the successor Trustee appointed by the Company.  If no successor
Trustee with respect to the Securities of any series shall have been so
appointed by the Company or the Holders and accepted appointment in the manner
hereinafter provided, any Holder who has been a bona fide Holder of a Security
for at least six months may, subject to Section 5.14, on behalf of himself and
all others similarly situated, petition any court of competent jurisdiction for
the appointment of a successor Trustee with respect to the Securities of such
series.

                                      58
<PAGE>
 
          (f)  The Company shall give notice of each resignation and each
removal of the Trustee with respect to the Securities of any series and each
appointment of a successor Trustee with respect to the Securities of any series
by mailing written notice of such event by first-class mail, postage prepaid, to
the Holders of Securities of such series as their names and addresses appear in
the Securities Register. Each notice shall include the name of the successor
Trustee with respect to the Securities of such series and the address of its
Corporate Trust Office.

          SECTION 6.11.  Acceptance of Appointment by Successor.

          (a)  In case of the appointment hereunder of a successor Trustee with
respect to all Securities, every such successor Trustee so appointed shall
execute, acknowledge and deliver to the Company and to the retiring Trustee an
instrument accepting such appointment, and thereupon the resignation or removal
of the retiring Trustee shall become effective and such successor Trustee,
without any further act, deed or conveyance, shall become vested with all the
rights, powers, trusts and duties of the retiring Trustee; but, on the request
of the Company or the successor Trustee, such retiring Trustee shall, upon
payment of its charges, execute and deliver an instrument transferring to such
successor Trustee all the rights, powers and trusts of the retiring Trustee and
shall duly assign, transfer and deliver to such successor Trustee all property
and money held by such retiring Trustee hereunder.

          (b)  In case of the appointment hereunder of a successor Trustee with
respect to the Securities of one or more (but not all) series, the Company, the
retiring Trustee and each successor Trustee with respect to the Securities of
one or more series shall execute and deliver an indenture supplemental hereto
wherein each successor Trustee shall accept such appointment and which (1) shall
contain such provisions as shall be necessary or desirable to transfer and
confirm to, and to vest in, each successor Trustee all the rights, powers,
trusts and duties of the retiring Trustee with respect to the Securities of that
or those series to which the appointment of such successor Trustee relates, (2)
if the retiring Trustee is not retiring with respect to all Securities, shall
contain such provisions as shall be deemed necessary or desirable to confirm
that all the rights, powers, trusts and duties of the retiring Trustee with
respect to the Securities of that or those series as to which the retiring
Trustee is not retiring shall continue to be vested in the retiring Trustee, and
(3) shall add to or change any of the provisions of this Indenture as shall be
necessary to provide for or facilitate the administration of the trusts
hereunder by more than one Trustee, it being understood that nothing

                                      59
<PAGE>
 
herein or in such supplemental indenture shall constitute such Trustees co-
trustees of the same trust and that each such Trustee shall be trustee of a
trust or trusts hereunder separate and apart from any trust or trusts hereunder
administered by any other such Trustee; and upon the execution and delivery of
such supplemental indenture the resignation or removal of the retiring Trustee
shall become effective to the extent provided therein and each such successor
Trustee, without any further act, deed or conveyance, shall become vested with
all the rights, powers, trusts, and duties of the retiring Trustee with respect
to the Securities of that or those series to which the appointment of such
successor Trustee relates; but, on request of the Company or any successor
Trustee, such retiring Trustee shall duly assign, transfer and deliver to such
successor Trustee all property and money held by such retiring Trustee hereunder
with respect to the Securities of that or those series to which the appointment
of such successor Trustee relates.

          (c)  Upon request of any such successor Trustee, the Company shall
execute any and all instruments for more fully and certainly vesting in and
confirming to such successor Trustee all rights, powers and trusts referred to
in paragraph (a) or (b) of this Section, as the case may be.

          (d)  No successor Trustee shall accept its appointment unless at the
time of such acceptance such successor Trustee shall be qualified and eligible
under this Article.

          SECTION 6.12.  Merger, Conversion, Consolidation or Succession to
Business.

          Any corporation into which the Trustee may be merged or converted or
with which it may be consolidated, or any corporation resulting from any merger,
conversion or consolidation to which the Trustee shall be a party, or any
corporation succeeding to all or substantially all of the corporate trust
business of the Trustee, shall be the successor of the Trustee hereunder,
provided such corporation shall be otherwise qualified and eligible under this
Article, without the execution or filing of any paper or any further act on the
part of any of the parties hereto. In case any Securities shall have been
authenticated, but not delivered, by the Trustee then in office, any successor
by merger, conversion or consolidation to such authenticating Trustee may adopt
such authentication and deliver the Securities so authenticated, and in case any
Securities shall not have been authenticated, any successor to the Trustee may
authenticate such Securities either in the name of any predecessor Trustee or in
the name of such successor Trustee, and in all cases the certificate of
authentication shall have the full force which

                                      60
<PAGE>
 
it is provided anywhere in the Securities or in this Indenture that the
certificate of the Trustee shall have.

          SECTION 6.13.  Preferential Collection of Claims Against Company.

          If and when the Trustee shall be or become a creditor of the Company
(or any other obligor upon the Securities), the Trustee shall be subject to the
provisions of the Trust Indenture Act regarding the collection of claims against
the Company (or any such other obligor). For purposes of Section 311(b)(4) and
(6) of the Trust Indenture Act:

          (a)  "cash transaction" means any transaction in which full payment
for goods or securities sold is made within seven days after delivery of the
goods or securities in currency or in checks or other orders drawn upon banks
and payable upon demand; and

          (b)  "self-liquidating paper" means any draft, bill of exchange,
acceptance or obligation which is made, drawn, negotiated or incurred by the
Company (or any such obligor) for the purpose of financing the purchase,
processing, manufacturing, shipment, storage or sale of goods, wares or
merchandise and which is secured by documents evidencing title to, possession
of, or a lien upon, the goods, wares or merchandise or the receivables or
proceeds arising from the sale of the goods, wares or merchandise previously
constituting the security; provided the security is received by the Trustee
simultaneously with the creation of the creditor relationship with the Company
(or any such obligor) arising from the making, drawing, negotiating or incurring
of the draft, bill of exchange, acceptance or obligation.

          SECTION 6.14.  Appointment of Authenticating Agent.

          The Trustee may appoint an Authenticating Agent or Agents with respect
to one or more series of Securities which shall be authorized to act on behalf
of the Trustee to authenticate Securities of such series issued upon original
issue and upon exchange, registration of transfer or partial redemption thereof
or pursuant to Section 3.6, and Securities so authenticated shall be entitled to
the benefits of this Indenture and shall be valid and obligatory for all
purposes as if authenticated by the Trustee hereunder. Wherever reference is
made in this Indenture to the authentication and delivery of Securities by the
Trustee or the Trustee's certificate of authentication, such reference shall be
deemed to include authentication and delivery on behalf of the Trustee by an
Authenticating Agent. Each Authenticating Agent shall be acceptable to the
Company and shall at all times be a corporation organized and doing business
under the laws of the United States of America, or of any State or Territory or

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<PAGE>
 
the District of Columbia, authorized under such laws to act as Authenticating
Agent, having a combined capital and surplus of not less than $50,000,000 and
subject to supervision or examination by Federal or State authority.  If such
Authenticating Agent publishes reports of condition at least annually, pursuant
to law or to the requirements of said supervising or examining authority, then
for the purposes of this Section the combined capital and surplus of such
Authenticating Agent shall be deemed to be its combined capital and surplus as
set forth in its most recent report of condition so published.  If at any time
an Authenticating Agent shall cease to be eligible in accordance with the
provisions of this Section, such Authenticating Agent shall resign immediately
in the manner and with the effect specified in this Section.

          Any corporation into which an Authenticating Agent may be merged or
converted or with which it may be consolidated, or any corporation resulting
from any merger, conversion or consolidation to which such Authenticating Agent
shall be a party, or any corporation succeeding to all or substantially all of
the corporate trust business of an Authenticating Agent shall be the successor
Authenticating Agent hereunder, provided such corporation shall be otherwise
eligible under this Section, without the execution or filing of any paper or any
further act on the part of the Trustee or the Authenticating Agent.

          An Authenticating Agent may resign at any time by giving written
notice thereof to the Trustee and to the Company. The Trustee may at any time
terminate the agency of an Authenticating Agent by giving written notice thereof
to such Authenticating Agent and to the Company. Upon receiving such a notice of
resignation or upon such a termination, or in case at any time such
Authenticating Agent shall cease to be eligible in accordance with the
provisions of this Section, the Trustee may appoint a successor Authenticating
Agent which shall be acceptable to the Company and shall give notice of such
appointment in the manner provided in Section 1.6 to all Holders of Securities
of the series with respect to which such Authenticating Agent will serve. Any
successor Authenticating Agent upon acceptance of its appointment hereunder
shall become vested with all the rights, powers and duties of its predecessor
hereunder, with like effect as if originally named as an Authenticating Agent.
No successor Authenticating Agent shall be appointed unless eligible under the
provision of this Section.

          The Company agrees to pay to each Authenticating Agent from time to
time reasonable compensation for its services under this Section.

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<PAGE>
 
          If an appointment with respect to one or more series is made pursuant
to this Section, the Securities of such series may have endorsed thereon, in
addition to the Trustee's certificate of authentication, an alternative
certificate of authentication in the following form:

          This is one of the Securities referred to in the within mentioned
Indenture.

Dated:

                                        The Bank of New York,
                                             As Trustee


                                             By:
                                             As Authenticating Agent
                               
                               
                                             By:
                                                  Authorized Officer


                                  ARTICLE VII

               HOLDER'S LISTS AND REPORTS BY TRUSTEE AND COMPANY

          SECTION 7.1.  Company to Furnish Trustee Names and Addresses of
Holders.

The Company will furnish or cause to be furnished to the Trustee:

          (a)  semi-annually, not more than 15 days after [____________ 15] in
each year, a list, in such form as the Trustee may reasonably require, of the
names and addresses of the Holders as of such [_____________ 15,] and

          (b)  at such other times as the Trustee may request in writing, within
30 days after the receipt by the Company of any such request, a list of similar
form and content as of a date not more than 15 days prior to the time such list
is furnished, 

          excluding from any such list names and addresses received by the
Trustee in its capacity as Securities Registrar.

          SECTION 7.2.  Preservation of Information, Communications to Holders.

          (a)  The Trustee shall preserve, in as current a form as is reasonably
practicable, the names and addresses of Holders contained in the most recent
list furnished to the

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<PAGE>
 
Trustee as provided in Section 7.1 and the names and addresses of Holders
received by the Trustee in its capacity as Securities Registrar.  The Trustee
may destroy any list furnished to it as provided in Section 7.1 upon receipt of
a new list so furnished.

          (b)  The rights of Holders to communicate with other Holders with
respect to their rights under this Indenture or under the Securities, and the
corresponding rights and privileges of the Trustee, shall be as provided in the
Trust Indenture Act.

          (c)  Every Holder of Securities, by receiving and holding the same,
agrees with the Company and the Trustee that neither the Company nor the Trustee
nor any agent of either of them shall be held accountable by reason of the
disclosure of information as to the names and addresses of the Holders made
pursuant to the Trust Indenture Act.

          SECTION 7.3.  Reports by Trustee.

          (a)  The Trustee shall transmit to Holders such reports concerning the
Trustee and its actions under this Indenture as may be required pursuant to the
Trust Indenture Act, at the times and in the manner provided pursuant thereto.

          (b)  Reports so required to be transmitted at stated intervals of not
more than 12 months shall be transmitted no later than March 31 in each calendar
year, commencing with the first March 31 after the first issuance of Securities
under this Indenture.

          (c)  A copy of each such report shall, at the time of such
transmission to Holders, be filed by the Trustee with each stock exchange upon
which any Securities are listed and also with the Commission. The Company will
promptly notify the Trustee when any Securities are listed on any stock
exchange.

          SECTION 7.4.  Reports by Company.

          The Company shall file with the Trustee and with the Commission, and
transmit to Holders, such information, documents and other reports, and such
summaries thereof, as may be required pursuant to the Trust Indenture Act at the
times and in the manner provided in the Trust Indenture Act; provided that any
such information, documents or reports required to be filed with the Commission
pursuant to Section 13 or Section 15(d) of the Exchange Act shall be filed with
the Trustee within 15 days after the same is required to be filed with the
Commission.  Notwithstanding that the Company may not be required to remain
subject to the reporting requirements of Section 13 or 15(d) of the Exchange
Act, the Company shall continue to file with the Commission and provide

                                      64
<PAGE>
 
the Trustee with the annual reports and the information, documents and other
reports which are specified in Sections 13 and 15(d) of the Exchange Act.  The
Company also shall comply with the other provisions of Trust Indenture Act
Section 314(a).

Delivery of such reports, information and documents to the Trustee is for 
informational purposes only and the Trustee's receipt of such shall not 
constitute constructive notice of any information contained therein or 
determinable from information contained therein, including the Company's 
compliance with any of its covenants hereunder (as to which the Trustee is 
entitled to rely exclusively on Officers' Certificates).


                                  ARTICLE VIII

              CONSOLIDATION, MERGER, CONVEYANCE, TRANSFER OR LEASE

          SECTION 8.1.  Company May Consolidate, Etc., Only on Certain Terms.

          The Company shall not consolidate with or merge into any other Person
or convey, transfer or lease its properties and assets substantially as an
entirety to any Person, and no Person shall consolidate with or merge into the
Company or convey, transfer or lease its properties and assets substantially as
an entirety to the Company, unless:

          (1)  in case the Company shall consolidate with or merge into another
Person or convey, transfer or lease its properties and assets substantially as
an entirety to any Person, the Person formed by such consolidation or into which
the Company is merged or the Person which acquires by conveyance or transfer, or
which leases, the properties and assets of the Company substantially as an
entirety shall be a corporation, partnership or trust organized and existing
under the laws of the United States of America or any State or the District of
Columbia and shall expressly assume, by an indenture supplemental hereto,
executed and delivered to the Trustee, in form satisfactory to the Trustee, the
due and punctual payment of the principal of (and premium, if any) and interest
(including any Additional Interest) on all the Securities and the performance of
every covenant of this Indenture on the part of the Company to be performed or
observed;

          (2)  immediately after giving effect to such transaction, no Event of
Default, and no event which, after notice or lapse of time, or both, would
become an Event of Default, shall have happened and be continuing;

          (3)  in the case of the Securities of a series issued to an HL&P
Trust, such consolidation, merger, conveyance, transfer or lease is permitted
under the related Trust Agreement and HL&P Guarantee and does not give rise to
any breach or violation of the related Trust Agreement or HL&P Guarantee; and

          (4)  the Company has delivered to the Trustee an Officers' Certificate
and an Opinion of Counsel, each stating

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<PAGE>
 
that such consolidation, merger, conveyance, transfer or lease and any such
supplemental indenture complies with this Article and that all conditions
precedent herein provided for relating to such transaction have been complied
with; and the Trustee, subject to Section 6.1, may rely upon such Officers'
Certificate and Opinion of Counsel as conclusive evidence that such transaction
complies with this Section 8.1.

          SECTION 8.2.  Successor Corporation Substituted.

          Upon any consolidation or merger by the Company with or into any other
Person, or any conveyance, transfer or lease by the Company of its properties
and assets substantially as an entirety to any Person in accordance with Section
8.1, the successor Person formed by such consolidation or into which the Company
is merged or to which such conveyance, transfer or lease is made shall succeed
to, and be substituted for, and may exercise every right and power of, the
Company under this Indenture with the same effect as if such successor Person
had been named as the Company herein; and in the event of any such conveyance,
transfer or lease the Company shall be discharged from all obligations and
covenants under the Indenture and the Securities and may be dissolved and
liquidated.

          Such successor Person may cause to be signed, and may issue either in
its own name or in the name of the Company, any or all of the Securities
issuable hereunder which theretofore shall not have been signed by the Company
and delivered to the Trustee; and, upon the order of such successor Person
instead of the Company and subject to all the terms, conditions and limitations
in this Indenture prescribed, the Trustee shall authenticate and shall deliver
any Securities which previously shall have been signed and delivered by the
officers of the Company to the Trustee for authentication pursuant to such
provisions and any Securities which such successor Person thereafter shall cause
to be signed and delivered to the Trustee on its behalf for the purpose pursuant
to such provisions. All the Securities so issued shall in all respects have the
same legal rank and benefit under this Indenture as the Securities theretofore
or thereafter issued in accordance with the terms of this Indenture as though
all of such Securities had been issued at the date of the execution hereof.

          In case of any such consolidation, merger, sale, conveyance or lease,
such changes in phraseology and form may be made in the Securities thereafter to
be issued as may be appropriate.

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<PAGE>
 
                                  ARTICLE IX

                            SUPPLEMENTAL INDENTURES

          SECTION 9.1.  Supplemental Indentures without Consent of Holders.

          Without the consent of any Holders, the Company, when authorized by a
Board Resolution, and the Trustee, at any time and from time to time, may enter
into one or more indentures supplemental hereto, in form satisfactory to the
Trustee, for any of the following purposes:

          (1)  to evidence the succession of another Person to the Company, and
the assumption by any such successor of the covenants of the Company herein and
in the Securities contained; or

          (2)  to convey, transfer, assign, mortgage or pledge any property to
or with the Trustee or to surrender any right or power herein conferred upon the
Company; or

          (3)  to establish the form or terms of Securities of any series as
permitted by Section 2.1 or 3.1; or

          (4)  to add to the covenants of the Company for the benefit of the
Holders of all or any series of Securities (and if such covenants are to be for
the benefit of less than all series of Securities, stating that such covenants
are expressly being included solely for the benefit of such series) or to
surrender any right or power herein conferred upon the Company; or

          (5)  to add any additional Events of Default for the benefit of the
Holders of all or any series of Securities (and if such additional Events of
Default are to be for the benefit of less than all series of Securities, stating
that such additional Events of Default are expressly being included solely for
the benefit of such series); or

          (6)  to change or eliminate any of the provisions of this Indenture,
provided that any such change or elimination shall become effective only when
there is no Security Outstanding of any series created prior to the execution of
such supplemental indenture which is entitled to the benefit of such provision;
or

          (7)  to cure any ambiguity, to correct or supplement any provision
herein which may be defective or inconsistent with any other provision herein,
or to make any other provisions with respect to matters or questions arising
under this Indenture, provided that such action pursuant to this clause (7)
shall not adversely affect the interest of the

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<PAGE>
 
Holders of Securities of any series in any material respect or, in the case of
the Securities of a series issued to an HL&P Trust and for so long as any of the
corresponding series of Preference Securities issued by such HL&P Trust shall
remain outstanding, the holders of such Preference Securities; or

          (8)  to evidence and provide for the acceptance of appointment
hereunder by a successor Trustee with respect to the Securities of one or more
series and to add to or change any of the provisions of this Indenture as shall
be necessary to provide for or facilitate the administration of the trusts
hereunder by more than one Trustee, pursuant to the requirements of Section 6.11
(b); or

          (9)  to comply with the requirements of the Commission in order to
effect or maintain the qualification of this Indenture under the Trust Indenture
Act.

          SECTION 9.2.  Supplemental Indentures with Consent of Holders.

          With the consent of the Holders of not less than a majority in
principal amount of the Outstanding Securities of each series affected by such
supplemental indenture, by Act of said Holders delivered to the Company and the
Trustee, the Company, when authorized by a Board Resolution, and the Trustee may
enter into an indenture or indentures supplemental hereto for the purpose of
adding any provisions to or changing in any manner or eliminating any of the
provisions of this Indenture or of modifying in any manner the rights of the
Holders of Securities of such series under this Indenture; provided, however,
that no such supplemental indenture shall, without the consent of the Holder of
each Outstanding Security affected thereby,

          (1)  except to the extent permitted by Section 3.11 or as otherwise
specified as contemplated by Section 2.1 or Section 3.1 with respect to the
deferral of the payment of interest on the Securities of any series and except
to the extent permitted by Section 3.14 or as otherwise specified as
contemplated by Section 2.1 or Section 3.1 with respect to the advancing or
extension of Stated Maturity of the Securities of any Series, change the Stated
Maturity of the principal of, or any installment of interest (including any
Additional Interest) on, any Security, or reduce the principal amount thereof or
the rate of interest thereon or reduce any premium payable upon the redemption
thereof, or reduce the amount of principal of a Discount Security that would be
due and payable upon a declaration of acceleration of the Maturity thereof
pursuant to Section 5.2, or change the place of payment where, or the coin or
currency in which, any Security or interest thereon is payable, or impair the
right to institute suit for

                                      68
<PAGE>
 
the enforcement of any such payment on or after the Stated Maturity thereof (or,
in the case of redemption, on or after the Redemption Date), or

          (2)  reduce the percentage in principal amount of the Outstanding
Securities of any series, the consent of whose Holders is required for any such
supplemental indenture, or the consent of whose Holders is required for any
waiver (of compliance with certain provisions of this Indenture or certain
defaults hereunder and their consequences) provided for in this Indenture, or

          (3)  modify any of the provisions of this Section, Section 5.13 or
Section 10.5, except to increase any such percentage or to provide that certain
other provisions of this Indenture cannot be modified or waived without the
consent of the Holder of each Security affected thereby; or

          (4)  modify the provisions in Article XIII of this Indenture with
respect to the subordination of Outstanding Securities of any series in a manner
adverse to the Holders thereof; 

provided, further, that, in the case of the Securities of a series issued to an
HL&P Trust, so long as any of the corresponding series of Preference Securities
issued by such HL&P Trust remains outstanding, (i) no such amendment shall be
made that adversely affects the holders of such Preference Securities in any
material respect, and no termination of this Indenture shall occur, and no
waiver of any Event of Default or compliance with any covenant under this
Indenture shall be effective, without the prior consent of the holders of at
least a majority of the aggregate Liquidation Amount (as defined in the Trust
Agreement under which such HL&P Trust is organized) of such Preference
Securities then outstanding unless and until the principal (and premium, if any)
of the Securities of such series and all accrued and, subject to Section 3.7,
unpaid interest (including any Additional Interest) thereon have been paid in
full and (ii) no such amendment shall be made where a consent under this
Indenture would require the consent of each holder of Securities, unless each
holder of Preference Securities, which corresponds to such series of Securities,
also consents to such amendment, unless and until the principal (and premium, if
any) of the Securities of such series and all accrued and (subject to Section
3.7) unpaid interest (including any Additional Interest) thereon have been paid
in full.

          A supplemental indenture that changes or eliminates any covenant or
other provision of this Indenture that has expressly been included solely for
the benefit of one or more particular series of Securities or Preference
Securities, or which modifies the rights of the Holders of Securities or

                                      69
<PAGE>
 
holders of Preference Securities of such series with respect to such covenant or
other provision, shall be deemed not to affect the rights under this Indenture
of the Holders of Securities or holders of Preference Securities of any other
series.

          It shall not be necessary for any Act of Holders under this Section to
approve the particular form of any proposed supplemental indenture, but it shall
be sufficient if such Act shall approve the substance thereof.

          SECTION 9.3.  Execution of Supplemental Indentures.

          In executing or accepting the additional trusts created by any
supplemental indenture permitted by this Article or the modifications thereby of
the trusts created by this Indenture, the Trustee shall be entitled to receive,
and (subject to Section 6.1) shall be fully protected in conclusively relying
upon, an Officers' Certificate and an Opinion of Counsel stating that the
execution of such supplemental indenture is authorized or permitted by this
Indenture, and that all conditions precedent have been complied with.  The
Trustee may, but shall not be obligated to, enter into any such supplemental
indenture which affects the Trustee's own rights, duties or immunities under
this Indenture or otherwise.

          SECTION 9.4.  Effect of Supplemental Indentures.

          Upon the execution of any supplemental indenture under this Article,
this Indenture shall be modified in accordance therewith, and such supplemental
indenture shall form a part of this Indenture for all purposes; and every Holder
of Securities theretofore or thereafter authenticated and delivered hereunder
shall be bound thereby.

          SECTION 9.5.  Conformity with Trust Indenture Act.

          Every supplemental indenture executed pursuant to this Article shall
conform to the requirements of the Trust Indenture Act as then in effect.

          SECTION 9.6.  Reference in Securities to Supplemental Indentures.

          Securities authenticated and delivered after the execution of any
supplemental indenture pursuant to this Article may, and shall if required by
the Company, bear a notation in form approved by the Company as to any matter
provided for in such supplemental indenture.  If the Company shall so determine,
new Securities of any series so modified as to conform, in the opinion of the
Company, to any such supplemental indenture may be prepared and executed by the

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<PAGE>
 
Company and authenticated and delivered by the Trustee in exchange for
Outstanding Securities of such series.


                                   ARTICLE X

                                   COVENANTS

          SECTION 10.1.  Payment of Principal, Premium and Interest.

          The Company covenants and agrees for the benefit of each series of
securities that it will duly and punctually pay the principal of (and premium,
if any) and interest (including Additional Interest) on the Securities of that
series in accordance with the terms of such Securities and this Indenture.

          SECTION 10.2.  Maintenance of Office or Agency.

          The Company will maintain in each Place of Payment for any series of
Securities, an office or agency where Securities of that series may be presented
or surrendered for payment and an office or agency where Securities of that
series may be surrendered for transfer or exchange and where notices and demands
to or upon the Company in respect of the Securities of that series and this
Indenture may be served.  The Company initially appoints the Trustee, acting
through its Corporate Trust Office, as its agent for said purposes.  The Company
will give prompt written notice to the Trustee of any change in the location of
any such office or agency.  If at any time the Company shall fail to maintain
such office or agency or shall fail to furnish the Trustee with the address
thereof, such presentations, surrenders, notices and demands may be made or
served at the Corporate Trust Office of the Trustee, and the Company hereby
appoints the Trustee as its agent to receive all such presentations, surrenders,
notices and demands.

          The Company may also from time to time designate one or more other
offices or agencies where the Securities may be presented or surrendered for any
or all of such purposes, and may from time to time rescind such designations;
provided, however, that no such designation or rescission shall in any manner
relieve the Company of its obligation to maintain an office or agency in each
Place of Payment for Securities of any series for such purposes.  The Company
will give prompt written notice to the Trustee of any such designation and any
change in the location of any such office or agency.

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<PAGE>
 
          SECTION 10.3.  Money for Security Payments to be Held in Trust.

          If the Company shall at any time act as its own Paying Agent with
respect to any series of Securities, it will, on or before each due date of the
principal of (and premium, if any) or interest (and any Additional Interest) on
any of the Securities of such series, segregate and hold in trust for the
benefit of the Persons entitled thereto a sum sufficient to pay the principal
(and premium, if any) or interest (and any Additional Interest) so becoming due
until such sums shall be paid to such Persons or otherwise disposed of as herein
provided, and will promptly notify the Trustee of its failure so to act.

          Whenever the Company shall have one or more Paying Agents, it will,
prior to 11:00 a.m. New York City time on each due date of the principal of or
interest (and any Additional Interest) on any Securities, deposit with a Paying
Agent a sum sufficient to pay the principal (and premium, if any) or interest
(and any Additional Interest) so becoming due, such sum to be held in trust for
the benefit of the Persons entitled to such principal and premium (if any) or
interest (and any Additional Interest), and (unless such Paying Agent is the
Trustee) the Company will promptly notify the Trustee of its failure so to act.

          The Company will cause each Paying Agent other than the Trustee to
execute and deliver to the Trustee an instrument in which such Paying Agent
shall agree with the Trustee, subject to the provisions of this Section, that
such Paying Agent will:

          (1)  hold all sums held by it for the payment of the principal of (and
premium, if any) or interest (including Additional Interest) on Securities in
trust for the benefit of the Persons entitled thereto until such sums shall be
paid to such Persons or otherwise disposed of as herein provided;

          (2)  give the Trustee notice of any default by the Company (or any
other obligor upon the Securities) in the making of any payment of principal
(and premium, if any) or interest (including Additional Interest);

          (3)  at any time during the continuance of any such default, upon the
written request of the Trustee, forthwith pay to the Trustee all sums so held in
trust by such Paying Agent; and

          (4)  comply with the provisions of the Trust Indenture Act applicable
to it as a Paying Agent.

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<PAGE>
 
          The Company may at any time, for the purpose of obtaining the
satisfaction and discharge of this Indenture or for any other purpose, pay, or
by Company Order direct any Paying Agent to pay, to the Trustee all sums held in
trust by the Company or such Paying Agent, such sums to be held by the Trustee
upon the same trusts as those upon which such sums were held by the Company or
such Paying Agent; and, upon such payment by any Paying Agent to the Trustee,
such Paying Agent shall be released from all further liability with respect to
such money.

          Any money deposited with the Trustee or any Paying Agent, or then held
by the Company, in trust for the payment of the principal of (and premium, if
any) or interest (including Additional Interest) on any Security and remaining
unclaimed for two years after such principal (and premium, if any) or interest
has become due and payable shall (unless otherwise required by mandatory
provision of applicable escheat or abandoned or unclaimed property law) be paid
on Company Request to the Company, or (if then held by the Company) shall
(unless otherwise required by mandatory provision of applicable escheat or
abandoned or unclaimed property law) be discharged from such trust; and the
Holder of such Security shall thereafter, as an unsecured general creditor, look
only to the Company for payment thereof, and all liability of the Trustee, its
officers, directors, shareholders employees and agents or such Paying Agent with
respect to such trust money, and all liability of the Company as trustee
thereof, shall thereupon cease; provided, however, that the Trustee or such
Paying Agent, before being required to make any such repayment, may at the
expense of the Company cause to be published once, in a newspaper published in
the English language, customarily published on each Business Day and of general
circulation in the Borough of Manhattan, The City of New York, notice that such
money remains unclaimed and that, after a date specified therein, which shall
not be less than 30 days from the date of such publication, any unclaimed
balance of such money then remaining will be repaid to the Company.

          SECTION 10.4.  Statement as to Compliance.

          The Company shall deliver to the Trustee, within 120 days after the
end of each calendar year of the Company ending after the date hereof, an
Officers' Certificate covering the preceding calendar year, stating whether or
not to the best knowledge of the signers thereof the Company, are of the signers
of which shall be the principal executive, principal accounting or principal
financial officer of the Company, is in default in the performance, observance
or fulfillment of or compliance with any of the terms, provisions, covenants and
conditions of this Indenture, and if the Company shall be in default, specifying
all such defaults and the nature and status thereof of which they may have
knowledge. For the purpose of this Section 10.4, compliance shall be determined
without regard to

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<PAGE>
 
any grace period or requirement of notice provided pursuant to the terms of this
Indenture.

          SECTION 10.5.  Waiver of Certain Covenants.

          The Company may omit in any particular instance to comply with any
covenant or condition provided pursuant to Section 3.1, 9.1(3) or 9.1(4) with
respect to the Securities of any series, if before or after the time for such
compliance the Holders of at least a majority in principal amount of the
Outstanding Securities of such series shall, by Act of such Holders, either
waive such compliance in such instance or generally waive compliance with such
covenant or condition, but no such waiver shall extend to or affect such
covenant or condition except to the extent so expressly waived, and, until such
waiver shall become effective, the obligations of the Company in respect of any
such covenant or condition shall remain in full force and effect.

          SECTION 10.6.  Additional Sums.

          In the case of the Securities of a series issued to an HL&P Trust, so
long as no Event of Default has occurred and is continuing and except as
otherwise specified as contemplated by Section 2.1 or Section 3.1, in the event
that (i) an HL&P Trust is the Holder of all of the Outstanding Securities of
such series, (ii) a Tax Event or an Investment Company Act Event in respect of
such HL&P Trust shall have occurred and be continuing and (iii) the Company
shall not have (A) redeemed the Securities of such series pursuant to Section 11
and the applicable supplemental indenture or (B) terminated such HL&P Trust
pursuant to Section 9.2(b) of the related Trust Agreement, the Company shall pay
to such HL&P Trust (and its permitted successors or assigns under the related
Trust Agreement) for so long as such HL&P Trust (or its permitted successor or
assignee) is the registered holder of any Securities of such series, such
additional amounts as may be necessary in order that the amount of Distributions
(including any Additional Amounts (as defined in such Trust Agreement)) then due
and payable by such HL&P Trust on the related Preference Securities and Common
Securities that at any time remain outstanding in accordance with the terms
thereof shall not be reduced as a result of any Additional Taxes (the
"Additional Sums").  Whenever in this Indenture or the Securities there is a
reference in any context to the payment of principal of or interest on the
Securities, such mention shall be deemed to include mention of the payments of
the Additional Sums provided for in this paragraph to the extent that, in such
context, Additional Sums are, were or would be payable in respect thereof
pursuant to the provisions of this paragraph and express mention of the payment
of Additional Sums (if applicable) in any provisions hereof shall not be
construed as excluding Additional Sums in those

                                      74
<PAGE>
 
provisions hereof where such express mention is not made; provided, however,
that the deferral of the payment of interest pursuant to Section 3.11 on the
Securities shall not defer the payment of any Additional Sums that may be due
and payable.

          SECTION 10.7.  Additional Covenants.

          The Company covenants and agrees with each Holder of Securities of
each series that it shall not, (i) declare or pay any dividends or distributions
on, or redeem, purchase, acquire or make a liquidation payment with respect to,
any of the Company's capital stock, or (ii) make any payment of principal of or
interest or premium, if any, on or repay, repurchase or redeem any debt security
(including other series of the Securities) of the Company that, in either case,
ranks pari passu with or junior in interest to the Securities of such series or
make any guarantee payments with respect to any guarantee by the Company of the
debt securities of any subsidiary of the Company if such guarantee ranks pari
passu with or junior in interest to the Securities (other than (a) dividends or
distributions in capital stock of the Company, (b) any declaration of a dividend
under a Rights Plan or in connection with the implementation of a Rights Plan,
the issuance of capital stock of the Company under a Rights Plan or the
redemption or repurchase of any rights distributed pursuant to a Rights Plan,
(c) payments under any HL&P Guarantee, and (d) purchases of Common Stock related
to the issuance of Common Stock or rights under any of the Company's benefit
plans for its directors, officers or employees, related to the issuance of
Common Stock or rights under a dividend reinvestment and stock purchase plan or
related to the issuance of Common Stock (or securities convertible into or
exchangeable for Common Stock) as consideration in an acquisition transaction
that was entered into prior to the commencement of such Extension Period) if at
such time (i) an Event of Default with respect to the Securities of such series
shall have occurred and be continuing, (ii) if the Securities of such series are
held by an HL&P Trust, the Company shall be in default with respect to its
payment of any obligations under the HL&P Guarantee relating to the Preference
Securities issued by such HL&P Trust or (iii) the Company shall have given
notice of its election to begin an Extension Period with respect to the
Securities of such series as provided herein and shall not

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<PAGE>
 
have rescinded such notice, or such Extension Period, or any extension thereof,
shall be continuing.

          The Company also covenants with each Holder of Securities of a series
issued to an HL&P Trust (i) to maintain directly or indirectly 100% ownership of
the Common Securities of such HL&P Trust; provided, however, that any permitted
successor of the Company hereunder may succeed to the Company's ownership of
such Common Securities, (ii) not to voluntarily terminate, wind-up or liquidate
such HL&P Trust, except (a) in connection with a distribution of the Securities
of such series to the holders of the Trust Securities in liquidation of such
HL&P Trust or (b) in connection with certain mergers, consolidations or
amalgamations permitted by the related Trust Agreement and (iii) to use its
reasonable efforts, consistent with the terms and provisions of such Trust
Agreement, to cause such HL&P Trust to remain classified as a grantor trust and
not an association taxable as a corporation for United States federal income tax
purposes.

          Section 10.8.  Calculation of Original Issue Discount.

          The Company shall file with the Trustee promptly at the end of each 
calendar year (i) a written notice specifying the amount of original issue 
discount (including daily rates and accrual periods) accrued on Outstanding 
Securities as of the end of such year and (ii) such other specific information 
relating to such original issue discount as may then be relevant under the 
Internal Revenue Code of 1986, as amended from time to time.


                                   ARTICLE XI

                            REDEMPTION OF SECURITIES

          SECTION 11.1.  Applicability of This Article.

          Redemption of Securities of any series (whether by operation of a
sinking fund or otherwise) as permitted or required by any form of Security
issued pursuant to this Indenture shall be made in accordance with such form of
Security and this Article; provided, however, that if any provision of any such
form of Security shall conflict with any provision of this Article, the
provision of such form of Security shall govern. Each Security of such series
shall be subject to partial redemption only as set forth in the form of Security
for such series.

          SECTION 11.2.  Election to Redeem; Notice to Trustee.

          The election of the Company to redeem any Securities shall be
evidenced by or pursuant to a Board Resolution. In case of any redemption at the
election of the Company of any Securities of a series, the Company shall, not
less than 30 nor more than 60 days prior to the Redemption Date (unless a
shorter notice shall be satisfactory to the Trustee), notify the Trustee of such
date and of the principal amount of Securities of that series to be redeemed. In
the case of any redemption of Securities prior to the expiration of any
restriction on such redemption provided in the terms of such Securities, the
Company shall furnish the Trustee with an

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<PAGE>
 
Officers' Certificate and an Opinion of Counsel evidencing compliance with such
restriction.

          SECTION 11.3.  Selection of Securities to be Redeemed.

          If less than all the Securities of any series are to be redeemed
(unless all the Securities of such series and of a specified tenor are to be
redeemed or unless such redemption affects only a single Security), the
particular Securities to be redeemed shall be selected not more than 60 days
prior to the Redemption Date by the Trustee, from the Outstanding Securities of
such series not previously called for redemption, by such method as the Trustee
shall deem fair and appropriate and which may provide for the selection for
redemption of a portion of the principal amount of any Security of such series,
provided that the unredeemed portion of the principal amount of any Security
shall be in an authorized denomination (which shall not be less than the minimum
authorized denomination) for such Security. If less than all the Securities of
such series and of a specified tenor are to be redeemed (unless such redemption
affects only a single Security), the particular Securities to be redeemed shall
be selected not more than 60 days prior to the Redemption Date by the Trustee,
from the Outstanding Securities of such series and specified tenor not
previously called for redemption in accordance with the preceding sentence.

          The Trustee shall promptly notify the Company in writing of the
Securities selected for partial redemption and the principal amount thereof to
be redeemed.  For all purposes of this Indenture, unless the context otherwise
requires, all provisions relating to the redemption of Securities shall relate,
in the case of any Security redeemed or to be redeemed only in part, to the
portion of the principal amount of such Security which has been or is to be
redeemed.  If the Company shall so direct, Securities registered in the name of
the Company, any Affiliate or any Subsidiary thereof shall not be included in
the Securities selected for redemption.

          SECTION 11.4.  Notice of Redemption.

          Notice of redemption shall be given by first-class mail, postage
prepaid, mailed not later than the thirtieth day, and not earlier than the
sixtieth day, prior to the Redemption Date, to each Holder of Securities to be
redeemed, at the address of such Holder as it appears in the Securities
Register.

          With respect to Securities of each series to be redeemed, each notice
of redemption shall identify the Securities to be redeemed (including CUSIP 
numbers) and shall state:

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<PAGE>
 
          (a)  the Redemption Date;

          (b)  the Redemption Price;

          (c)  if less than all Outstanding Securities of such particular series
and having the same terms are to be redeemed, the identification (and, in the
case of partial redemption, the respective principal amounts) of the particular
Securities to be redeemed;

          (d)  that on the Redemption Date, the Redemption Price will become due
and payable upon each such Security or portion thereof, and that interest
thereon, if any, shall cease to accrue on and after said date;

          (e)  the place or places where such Securities are to be surrendered
for payment of the Redemption Price; and

          (f)  that the redemption is for a sinking fund, if such is the case.

          Notice of redemption of Securities to be redeemed at the election of
the Company shall be given by the Company or, at the Company's request, by the
Trustee in the name and at the expense of the Company and shall be irrevocable.
The notice if mailed in the manner herein provided shall be conclusively
presumed to have been duly given, whether or not the Holder receives such
notice. In any case, a failure to give such notice by mail or any defect in the
notice to the Holder of any Security designated for redemption as a whole or in
part shall not affect the validity of the proceedings for the redemption of any
other Security.

          SECTION 11.5.  Deposit of Redemption Price.

          Prior to 11:00 a.m. New York City time on the Redemption Date
specified in the notice of redemption given as provided in Section 11.4, the
Company will deposit with the Trustee or with one or more Paying Agents (or if
the Company is acting as its own Paying Agent, the Company will segregate and
hold in trust as provided in Section 10.3) an amount of money sufficient to pay
the Redemption Price of, and any accrued interest (including Additional
Interest) on, all the Securities which are to be redeemed on that date.

          SECTION 11.6.  Payment of Securities Called for Redemption.

          If any notice of redemption has been given as provided in Section
11.4, the Securities or portion of Securities with respect to which such notice
has been given shall become due and payable on the date and at the place or
places stated in such notice at the applicable Redemption

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<PAGE>
 
Price.  On presentation and surrender of such Securities at a Place of Payment
in said notice specified, the said securities or the specified portions thereof
shall be paid and redeemed by the Company at the applicable Redemption Price,
together with accrued interest (including any Additional Interest) to the
Redemption Date; provided, however, that, unless otherwise specified as
contemplated by Section 3.1, installments of interest whose Stated Maturity is
on or prior to the Redemption Date will be payable to the Holders of such
Securities, or one or more Predecessor Securities, registered as such at the
close of business on the relevant Record Dates According to their terms and the
provisions of Section 3.7.

          Upon presentation of any Security redeemed in part only, the Company
shall execute and the Trustee shall authenticate and deliver to the Holder
thereof, at the expense of the Company, a new Security or Securities of the same
series, of authorized denominations, in aggregate principal amount equal to the
unredeemed portion of the Security so presented and having the same Original
Issue Date, Stated Maturity and terms.  If a Global Security is so surrendered,
such new Security will also be a new Global Security.

          If any Security called for redemption shall not be so paid upon
surrender thereof for redemption, the principal of and premium, if any, on such
Security shall, until paid, bear interest from the Redemption Date at the rate
prescribed therefor in the Security.


                                  ARTICLE XII

                                 SINKING FUNDS

          SECTION 12.1.  Applicability of Article.

          The provisions of this Article shall be applicable to any sinking fund
for the retirement of Securities of any series except as otherwise specified as
contemplated by Section 3.1 for such Securities.

          The minimum amount of any sinking fund payment provided for by the
terms of any Securities of any series is herein referred to as a "mandatory
sinking fund payment", and any sinking fund payment in excess of such minimum
amount which is permitted to be made by the terms of such Securities of any
series is herein referred to as an "optional sinking fund payment". If provided
for by the terms of any Securities of any series, the cash amount of any sinking
fund payment may be subject to reduction as provided in Section 12.2. Each
sinking fund payment shall be applied to the redemption of Securities of any
series as provided for by the terms of such Securities.

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<PAGE>
 
       SECTION 12.2.  Satisfaction of Sinking Fund Payments with Securities.

       In lieu of making all or any part of a mandatory sinking fund payment
with respect to any Securities of a series in cash, the Company may at its
option, at any time no more than 16 months and no less than 30 days prior to the
date on which such sinking fund payment is due, deliver to the Trustee
Securities of such series (together with the unmatured coupons, if any,
appertaining thereto) theretofore purchased or otherwise acquired by the
Company, except Securities of such series that have been redeemed through the
application of mandatory or optional sinking fund payments pursuant to the terms
of the Securities of such series, accompanied by a Company Order instructing the
Trustee to credit such obligations and stating that the Securities of such
series were originally issued by the Company by way of bona fide sale or other
negotiation for value; provided that the Securities to be so credited have not
been previously so credited.  The Securities to be so credited shall be received
and credited for such purpose by the Trustee at the redemption price for such
Securities, as specified in the Securities so to be redeemed, for redemption
through operation of the sinking fund and the amount of such sinking fund
payment shall be reduced accordingly.

       SECTION 12.3.  Redemption of Securities for Sinking Fund.

       Not less than 60 days prior to each sinking fund payment date for any
series of Securities, the Company will deliver to the Trustee an Officers'
Certificate specifying the amount of the next ensuing sinking fund payment for
such Securities pursuant to the terms of such Securities, the portion thereof,
if any, which is to be satisfied by payment of cash in the currency in which the
Securities of such series are payable (except as provided pursuant to Section
3.1) and the portion thereof, if any, which is to be satisfied by delivering and
crediting Securities pursuant to Section 12.2 and will also deliver to the
Trustee any Securities to be so delivered.  Such Officers' Certificate shall be
irrevocable and upon its delivery the Company shall be obligated to make the
cash payment or payments therein referred to, if any, on or before the
succeeding sinking fund payment date.  In the case of the failure of the Company
to deliver such Officers' Certificate (or, as required by this Indenture, the
Securities and coupons, if any, specified in such Officers' Certificate), the
sinking fund payment due on the succeeding sinking fund payment date for such
series shall be paid entirely in cash and shall be sufficient to redeem the
principal amount of the Securities of such series subject to a mandatory sinking
fund payment without the right to deliver or credit securities as provided in
Section 12.2 and without the right to make the


                                      80
<PAGE>
 
optional sinking fund payment with respect to such series at such time.

       Any sinking fund payment or payments (mandatory or optional) made in cash
plus any unused balance of any preceding sinking fund payments made with respect
to the Securities of any particular series shall be applied by the Trustee (or
by the Company if the Company is acting as its own Paying Agent) on the sinking
fund payment date on which such payment is made (or, if such payment is made
before a sinking fund payment date, on the sinking fund payment date immediately
following the date of such payment) to the redemption of Securities of such
series at the Redemption Price specified in such Securities with respect to the
sinking fund.  Any sinking fund moneys not so applied or allocated by the
Trustee (or, if the Company is acting as its own Paying Agent, segregated and
held in trust by the Company as provided in Section 10.3) for such series and
together with such payment (or such amount so segregated) shall be applied in
accordance with the provisions of this Section 12.3. Any and all sinking fund
moneys with respect to the Securities of any particular series held by the
Trustee (or if the Company is acting as its own Paying Agent, segregated and
held in trust as provided in Section 10.3) on the last sinking fund payment date
with respect to Securities of such series and not held for the payment or
redemption of particular Securities of such series shall be applied by the
Trustee (or by the Company if the Company is acting as its own Paying Agent),
together with other moneys, if necessary, to be deposited (or segregated)
sufficient for the purpose, to the payment of the principal of the Securities of
such series at Maturity.  The Trustee shall select the Securities to be redeemed
upon such sinking fund payment date in the manner specified in Section 11.3 and
cause notice of the redemption thereof to be given in the name of and at the
expense of the Company in the manner provided in Section 11.4. Such notice
having been duly given, the redemption of such Securities shall be made upon the
terms and in the manner stated in Section 11.6. On or before each sinking fund
payment date, the Company shall pay to the Trustee (or, if the Company is acting
as its own Paying Agent, the Company shall segregate and hold in trust as
provided in Section 10.3) in cash a sum in the currency in which Securities of
such series are payable (except as provided pursuant to Section 3.1) equal to
the principal and any interest accrued to the Redemption Date for Securities or
portions thereof to be redeemed on such sinking fund payment date pursuant to
this Section 12.3.

       Neither the Trustee nor the Company shall redeem any Securities of a
series with sinking fund moneys or mail any notice of redemption of Securities
of such series by operation of the sinking fund for such series during the
continuance of a default in payment of interest, if any, on any Securities of

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<PAGE>
 
such series or of any Event of Default (other than an Event of Default occurring
as a consequence of this paragraph) with respect to the Securities of such
series except that if the notice of redemption shall have been provided in
accordance with the provisions hereof, the Trustee (or the Company, if the
Company is then acting as its own Paying Agent) shall redeem such Securities if
cash sufficient for that purpose shall be deposited with the Trustee (or
segregated by the Company) for that purpose in accordance with the terms of this
Article XII.  Except as aforesaid, any moneys in the sinking fund for such
series at the time when any such default or Event of Default shall occur and any
moneys thereafter paid into such sinking fund shall, during the continuance of
such default or Event of Default, be held as security for the payment of the
Securities and coupons, if any, of such series; provided, however, that in case
such default or Event of Default shall have been cured or waived herein, such
moneys shall thereafter be applied on the next sinking fund payment date for the
Securities of such series on which such moneys may be applied pursuant to the
provisions of this Section 12.3.


                                  ARTICLE XIII

                          SUBORDINATION OF SECURITIES

       SECTION 13.1.  Securities Subordinate to Senior Debt.

       The Company covenants and agrees, and each Holder of a Security, by its
acceptance thereof, likewise covenants and agrees, that, to the extent and in
the manner hereinafter set forth in this Article, the payment of the principal
of (and premium, if any) and interest (including any Additional Interest) on
each and all of the Securities are hereby expressly made subordinate and subject
in right of payment to the prior payment in full of all Senior Debt.

       SECTION 13.2.  Payment Over of Proceeds Upon Dissolution, Etc.

       In case of the pendency of any receivership, insolvency, liquidation,
bankruptcy, reorganization, arrangement, adjustment, composition or other
similar judicial proceeding relative to the Company (each such event, if any,
herein sometimes referred to as a "Proceeding"), then the holders of Senior Debt
shall be entitled to receive payment in full of all amounts due or to become due
on such Senior Debt, or provision shall be made for such payment in cash or cash
equivalents or otherwise in a manner satisfactory to the holders of Senior Debt,
before the Holders of the Securities are entitled to receive or retain any
payment or distribution

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<PAGE>
 
of any kind or character, whether in cash, property or Securities (including any
payment or distribution which may be payable or deliverable by reason of the
payment of any other Debt of the Company (including any series of the
Securities) subordinated to the payment of the Securities, such payment or
distribution being hereinafter referred to as a "Junior Subordinated Payment"),
on account of principal of (or premium, if any) or interest (including any
Additional Interest) on the Securities or on account of the purchase or other
acquisition of Securities by the Company or any Subsidiary and to that end the
holders of Senior Debt shall be entitled to receive, for application to the
payment thereof, any payment or distribution of any kind or character, whether
in cash, property or securities, including any Junior Subordinated Payment,
which may be payable or deliverable in respect of the Securities in any such
Proceeding; provided, however, that nothing in this Section shall prevent the
satisfaction of any sinking fund payment in accordance with this Indenture or as
otherwise specified as contemplated by Section 3.1 for the Securities of any
series by delivering and crediting pursuant to Section 12.2 or as otherwise
specified as contemplated by Section 3.1 for the Securities of any series of
Securities which have been acquired (upon redemption or otherwise) prior to such
Proceeding.

       In the event that, notwithstanding the foregoing provisions of this
Section, the Trustee or the Holder of any Security shall have received any
payment or distribution of assets of the Company of any kind or character,
whether in cash, property or securities, including any Junior Subordinated
Payment or any sinking fund payment (except as described in the immediately
preceding paragraph), before all amounts due or to become due on all Senior Debt
are paid in full or payment thereof is provided for in cash or cash equivalents
or otherwise in a manner satisfactory to the holders of Senior Debt, then and in
such event such payment or distribution shall be received in trust and paid over
or delivered forthwith to the trustee in bankruptcy, receiver, liquidating
trustee, custodian, assignee, agent or other Person making payment or
distribution of assets of the Company for application to the payment of all
amounts due or to become due on all Senior Debt remaining unpaid, to the extent
necessary to pay all amounts due or to become due on all Senior Debt in full,
after giving effect to any concurrent payment or distribution to or for the
holders of Senior Debt.

       For purposes of this Article only, the words "any payment or distribution
of any kind or character, whether in cash, property or securities" shall not be
deemed to include shares of stock of the Company as reorganized or readjusted,
or securities of the Company or any other corporation provided for by a plan of
reorganization or readjustment which securities are subordinated in right of
payment to all then


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<PAGE>
 
outstanding Senior Debt to substantially the same extent as the Securities are
so subordinated as provided in this Article.  The consolidation of the Company
with, or the merger of the Company into, another Person or the liquidation or
dissolution of the Company following the sale of all or substantially all of its
properties and assets as an entirety to another Person upon the terms and
conditions set forth in Article VIII shall not be deemed a Proceeding for the
purposes of this Section if the Person formed by such consolidation or into
which the Company is merged or the Person which acquires by sale such properties
and assets as an entirety, as the case may be, shall, as a part of such
consolidation, merger, or sale comply with the conditions set forth in Article
VIII.

       SECTION 13.3.  Prior Payment to Senior Debt Upon Acceleration of
Securities.

       In the event that any Securities are declared due and payable before
their Stated Maturity, then and in such event the holders of the Senior Debt
outstanding at the time such Securities so become due and payable shall be
entitled to receive payment in full of all amounts due on or in respect of such
Senior Debt (including any amounts due upon acceleration), or provision shall be
made for such payment in cash or cash equivalents or otherwise in a manner
satisfactory to the holders of Senior Debt, before the Holders of the Securities
are entitled to receive any payment or distribution of any kind or character,
whether in cash, properties or securities (including any Junior Subordinated
Payment or, except as provided below, any sinking fund payment) by the Company
on account of the principal of (or premium, if any) or interest (including any
Additional Interest) on the Securities or on account of the purchase or other
acquisition of Securities by the Company or any Subsidiary; provided, however,
that nothing in this Section shall prevent the satisfaction of any sinking fund
payment in accordance with this Indenture or as otherwise specified as
contemplated by Section 3.1 for the Securities of any series by delivering and
crediting pursuant to Section 12.2 or as otherwise specified as contemplated by
Section 3.1 for the Securities of any series Securities which have been acquired
(upon redemption or otherwise) prior to such declaration of acceleration.

       In the event that, notwithstanding the foregoing, the Company shall make
any payment to the Trustee or the Holder of any Security prohibited by the
foregoing provisions


                                      84
<PAGE>
 
of this Section, and if such fact shall, at or prior to the time of such
payment, have been made actually known to a Responsible Officer of the Trustee
or, as the case may be, such Holder, then and in such event such payment shall
be paid over and delivered forthwith to the holders of Senior Debt or their
representatives or agents.

       The provisions of this Section shall not apply to any payment with
respect to which Section 13.2 would be applicable.

       SECTION 13.4.  No Payment When Senior Debt in Default.

       (a) In the event and during the continuation of any default in the
payment of principal of (or premium, if any) or interest on any Senior Debt, or
in the event that any event of default with respect to any Senior Debt shall
have occurred and be continuing and shall have resulted in such Senior Debt
becoming or being declared due and payable prior to the date on which it would
otherwise have become due and payable, unless and until such event of default
shall have been cured or waived or shall have ceased to exist and such
acceleration shall have been rescinded or annulled, or in the event any judicial
proceeding shall be pending with respect to any such default in payment or such
event of default, then no payment or distribution of any kind or character,
whether in cash, properties or securities (including any Junior Subordinated
Payment or any sinking fund payment, except as provided below) shall be made by
the Company on account of principal of (or premium, if any) or interest
(including any Additional Interest), if any, on the Securities or on account of
the purchase or other acquisition of Securities by the Company or any
Subsidiary, in each case unless and until all amounts due or to become due on
such Senior Debt are paid in full.

                                      85
<PAGE>
 
Nothing in this Section shall prevent the satisfaction of any sinking fund
payment in accordance with this Indenture or as otherwise specified as
contemplated by Section 3.1 for the Securities of any series by delivering and
crediting pursuant to Section 12.2 or as otherwise specified as contemplated by
Section 3.1 for the Securities of any series Securities which have been acquired
(upon redemption or otherwise) prior to such default in payment or event of
default.

       In the event that, notwithstanding the foregoing, the Company shall make
any payment to the Trustee or the Holder of any Security prohibited by the
foregoing provisions of this Section, and if such fact shall, have been made
actually known to a Responsible Officer of the Trustee or, as the case may be,
such Holder, then and in such event such payment shall be paid over and
delivered forthwith to the holders of Senior Debt or their representatives or
agents.

       The provisions of this Section shall not apply to any payment with
respect to which Section 13.2 would be applicable.

       SECTION 13.5.  Obligations of Company Unconditional.

       Nothing contained in this Article or elsewhere in this Indenture or in
any of the Securities shall prevent (a) the Company, at any time except during
the pendency of any Proceeding referred to in Section 13.2 or under the
conditions described in Sections 13.3 and 13.4, from making payments at any time
of principal of (and premium, if any) or interest (including Additional
Interest) on the Securities, or (b) the application by the Trustee of any money
deposited with it


                                      86
<PAGE>
 
hereunder to the payment of or on account of the principal of (and premium, if
any) or interest (including any Additional Interest) on the Securities or the
retention of such payment by the Holders, if, at the time of such application by
the Trustee, a Responsible Officer of the Trustee did not have actual knowledge
that such payment would have been prohibited by the provisions of this Article.
Notwithstanding the foregoing, the failure of the Company to make a payment on
account of principal of (or premium, if any) or interest on (including any
Additional Interest) the Securities by reason of any provision of this Article
XIII shall not prevent the occurrence of an Event of Default under Article V, or
prevent the Holder of any Security from exercising all remedies otherwise
permitted by applicable law upon the occurrence of an Event of Default, subject
to the rights, if any, under this Article XIII of the holders of Senior Debt in
respect of cash, property or securities of the Company received upon the
exercise of any such remedy.

       SECTION 13.6.  Subrogation to Rights of Holders of Senior Debt.

       Subject to the payment in full of all amounts due or to become due on all
Senior Debt to the extent provided herein, or the provision for such payment in
cash or cash equivalents or otherwise in a manner satisfactory to the holders of
Senior Debt, the Holders of the Securities shall be subrogated to the extent of
the payments or distributions made to the holders of such Senior Debt pursuant
to the provisions of this Article (equally and ratably with the holders of all
indebtedness of the Company which by its express terms is subordinated to Senior
Debt of the Company to substantially the same extent as the Securities are
subordinated to the Senior Debt and is entitled to like rights of subrogation by
reason of any payments or distributions made to holders of such Senior Debt) to
the rights of the holders of such Senior Debt to receive payments and
distributions of cash, property and securities applicable to the Senior Debt
until the principal of (and premium, if any) and interest (including Additional
Interest) on the Securities shall be paid in full.  For purposes of such
subrogation, no payments or distributions to the holders of the Senior Debt of
any cash, property or securities to which the Holders of the Securities or the
Trustee would be entitled except for the provisions of this Article, and no
payments over pursuant to the provisions of this Article to the holders of
Senior Debt by Holders of the Securities or the Trustee, shall, as among the
Company, its creditors other than holders of Senior Debt, and the Holders of the
Securities, be deemed to be a payment or distribution by the Company to or on
account of the Senior Debt.  A release of any claim by any holder of Senior Debt
shall not limit the Rights of the Holders of Securities under this Section 13.6.


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<PAGE>
 
       SECTION 13.7.  Provisions Solely to Define Relative Rights.

       The provisions of this Article are and are intended solely for the
purpose of defining the relative rights of the Holders of the Securities on the
one hand and the holders of Senior Debt on the other hand.  Nothing contained in
this Article or elsewhere in this Indenture or in the Securities is intended to
or shall (a) impair, as between the Company and the Holders of the Securities,
the obligations of the Company, which are absolute and unconditional, to pay to
the Holders of the Securities the principal of (and premium, if any) and
interest (including any Additional Interest) on the Securities as and when the
same shall become due and payable in accordance with their terms; or (b) affect
the relative rights against the Company of the Holders of the Securities and
creditors of the Company other than their rights in relation to the holders of
Senior Debt; or (c) prevent the Trustee or the Holder of any Security from
exercising all remedies otherwise permitted by applicable law upon default under
this Indenture including, without limitation, filing and voting claims in any
Proceeding, subject to the rights, if any, under this Article of the holders of
Senior Debt to receive cash, property and securities otherwise payable or
deliverable to the Trustee or such Holder.

       SECTION 13.8.    Trustee to Effectuate Subordination.

       Each Holder of a Security by his or her acceptance thereof authorizes and
directs the Trustee on his or her behalf to take such action as may be necessary
or appropriate to acknowledge or effectuate the subordination provided in this
Article and appoints the Trustee his or her attorney-in-fact for any and all
such purposes.

       SECTION 13.9.  No Waiver of Subordination Provisions.

       No right of any present or future holder of any Senior Debt to enforce
subordination as herein provided shall at any time in any way be prejudiced or
impaired by any act or failure to act on the part of the Company or by any act
or failure to act, in good faith, by any such holder, or by any noncompliance by
the Company with the terms, provisions and covenants of this Indenture,
regardless of any knowledge thereof that any such holder may have or be
otherwise charged with.

       Without in any way limiting the generality of the immediately preceding
paragraph, the holders of Senior Debt may, at any time and from to time, without
the consent of or notice to the Trustee or the Holders of the Securities,
without incurring responsibility to the Holders of the


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Securities and without impairing or releasing the subordination provided in this
Article or the obligations hereunder of the Holders of the Securities to the
holders of Senior Debt, do any one or more of the following: (i) change the
manner, place or terms of payment or extend the time of payment of, or renew or
alter, Senior Debt, or otherwise amend or supplement in any manner Senior Debt
or any instrument evidencing the same or any agreement under which Senior Debt
is outstanding; (ii) sell, exchange, release or otherwise deal with any property
pledged, mortgaged or otherwise securing Senior Debt; (iii) release any Person
liable in any manner for the collection of Senior Debt; and (iv) exercise or
refrain from exercising any rights against the Company and any other Person.

       SECTION 13.10. Notice to Trustee.

       The Company shall give prompt written notice to the Trustee of any fact
known to the Company which would prohibit the making of any payment to or by the
Trustee in respect of the Securities.  Notwithstanding the provisions of this
Article or any other provision of this Indenture, the Trustee shall not be
charged with knowledge of the existence of any facts which would prohibit the
making of any payment to or by the Trustee in respect of the Securities, unless
and until the Trustee shall have received written notice thereof from the
Company or a holder of Senior Debt or from any trustee, agent or representative
therefor; provided, however, that if the Trustee shall not have received the
notice provided for in this Section at least two Business Days prior to the date
upon which by the terms hereof any monies may become payable for any purpose
(including, without limitation, the payment of the principal of (and premium, if
any) or interest (including any Additional Interest) on any Security), then,
anything herein contained to the contrary notwithstanding, the Trustee shall be
entitled to assume conclusively that such facts do not exist and the Trustee
shall have full power and authority to receive such monies and to apply the same
to the purpose for which they were received and shall not be affected by any
notice to the contrary which may be received by it within two Business Days
prior to such date.

       Subject to the provisions of Section 6.1, the Trustee shall be entitled
to conclusively rely on the delivery to it of a written notice by a Person
representing himself to be a holder of Senior Debt (or a trustee therefor) to
establish that such notice has been given by a holder of Senior Debt (or a
trustee therefor).  In the event that the Trustee determines in good faith that
further evidence is required with respect to the right of any Person as a holder
of Senior Debt to participate in any payment or distribution pursuant to this
Article, the Trustee may request such Person to furnish evidence to the
reasonable satisfaction of the

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Trustee as to the amount of Senior Debt held by such Person, the extent to which
such Person is entitled to participate in such payment or distribution and any
other facts pertinent to the rights of such Person under this Article, and if
such evidence is not furnished, the Trustee may defer any payment to such Person
pending judicial determination as to the right of such Person to receive such
payment.

       SECTION 13.11. Reliance on Judicial Order or Certificate of Liquidating
Agent.

       Upon any payment or distribution of assets of the Company referred to in
this Article, the Trustee, subject to the provisions of Section 6.1, and the
Holders of the Securities shall be entitled to conclusively rely upon any order
or decree entered by any court of competent jurisdiction in which such
Proceeding is pending, or a certificate of the trustee in bankruptcy, receiver,
liquidating trustee, custodian, assignee for the benefit of creditors, agent of
the foregoing or other Person making such payment or distribution, delivered to
the Trustee or to the Holders of Securities, for the purpose of ascertaining the
Persons entitled to participate in such payment or distribution, the holders of
the Senior Debt and other indebtedness of the Company, the amount thereof or
payable thereon, the amount or amounts paid or distributed thereon and all other
facts pertinent thereto or to this Article.

       SECTION 13.12. Trustee Not Fiduciary for Holders of Senior Debt.

       The Trustee, in its capacity as trustee under this Indenture, shall not
be deemed to owe any fiduciary duty to the holders of Senior Debt and shall not
be liable to any such holders if it shall in good faith mistakenly pay over or
distribute to Holders of Securities or to the Company or to any other Person
cash, property or securities to which any holders of Senior Debt shall be
entitled by virtue of this Article or otherwise.

       SECTION 13.13. Rights of Trustee as Holder of Senior Debt; Preservation
of Trustee's Rights.

       The Trustee in its individual capacity shall be entitled to all the
rights set forth in this Article with respect to any Senior Debt which may at
any time be held by it, to the same extent as any other holder of Senior Debt,
and nothing in this Indenture shall deprive the Trustee of any of its rights as
such holder.  Nothing in this Article shall apply to claims of, or payments to,
the Trustee under or pursuant to Section 6.7.


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       SECTION 13.14.  Article Applicable to Paying Agents.

       In case at any time any Paying Agent other than the Trustee shall have
been appointed by the Company and be then acting hereunder, the term "Trustee"
as used in this Article shall in such case (unless the context otherwise
requires) be construed as extending to and including such Paying Agent within
its meaning as fully for all intents and purposes as if such Paying Agent were
named in this Article in addition to or in place of the Trustee.

       SECTION 13.15. Certain Conversions or Exchanges Deemed Payment.

       For the purposes of this Article only, (a) the issuance and delivery of
junior securities upon conversion or exchange of Securities shall not be deemed
to constitute a payment or distribution on account of the principal of (or
premium, if any) or interest (including any Additional Interest) on Securities
or on account of the purchase or other acquisition of Securities, and (b) the
payment, issuance or delivery of cash, property or securities (other than junior
securities) upon conversion or exchange of a Security shall be deemed to
constitute payment on account of the principal of such security.  For the
purposes of this Section, the term "junior securities" means (i) shares of any
stock of any class of the Company and (ii) securities of the Company which are
subordinated in right of payment to all Senior Debt which may be outstanding at
the time of issuance or delivery of such securities to substantially the same
extent as, or to a greater extent than, the Securities are so subordinated as
provided in this Article.

                                    * * * *

       This instrument may be executed in any number of counterparts, each of
which so executed  shall be deemed to be an original, but all such counterparts
shall together constitute but one and the same instrument.


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       IN WITNESS WHEREOF, the parties hereto have caused this Indenture to be
duly executed, all as of the day and year first above written.


                                   Houston Lighting & Power Company



                                   By
                                     ------------------------------
                                   Name:
                                        ---------------------------
                                   Title: Vice President


                                   The Bank of New York,
                                   as trustee



                                   By:
                                      -----------------------------
                                        Name:
                                        Title:




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