Document:

Exhibit 4-b

                      FIXED RATE GLOBAL MEDIUM-TERM NOTE

[If this Note is an OID Note (as defined below) the following legend is
applicable:

FOR PURPOSES OF SECTIONS 1272, 1273 AND 1275 OF THE UNITED STATES INTERNAL
REVENUE CODE OF 1986, AS AMENDED, THE ISSUE PRICE OF THIS NOTE IS _____, THE
AMOUNT OF ORIGINAL ISSUE DISCOUNT IS __________, THE YIELD TO MATURITY IS
_______ AND THE ISSUE DATE IS ___________.]
 .
THIS NOTE 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 THEREOF.  UNLESS AND UNTIL IT IS EXCHANGED IN WHOLE OR IN PART FOR
NOTES IN CERTIFICATED FORM, THIS NOTE MAY NOT BE TRANSFERRED EXCEPT AS A
WHOLE BY THE DEPOSITORY TRUST COMPANY (THE "DEPOSITARY") TO A NOMINEE OF THE
DEPOSITARY OR BY THE DEPOSITARY OR ANY SUCH NOMINEE TO A SUCCESSOR DEPOSITARY
OR A NOMINEE OF SUCH SUCCESSOR DEPOSITARY.  UNLESS THIS NOTE IS PRESENTED BY
AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITARY TO THE COMPANY OR ITS AGENT
FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY NOTE ISSUED IS
REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS REQUESTED BY AN
AUTHORIZED REPRESENTATIVE OF THE DEPOSITARY (AND ANY PAYMENT IS MADE TO CEDE
& CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE
OF THE DEPOSITARY), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR
OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER
HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

REGISTERED                                                   PRINCIPAL AMOUNT
No. FX ___________           CUSIP No. ___________           $_______________

<PAGE>

                             KEYSPAN GAS EAST CORPORATION
                                    MEDIUM-TERM NOTE,
                                       SERIES A
                                     (Fixed Rate)

ORIGINAL ISSUE DATE:               INTEREST RATE:             STATED MATURITY:

INTEREST PAYMENT DATES:           REGULAR RECORD DATE:

                                                                   ANNUAL
                                                                   REDEMPTION
INITIAL REDEMPTION DATE:                      INITIAL REDEMPTION   PERCENTAGE
                                    PERCENTAGE:                    REDUCTION:

OPTIONAL
REPAYMENT DATE(S):

DENOMINATIONS:                                                     ADDENDUM
(Integral multiples of                                             ATTACHED:
$1,000,
unless otherwise specified)                                        : Yes
                                                                   : No

OTHER PROVISIONS:

                                      -2-

<PAGE>

          KEYSPAN GAS EAST CORPORATION, a Delaware corporation (the "Issuer"
or the "Company," which terms include any successor corporation under the
Indenture hereinafter referred to), for value received, hereby promises to
pay to CEDE & CO., or registered assigns, the principal sum of
                                              DOLLARS on the Stated Maturity
specified above (except to the extent redeemed or repaid prior to the Stated
Maturity), and to pay interest thereon at the Interest Rate per annum
specified above, until the principal hereof is paid or duly made available
for payment.  Reference herein to "this Note", "hereof", "herein" and
comparable terms shall include an Addendum hereto if an Addendum is specified
above.

          The Company will pay interest on each Interest Payment Date
specified above, commencing on the first Interest Payment Date next
succeeding the Original Issue Date specified above, and on the Stated
Maturity or any Redemption Date or Optional Repayment Date (as defined below)
(the date of each such Stated Maturity, Redemption Date and Optional
Repayment Date and the date on which principal or an installment of principal
is due and payable by declaration of acceleration pursuant to the Indenture
being referred to hereinafter as a "Maturity" with respect to principal
payable on such date); provided, however, that if the Original Issue Date is
between a Regular Record Date (as defined below) and the next succeeding
Interest Payment Date, interest payments will commence on the second Interest
Payment Date succeeding the Original Issue Date.  Unless otherwise specified
above, the "Regular Record Date" shall be the date 15 calendar days (whether
or not a Business Day) prior to the applicable Interest Payment Date.
Interest on this Note will accrue from and including the most recent Interest
Payment Date to which interest has been paid or duly provided for or, if no
interest has been paid, from the Original Issue Date specified above, to, but
excluding such Interest Payment Date.  If the Maturity or an Interest Payment
Date falls on a day which is not a Business Day, the payment due on such
Maturity or Interest Payment Date will be paid on the next succeeding
Business Day with the same force and effect as if made on such Maturity or
Interest Payment Date, as the case may be, and no interest shall accrue with
respect to such payment for the period from and after such Maturity or
Interest Payment Date.  The interest 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 Note (or one or more Predecessor
Securities) is registered at the close of business on the Regular Record Date
for such Interest Payment Date.  Any such interest which is payable, but not
punctually paid or duly provided for on any Interest Payment Date (herein
called "Defaulted Interest"), shall forthwith cease to be payable to the
registered Holder on such Regular Record Date, and may be paid to the Person
in whose name this Note (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 the Holder of this Note not less than 10 days prior to such Special Record

                                      -3-

<PAGE>

Date, or may be paid at any time in any other lawful manner, all as more
fully provided in the Indenture.

          The Notes are, and all other Securities issued under the Indenture
will be, unconditionally guaranteed as to payment of principal (and premium,
if any), interest, if any, and additional amounts, if any, by KeySpan
Corporation, a Delaware corporation (the "Guarantor").

          Payment of the principal of (and premium, if any) and interest on
this Note will be made at the office or agency of the Company maintained by
the Company for such purpose in the Borough of Manhattan, The City of New
York, 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.

          Unless the certificate of authentication hereon has been executed
by or on behalf of The Chase Manhattan Bank, the Trustee for this Note under
the Indenture, or its successor thereunder, by the manual signature of one of
its authorized officers, this Note shall not be entitled to any benefit under
the Indenture or be valid or obligatory for any purpose.

          This Note is one of a duly authorized issue of Securities
(hereinafter called the "Securities") of the Company designated as its
Medium-Term Notes, Series A (the "Notes").  The Securities are issued and to
be issued under an indenture (the "Indenture") dated as of December 1, 1999,
between the Company, the Guarantor and The Chase Manhattan Bank (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 thereunder
of the Company, the Guarantor, the Trustee and the Holders of the Notes and
the terms upon which the Notes are to be authenticated and delivered.  The
terms of other Notes may vary with respect to interest rates or interest rate
formulas, issue dates, maturity, redemption, repayment, currency of payment
and otherwise as provided in the Indenture.

          The Notes are issuable only in registered form without coupons in
denominations, unless otherwise specified above, of $1,000 and integral
multiples thereof.  As provided in the Indenture and subject to certain
limitations therein set forth, the Notes are exchangeable for a like
aggregate principal amount of Notes as requested by the Holder surrendering
the same.  If (x) the Depositary is at any time unwilling or unable to
continue as depository and a successor depository is not appointed by the
Company within 90 days, (y) the Company delivers to the Trustee a Company
Order to the effect that this Note shall be exchangeable or (z) an Event of
Default has occurred and is continuing with respect to the Notes, this Note
shall be exchangeable for Notes in definitive form of like tenor and in an
equal aggregate principal amount, in authorized denominations.  Such
definitive Notes shall be registered in such name or names as the Depositary

                                      -4-

<PAGE>

shall instruct the Trustee.  If definitive Notes are so delivered, the
Company may make such changes to the form of this Note as are necessary or
appropriate to allow for the issuance of such definitive Notes.

          This Note is not subject to any sinking fund.

          This Note may be subject to repayment at the option of the Holder
prior to its Stated Maturity on any Holder's Optional Repayment Date(s), if
any, indicated above.  If no Optional Repayment Dates are set forth above,
this Note may not be so repaid at the option of the Holder hereof prior to
the Stated Maturity.  On any Optional Repayment Date this Note shall be
repayable in whole or in part in an amount equal to $1,000 or any integral
multiple thereof (provided that any remaining principal amount shall be an
authorized denomination) at the option of the Holder hereof at a repayment
price equal to 100% of the principal amount to be repaid, together with
interest thereon payable to the date of repayment.  For this Note to be
repaid in whole or in part at the option of the Holder hereof, this Note must
be received, with the form entitled "Option to Elect Repayment" below duly
completed, by the Trustee at its office at 450 West 33rd Street, 15th Floor,
New York, New York 10001 or such address which the Company shall from time to
time notify the Holder hereof ("Corporate Trust Office"), not more than 60
nor less than 30 days prior to an Optional Repayment Date.  This Note must be
received by the Trustee by 5:00 P.M., New York City time, on the last day for
giving such notice.  Exercise of such repayment option by the Holder hereof
shall be irrevocable.  In the event of payment of this Note in part only, a
new Note for the unpaid portion hereof shall be issued in the name of the
Holder hereof upon the surrender hereof.

          This Note may be redeemed at the option of the Company prior to its
Stated Maturity on any date on and after the Initial Redemption Date, if any,
specified above (the "Redemption Date").  If no Initial Redemption Date is
set forth above, this Note may not be redeemed at the option of the Company
prior to the Stated Maturity.  On and after the Initial Redemption Date, if
any, this Note may be redeemed at any time in whole or from time to time in
part in increments of $1,000 (provided that any remaining principal amount
shall be an authorized denomination) at the option of the Company at the
applicable Redemption Price (as defined below) together with interest thereon
payable to the Redemption Date, on notice given not more than 60 nor less
than 30 days prior to the Redemption Date.  In the event of redemption of
this Note in part only, a new Note for the unredeemed portion hereof shall be
issued in the name of the Holder hereof upon the surrender hereof.

          If this Note is redeemable at the option of the Company prior to
its Stated Maturity, the "Redemption Price" shall initially be the Initial
Redemption Percentage, specified above, of the principal amount of this Note
to be redeemed and shall decline at each anniversary of the Initial
Redemption Date by the Annual Redemption Percentage Reduction, if any,

                                      -5-

<PAGE>

specified above, of the principal amount to be redeemed until the Redemption
Price is 100% of such principal amount.

          Interest on this Note will accrue from, and including, the Original
Issue Date indicated above, or the most recent date to which interest has
been paid or duly provided for, to, but excluding, the related Interest
Payment Date or Maturity, as the case may be, at the Interest Rate per annum
stated above until the principal amount hereof is paid or made available for
payment.  Unless otherwise specified above, interest will be computed on the
basis of a 360-day year of twelve 30-day months for the period specified
hereunder.

          Any provision contained herein with respect to the calculation of
the interest applicable to this Note, its payment dates or any other matter
relating hereto may be modified as specified in an Addendum relating hereto
if so specified above or as set forth under "Other Provisions" if so set
forth above.

          If an Event of Default (as defined in the Indenture) with respect
to the Notes shall occur and be continuing, the principal of all the Notes
may be declared due and payable in the manner and with the effect provided in
the Indenture.  If the principal of any Original Issue Discount Note is
declared to be due and payable immediately, the amount of principal due and
payable with respect to such Note shall be limited to the amount equal to (i)
the sum of the aggregate principal amount of such Note multiplied by the
price (expressed as a percentage of the aggregate principal amount) at which
such Note will be issued (the "Issue Price") plus (ii) the original issue
discount accrued from the date of issue to the date of declaration, which
accrual shall be calculated using the "interest method" computed in
accordance with generally accepted accounting principals in effect on the
date of declaration.  An "Original Issue Discount Note" means (i) a Note,
including any zero-coupon Note, that has a stated redemption price at
maturity that exceeds the initial offering price to the public at which a
substantial amount of an offering is sold by at least 0.25% of its principal
amount multiplied by the number of full years from the Original Issue Date to
the stated Maturity for such Note and which is designated as an Original
Issue Discount Note in the terms of such Note pursuant to the Indenture, and
(ii) any other Note designated by the Company as issued with original issue
discount for United States federal income tax purposes.

          The Indenture permits, with certain exceptions as therein provided,
the amendment or modification thereof at any time by the Company, the
Guarantor and the Trustee with the consent of the Holders of more than 50% in
principal amount of the Securities at the time outstanding of each series
issued under the Indenture to be affected thereby.  The Indenture also
contains provisions permitting the Holders of more than 50% in principal
amount of the Securities of each series at the time outstanding, on behalf of

                                      -6-

<PAGE>

the Holders of all the Securities of that series, to waive compliance by the
Company and the Guarantor with certain provisions of the Indenture and
certain past defaults under the Indenture and their consequences with respect
to such series.  Any such consent or waiver by the Holder of this Note shall
be conclusive and binding upon such Holder and upon all future Holders of
this Note and of any Note 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 Note.

          No reference herein to the Indenture and no provision of this Note
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 Note at the time, place and rate, and in the coin
or currency, herein and in the Indenture prescribed.

          As provided in the Indenture and subject to certain limitations set
forth therein and above, the transfer of this Note may be registered on the
Security Register of the Company, upon surrender of this Note for
registration of transfer at the office or agency of the Company in the
Borough of Manhattan, The City of New York, duly endorsed by, or accompanied
by a written instrument of transfer in form satisfactory to the Company duly
executed by, the Holder hereof or by his attorney duly authorized in writing,
and thereupon one or more new Notes of authorized denominations and for the
same aggregate principal amount, and having endorsed thereon a Guarantee duly
executed by the Guarantor, 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 Note for registration of transfer,
the Company, the Guarantor, the Trustee and any agent of the Company or the
Trustee may treat the Person in whose name this Note is registered as the
owner hereof for all purposes, whether or not this Note be overdue, and
neither the Company, the Guarantor, the Trustee nor any such agent shall be
affected by notice to the contrary.

          Certain of the Company's and the Guarantor's obligations under the
Indenture with respect to Notes, may be terminated if the Company or the
Guarantor irrevocably deposits with the Trustee money or Government
Obligations sufficient to pay and discharge the entire indebtedness on all
Notes, as provided in the Indenture.

          The Indenture and the Notes shall be governed by and construed in
accordance with the laws of the State of New York.

                                      -7-

<PAGE>

          All terms used in this Note which are defined in the Indenture
shall have the meanings assigned to them in the Indenture.

          IN WITNESS WHEREOF, the Company has caused this instrument to be
duly executed, manually or in facsimile, and an imprint or facsimile of its
corporate seal to be imprinted hereon.

Dated: ____________

                                    KEYSPAN GAS EAST CORPORATION

                                    By:  ______________________________
                                         [Name and Title]

[FACSIMILE OF SEAL]

                                    Attest:

                                    By:  ______________________________
                                         [Name and Title]

CERTIFICATE OF AUTHENTICATION
This is one of the Securities of the
series designated therein referred to in
the within-mentioned Indenture.

THE CHASE MANHATTAN BANK,
    as Trustee

By:  ______________________________
     Authorized Officer

                                      -8-

<PAGE>

                           OPTION TO ELECT REPAYMENT

     The undersigned hereby irrevocably request(s) and instruct(s) the
Company to repay this Note (or portion hereof specified below) pursuant to
its terms at a price equal to the principal amount hereof together with
interest to the repayment date, to the undersigned, at

        (Please print or typewrite name and address of the undersigned)

          For this Note to be repaid, the Trustee must receive at its
Corporate Trust Office, or at such other place or places of which the Company
shall from time to time notify the Holder of this Note, not more than 60 nor
less than 30 days prior to an Optional Repayment Date, if any, shown on the
face of this Note, this Note with this "Option to Elect Repayment" form duly
completed.  This Note notice must be received by the Trustee by 5:00 P.M.,
New York City time, on the last day for giving such notice.

          If less than the entire principal amount of this Note is to be
repaid, specify the portion hereof (which shall be in an amount equal to
$1,000 or an integral multiple thereof, provided that any remaining principal
amount is equal to an authorized denomination) which the Holder elects to
have repaid and specify the denomination or denominations (which shall be in
an amount equal to an authorized denomination) of the Notes to be issued to
the Holder for the portion of this Note not being repaid (in the absence of
any such specification, one such Note will be issued for the portion not
being repaid).

$ _______________________      ______________________________________________
                               NOTICE: The signature on this Option to Elect
Date_____________________      Repayment must correspond with the name as
                               written upon the face of this Note in every
                               particular, without alteration or enlargement
                               or any change whatever

                                     -9-

<PAGE>

                           ASSIGNMENT/TRANSFER FORM

          FOR VALUE RECEIVED the undersigned registered Holder hereby
sell(s), assign(s) and transfer(s) unto (insert Taxpayer Identification No.)
_____________________________________________________________________________

_____________________________________________________________________________
(Please print or typewrite name and address including postal zip code of
assignee)
_____________________________________________________________________________
the within Note and all rights thereunder, hereby irrevocably constituting
and appointing ________________________________________ attorney to transfer
said Note on the books of the Company with full power of substitution in the
premises.

Date: ____________________     ______________________________________________
                               NOTICE: The signature of the registered Holder
                               to this assignment must correspond with the
                               name as written upon the face of the within
                               instrument in every particular, without
                               alteration or enlargement or any change
                               whatsoever.

                                     -10-

<PAGE>

                                   GUARANTEE

          FOR VALUE RECEIVED, KEYSPAN CORPORATION, a New York corporation
(the "Guarantor"), hereby fully and unconditionally guarantees to each Holder
of a Note authenticated and delivered by the Trustee, and to the Trustee on
behalf of each such Holder, the due and punctual payment of the principal of
(and premium, if any) and interest, if any, on each such Note, the due and
punctual payment of any sinking fund payments provided for pursuant to the
terms of such Note and the payment of any additional amounts when and as the
same shall become due and payable, whether at the Stated Maturity, by
declaration of acceleration, call for redemption or otherwise, in accordance
with the terms of such Note and of the Indenture, dated as of December 1,
1999 (the "Indenture") by and among KeySpan Gas East Corporation (the
"Issuer" or the "Company"), the Guarantor and The Chase Manhattan Bank, as
Trustee (the "Trustee").  In case of the failure of the Company punctually to
make any such payment of principal (or premium, if any) or interest, if any,
or sinking fund payment or payment of additional amounts, the Guarantor
hereby agrees to cause any such payment to be made punctually when and as the
same shall become due and payable, whether at the Stated Maturity or by
declaration of acceleration, call for redemption or otherwise, and as if such
payment were made by the Company.

          The Guarantor hereby agrees that its obligations hereunder shall be
unconditional, irrespective of the validity, regularity or enforceability of
such Note or the Indenture, the absence of any action to enforce the same,
any waiver or consent by the Holder of such Note or by the Trustee with
respect to any provisions thereof or of the Indenture, the obtaining of any
judgment against the Company or any action to enforce the same or any other
circumstances which might otherwise constitute a legal or equitable discharge
or defense of a guarantor.  The Guarantor hereby waives the benefits of
diligence, presentment, demand of payment, filing of claims with a court in
the event of insolvency or bankruptcy of the Company, any right to require a
proceeding first against the Company, protest or notice with respect to such
Note or the indebtedness evidenced thereby or with respect to any sinking
fund payment required pursuant to the terms of such Note and all demands
whatsoever, and covenants that this Guarantee will not be discharged except
by complete performance of the obligations contained in the Notes and in this
Guarantee.  This Guarantee is a guarantee of payment and not collection.  If
the Trustee or the Holder of any Note is required by any court or otherwise
to return to the Company or the Guarantor, or any custodian, receiver,
liquidator, trustee, sequestrator or other similar official acting in
relation to the Company or the Guarantor, any amount paid to the Trustee or
such Holder in respect of a Note, this Guarantee, to the extent theretofore
discharged, shall be reinstated in full force and effect.  The Guarantor
further agrees, to the fullest extent that it lawfully may do so, that, as
between the Guarantor on the one hand, and the Holders and the Trustee, on
the other hand, the maturity of the obligations guaranteed hereby may be

                                     -11-

<PAGE>

accelerated as provided in Article V of the Indenture for the purposes of
this Guarantee, notwithstanding any stay, injunction or other prohibition
extant under any applicable bankruptcy law preventing such acceleration in
respect of the obligations guaranteed hereby.

          The Guarantor shall be subrogated to all rights of the Holders of
the Notes of a particular series against the Company in respect of any amount
paid by the Guarantor on account of such Note pursuant to the provisions of
this Guarantee or the Indenture; provided, however, that the Guarantor shall
not be entitled to enforce or to receive any payments arising out of, or
based upon, such right of subrogation until the principal of (and premium, if
any) and interest, if any, on all Notes of such series issued hereunder shall
have been paid in full.

          The Guarantor hereby certifies and warrants that all acts,
conditions and things required to be done and performed and to have happened
prior to the creation and issuance of this Guarantee and to constitute the
same as the legal, valid and binding obligation of the Guarantor enforceable
in accordance with its terms, have been done and performed and have happened
in due and strict compliance with applicable laws.

          The delivery of any Note by the Trustee, after the authentication
thereof, shall constitute due delivery of this Guarantee endorsed thereon on
behalf of the Guarantor.  The Guarantor hereby agrees that this Guarantee
shall remain in full force and effect notwithstanding any failure to endorse
on each Note a notation of this Guarantee.

          This Guarantee shall be governed by and construed in accordance
with the laws of the State of New York.

          All terms used in this Guarantee which are defined in the Indenture
shall have the meanings assigned to them in the Indenture.

          IN WITNESS WHEREOF, KEYSPAN CORPORATION has caused this Guarantee
to be duly executed in its corporate name by the facsimile signature of one
of its officers thereunto duly authorized and has caused a facsimile of its
corporate seal to be affixed hereunto or imprinted or otherwise reproduced
hereon.

Dated as of:             , 2000

                               KEYSPAN CORPORATION

                               By:  ___________________________________
                                    [Name and Title]

     [FACSIMILE OF SEAL]

                                     -12-Exhibit 4-b

                     FLOATING RATE GLOBAL MEDIUM-TERM NOTE

[If this Note is an OID Note (as defined below) the following legend is
applicable:

FOR PURPOSES OF SECTIONS 1272, 1273 AND 1275 OF THE UNITED STATES INTERNAL
REVENUE CODE OF 1986, AS AMENDED, THE ISSUE PRICE OF THIS NOTE IS _____, THE
AMOUNT OF ORIGINAL ISSUE DISCOUNT IS _________________,  THE YIELD TO
MATURITY IS _______ AND THE ISSUE DATE IS _____________________.]

THIS NOTE 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 THEREOF.  UNLESS AND UNTIL IT IS EXCHANGED IN WHOLE OR IN PART FOR
NOTES IN CERTIFICATED FORM, THIS NOTE MAY NOT BE TRANSFERRED EXCEPT AS A
WHOLE BY THE DEPOSITORY TRUST COMPANY (THE "DEPOSITARY") TO A NOMINEE OF THE
DEPOSITARY OR BY THE DEPOSITARY OR ANY SUCH NOMINEE TO A SUCCESSOR DEPOSITARY
OR A NOMINEE OF SUCH SUCCESSOR DEPOSITARY.  UNLESS THIS NOTE IS PRESENTED BY
AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITARY TO THE COMPANY OR ITS AGENT
FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY NOTE ISSUED IS
REGISTERED IN THE NAME OF CEDE & CO.  OR IN SUCH OTHER NAME AS REQUESTED BY
AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITARY (AND ANY PAYMENT IS MADE TO
CEDE & CO.  OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITARY), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF
FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE
REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

REGISTERED                      CUSIP No.               PRINCIPAL AMOUNT
No.  BFLR______________         ________________        $_______________

<PAGE>

                         KEYSPAN GAS EAST CORPORATION
                              MEDIUM-TERM NOTE,
                                   SERIES A
                               (Floating Rate)

INTEREST RATE BASIS:            ORIGINAL ISSUE DATE:         STATED MATURITY:

INDEX MATURITY:                 INITIAL INTEREST RATE:       SPREAD:

INITIAL INTEREST RESET DATE:    REGULAR RECORD DATE:         INTEREST PAYMENT
                                                             DATES:

SPREAD MULTIPLIER:                                           INTEREST RESET
                                                             DATES:

MAXIMUM INTEREST RATE:          MINIMUM INTEREST RATE:       INITIAL
                                                             REDEMPTION DATE:

INITIAL REDEMPTION              ANNUAL REDEMPTION            OPTIONAL
PERCENTAGE:                     PERCENTAGE REDUCTION:        REPAYMENT
                                                             DATE(S):

                                      -2-

<PAGE>

CALCULATION AGENTS:                                          IF INTEREST RATE
Merrill Lynch, Pierce, Fenner                                BASIS IS LIBOR:
& Smith Incorporated and J.P.
Morgan Securities Inc.
                                                             INDEX CURRENCY:

                                                             DESIGNATED LIBOR
                                                             PAGE:
                                                             [ ]Reuters Page:
                                                             _____
                                                             [ ]Telerate Page:
                                                             _____

INTEREST CALCULATION:                                        DAY COUNT
[ ]Regular Floating Rate Note                                CONVENTION:
[ ]Floating Rate/Fixed Rate                                  [ ]Actual/360 for
    Fixed Rate:                                              the period from
    Commencement Date:                                              to      .
    Fixed Interest Rate:
[ ]Inverse Floating Rate Note                                [ ]Actual/Actual
     Fixed Interest Rate:                                    to the period
                                                             from      to    .

ADDENDUM ATTACHED:                                           DENOMINATIONS:
[ ]Yes                                                       (Integral
                                                             multiples of
[ ]No                                                        $1,000, unless
                                                             otherwise
                                                             specified)

IF INTEREST RATE BASIS                                       OTHER PROVISIONS:
IS PRIME RATE:
[ ]Prime Rate--Major Ban
[ ]Prime Rate--H.15

IF INTEREST RATE BASIS  IS
CMT RATE:
[ ]Designated CMT Telerate
    Page is 7051
[ ]Designated CMT Telerate
    Page is 7052
[ ]Weekly Average
[ ]Monthly Average
    Designated CMT Maturity
    Index:

                                      -4-

<PAGE>

          KEYSPAN GAS EAST CORPORATION, a Delaware corporation ("Issuer" or
the "Company," which terms include any successor corporation under the
Indenture hereinafter referred to), for value received, hereby promises to
pay to CEDE & CO., or registered assigns, the principal sum of _____________
DOLLARS on the Stated Maturity specified above (except to the extent
redeemed or repaid prior to the Stated Maturity Date), and to pay interest
thereon, at a rate per annum equal to the Initial Interest Rate specified
above until the Initial Interest Reset Date specified above and thereafter at
a rate per annum determined in accordance with the provisions hereof and any
Addendum relating hereto depending upon the Interest Rate Basis or Bases, and
such other terms specified above, until the principal hereof is paid or duly
made available for payment.  Reference herein to "this Note", "hereof",
"herein" and comparable terms shall include an Addendum hereto if an Addendum
is specified above.

          The Company will pay interest on each Interest Payment Date
specified above, commencing on the first Interest Payment Date specified
above next succeeding the Original Issue Date specified above, and on the
Stated Maturity or any Redemption Date or Optional Repayment Date (as defined
below) (the date of each such Stated Maturity, Redemption Date and Optional
Repayment Date and the date on which principal or an installment of principal
is due and payable by declaration of acceleration pursuant to the Indenture
being referred to hereinafter as a "Maturity" with respect to principal
payable on such date); provided, however, that if the Original Issue Date is
between a Regular Record Date (as defined below) and the next succeeding
Interest Payment Date, interest payments will commence on the second Interest
Payment Date succeeding the Original Issue Date; and provided, further, that
if an Interest Payment Date (other than an Interest Payment Date at Maturity)
would fall on a day that is not a Business Day (as defined below), such
Interest Payment Date shall be postponed to the following day that is a
Business Day, except that in the case the Interest Rate Basis is LIBOR, as
indicated above, if such next Business Day falls in the next calendar month,
such Interest Payment Date shall be the next preceding day that is a Business
Day.  Except as provided above, interest payments will be made on the
Interest Payment Dates shown above.  Unless otherwise specified above, the
"Regular Record Date" shall be the date 15 calendar days (whether or not a
Business Day) prior to the applicable Interest Payment Date.  Interest on
this Note will accrue from, and including the Original Issue Date specified
above, or the most recent date to which interest has been paid or duly
provided for, to, but excluding, the related Interest Payment Date or
Maturity, as the case may be, at the rates per annum determined from time to
time as specified herein, until the principal hereof has been paid or made
available for payment.  If the Maturity falls on a day which is not a
Business Day as defined below, the payment due on such Maturity will be paid
on the next succeeding Business Day with the same force and effect as if made

                                      -5-

<PAGE>

on such Maturity and no interest shall accrue with respect to such payment
for the period from and after such Maturity.  The interest 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 Note (or
one or more Predecessor Securities) is registered at the close of business on
the Regular Record Date for such Interest Payment Date.  Any such interest
which is payable, but not punctually paid or duly provided for on any
Interest Payment Date (herein called "Defaulted Interest"), shall forthwith
cease to be payable to the registered Holder on such Regular Record Date, and
may be paid to the Person in whose name this Note (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 the Holder of this Note not less than 10 days prior
to such Special Record Date, or may be paid at any time in any other lawful
manner, all as more fully provided in the Indenture.

          The Notes are, and all other Securities issued under the Indenture
will be, unconditionally guaranteed as to payment of principal (and premium,
if any), interest, if any, and additional amounts, if any, by KeySpan
Corporation, a Delaware corporation (the "Guarantor").

          Payment of the principal of (and premium, if any) and interest on
this Note will be made at the office or agency of the Company maintained by
the Company for such purpose in the Borough of Manhattan, The City of New
York, 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.

          Unless the certificate of authentication hereon has been executed
by or on behalf of The Chase Manhattan Bank, the Trustee with respect to the
Notes under the Indenture, or its successor thereunder, by the manual
signature of one of its authorized officers, this Note shall not be entitled
to any benefit under the Indenture or be valid or obligatory for any purpose.

          This Note is one of a duly authorized issue of Securities
(hereinafter called the "Securities") of the Company designated as its
Medium-Term Notes, Series A (the "Notes").  The Securities are issued and to
be issued under an indenture (the "Indenture") dated as of December 1, 1999,
between the Company, the Guarantor and The Chase Manhattan Bank (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 thereunder
of the Company, the Guarantor, the Trustee and the Holders of the Notes and
the terms upon which the Notes are to be authenticated and delivered.  The
terms of other Notes may vary with respect to interest rates or interest rate
formulas, issue dates, maturity, redemption, repayment, currency of payment
and otherwise as provided in the Indenture.

                                      -6-

<PAGE>

          The Notes are issuable only in registered form without coupons in
denominations of, unless otherwise specified above, $1,000 and integral
multiples thereof.  As provided in the Indenture and subject to certain
limitations therein set forth, the Notes are exchangeable for a like
aggregate principal amount of Notes as requested by the Holder surrendering
the same.  If (x) the Depository is at any time unwilling or unable to
continue as depository and a successor depository is not appointed by the
Company within 90 days, (y) the Company executes and delivers to the Trustee
a Company Order to the effect that this Note shall be exchangeable or (z) an
Event of Default has occurred and is continuing with respect to the Notes,
this Note shall be exchangeable for Notes in definitive form of like tenor
and in an equal aggregate principal amount, in authorized denominations.
Such definitive Notes shall be registered in such name or names as the
Depository shall instruct the Trustee.  If definitive Notes are so delivered,
the Company may make such changes to the form of this Note as are necessary
or appropriate to allow for the issuance of such definitive Notes.

          This Note is not subject to any sinking fund.

          This Note may be subject to repayment at the option of the Holder
prior to its Stated Maturity on the Holder's Optional Repayment Date(s), if
any, indicated on the face hereof.  If no Holder's Optional Repayment Dates
are set forth on the face hereof, this Note may not be so repaid at the
option of the Holder hereof prior to the Stated Maturity.  On any Holder's
Optional Repayment Date, this Note shall be repayable in whole or in part in
an amount equal to $1,000 or integral multiples thereof (provided that any
remaining principal amount shall be an authorized denomination) at the option
of the Holder hereof at a repayment price equal to 100% of the principal
amount to be repaid, together with interest thereon payable to the date of
repayment.  For this Note to be repaid in whole or in part at the option of
the Holder hereof, this Note must be received, with the form entitled "Option
to Elect Repayment" below duly completed, by the Trustee at its office at 450
West 33rd Street, 15th Floor, New York, New York 10001 or such address which
the Company shall from time to time notify the Holders of the Medium-Term
Notes (the "Corporate Trust Office"), not more than 60 nor less than 30 days
prior to a Holder's Optional Repayment Date.  This Note must be received by
the Trustee by 5:00 P.M., New York City time, on the last day for giving such
notice.  Exercise of such repayment option by the Holder hereof shall be
irrevocable.  In the event of payment of this Note in part only, a new Note
for the unpaid portion hereof shall be issued in the name of the Holder
hereof upon the surrender hereof.

          This Note may be redeemed at the option of the Company prior to its
Stated Maturity on any date on and after the Initial Redemption Date, if any,
specified on the face hereof (the "Redemption Date").  If no Initial
Redemption Date is set forth above, this Note may not be redeemed at the
option of the Company prior to the Stated Maturity.  On and after the Initial

                                      -7-

<PAGE>

Redemption Date, if any, this Note may be redeemed at any time in whole or
from time to time in part in increments of $1,000 or integral multiples
thereof (provided that any remaining principal amount shall be an authorized
denomination) at the option of the Company at the applicable Redemption Price
(as defined below) together with interest thereon payable to the Redemption
Date, on notice given not more than 60 nor less than 30 days prior to the
Redemption Date.  In the event of redemption of this Note in part only, a new
Note for the unredeemed portion hereof shall be issued in the name of the
Holder hereof upon the surrender hereof.

          If this Note is redeemable at the option of the Company prior to
its Stated Maturity, the "Redemption Price" shall initially be the Initial
Redemption Percentage, specified above, of the principal amount of this Note
to be redeemed and shall decline at each anniversary of the Initial
Redemption Date by the Annual Redemption Percentage Reduction, if any,
specified above, of the principal amount to be redeemed until the Redemption
Price is 100% of such principal amount.

          The interest rate borne by this Note shall be determined as
follows:

          I.  If this Note is designated as a Regular Floating Rate Note
     above, then, except as described below, this Note shall bear interest at
     the rate determined by reference to the applicable Interest Rate Basis
     or Bases shown above (1) plus or minus the applicable Spread, if any,
     and/or (2) multiplied by the applicable Spread Multiplier, if any,
     specified and applied in the manner described above; provided, however,
     that the interest rate in effect for the period from the Original Issue
     Date to the first Interest Reset Date shall be the Initial Interest
     Rate.  Commencing on the first Interest Reset Date, the rate at which
     interest on this Note is payable shall be reset as of each Interest
     Reset Date specified above.

          2.   If this Note is designated as a Floating Rate/Fixed Rate Note
     above, then, except as described below, this Note shall bear interest at
     the rate determined by reference to the applicable Interest Rate Basis
     or Bases shown above (1) plus or minus the applicable Spread, if any,
     and/or (2) multiplied by the applicable Spread Multiplier, if any,
     specified and applied in the manner described above; provided, however,
     that the interest rate in effect for the period from the Original Issue
     Date to the first Interest Reset Date will be the Initial Interest Rate.
     Commencing on the first Interest Reset Date, the rate at which interest
     on this Note is payable shall be reset as of each Interest Reset Date
     specified above; provided, however, that the interest rate in effect
     commencing on, and including, the date on which interest begins to
     accrue on a fixed rate basis to Maturity shall be the Fixed Interest
     Rate, if the rate is specified above, or if no Fixed Interest Rate is

                                      -8-

<PAGE>

     specified, the interest rate in effect on the Floating Rate/Fixed Rate
     Note on the day immediately preceding the date on which interest begins
     to accrue on a fixed rate basis.

          3.   If this Note is designated as an Inverse Floating Rate Note
     above, then, except as described below, this Note shall bear interest
     equal to the Fixed Interest Rate specified above minus the rate
     determined by reference to the applicable Interest Rate Basis or Bases
     shown above (1) plus or minus the applicable Spread, if any, and/or (2)
     multiplied by the applicable Spread Multiplier, if any, specified and
     applied in the manner described above; provided, however, that unless
     otherwise specified on the face hereof, the interest rate hereon shall
     not be less than zero percent; provided, however, that the interest rate
     in effect for the period from the Original Issue Date to the Initial
     Interest Reset Date shall be the Initial Interest Rate.  Commencing on
     the first Interest Reset Date, the rate at which interest on this Note
     is payable shall be reset as of each Interest Reset Date specified
     above.

          4.   Notwithstanding the foregoing, if this Note is designated
     above as having an Addendum attached or as having Other Provisions
     apply, the Note shall bear interest in accordance with the terms
     described in such Addendum or specified under Other Provisions.

          Except as provided above, the interest rate in effect on each day
shall be (a) if such day is an Interest Reset Date, the interest rate
determined as of the Interest Determination Date (as defined below)
immediately preceding such Interest Reset Date or (b) if such day is not an
Interest Reset Date, the interest rate determined as of the Interest
Determination Date immediately preceding the immediately preceding Interest
Reset Date.  Each Interest Rate Basis shall be determined in accordance with
the applicable provision below.  If any Interest Reset Date (which term
includes the term first Interest Reset Date unless the context otherwise
requires) would otherwise be a day that is not a Business Day, that Interest
Reset Date shall be postponed to the next succeeding day that is a Business
Day, except that if an Interest Rate Basis specified on the face hereof is
LIBOR and the next Business Day falls in the next succeeding calendar month,
that Interest Reset Date shall be the immediately preceding Business Day.  In
addition, if an Interest Rate Basis specified on the face hereof is the
Treasury Rate and the Interest Determination Date would otherwise fall on an
Interest Reset Date, then that Interest Reset Date shall be postponed to the
next succeeding Business Day.

          Unless otherwise specified above, interest payable on this Note on
any Interest Payment Date shall be the amount of interest accrued from and
including the immediately preceding Interest Payment Date in respect of which
interest has been paid (or from and including the Original Issue Date

                                      -9-

<PAGE>

specified above, if no interest has been paid), to but excluding the related
Interest Payment Date; provided, however, that the interest payments on
Maturity shall include interest accrued to but excluding such Maturity.
Unless otherwise specified above, accrued interest hereon shall be an amount
calculated by multiplying the face amount hereof by an accrued interest
factor.  The accrued interest factor shall be computed by adding the interest
factor calculated for each day from the date of issue or from the last date
to which interest shall have been paid or duly provided for, to the date for
which accrued interest is being calculated.  Unless otherwise specified
above, the interest factor for each such day shall be computed by dividing
the interest rate applicable to such day by 360, if the Day Count Convention
specified above is "Actual/360" for the period specified thereunder or by the
actual number of days in the year if the Day Count Convention specified above
is "Actual/Actual" for the period specified thereunder.  In the case of Notes
for which the Interest Rate Basis is the CD Rate, the Commercial Paper Rate,
the Eleventh District Cost of Funds Rate, the Federal Funds Rate, LIBOR or
the Prime Rate, the interest factor for each day will be computed by dividing
the interest rate applicable to each day by 360.  In the case of Notes for
which the Interest Rate Basis is the CMT Rate or the Treasury Rate, the
interest factor for each day will be computed by dividing the interest rate
applicable to each day by the actual number of days in the year.  The
interest factor for Notes for which the interest rate is calculated with
reference to two or more Interest Rate Bases will be calculated in each
period in the same manner as if only one of the applicable Interest Rate
Bases applied.

          Unless otherwise specified above, the "Interest Determination Date"
with respect to the CD Rate, the CMT Rate and the Commercial Paper Rate shall
be the second Business Day preceding each Interest Reset Date; the "Interest
Determination Date" with respect to the Federal Funds Rate and the Prime Rate
shall be the Business Day immediately preceding each Interest Reset Date; the
"Interest Determination Date" with respect to LIBOR shall be the second
London Business Day (as defined below) preceding each Interest Reset Date;
the "Interest Determination Date" with respect to the Eleventh District Cost
of Funds Rate shall be the last working day of the month immediately
preceding each Interest Reset Date on which the Federal Home Loan Bank of San
Francisco (the "FHLB of San Francisco") publishes the Index (as defined
below); and the "Interest Determination Date" with respect to the Treasury
Rate shall be the day in the week in which the related Interest Reset Date
falls on which day Treasury bills (as defined below) are normally auctioned.
Treasury bills are normally sold at auction on Monday of each week, unless
that day is a legal holiday, in which case the auction is normally held on
the following Tuesday, except that the auction may be held on the preceding
Friday; provided, however, that if an auction is held on the Friday of the
week preceding the related Interest Reset Date, the related Interest
Determination Date shall be such preceding Friday; and provided, further,
that if an auction shall fall on any Interest Reset Date, then the related

                                     -10-

<PAGE>

Interest Reset Date shall instead be the first Business Day following such
auction.  If the interest rate of this Note is determined with reference to
two or more Interest Rate Bases, the Interest Determination Date pertaining
to this Note shall be the latest Business Day which is at least two Business
Days prior to such Interest Reset Date on which each Interest Rate Basis
shall be determinable.  Each Interest Rate Basis shall be determined and
compared on such date, and the applicable interest rate shall take effect on
the related Interest Reset Date.

          Unless otherwise specified above, the "Calculation Date", if
applicable, pertaining to any Interest Determination Date shall be the
earlier of (i) the tenth calendar day after such Interest Determination Date
or, if such day is not a Business Day, the next succeeding Business Day, or
(ii) the Business Day preceding the applicable Interest Payment Date or date
of Maturity, as the case may be.  All calculations on this Note shall be made
by the calculation agent specified above or such successor thereto as is duly
appointed by the Company.

          All percentages resulting from any calculation on this Note will be
rounded to the nearest one hundred-thousandth of a percentage point, with
five one-millionths of a percentage point rounded upwards.  For example,
9.876545% or .09876545 would be rounded to 9.87655% or .0987655.  All dollar
amounts used in or resulting from such calculation will be rounded to the
nearest cent with one-half cent being rounded upward.

          As used herein, "Business Day" means any day, other than a Saturday
or Sunday, that is neither a legal holiday nor a day on which commercial
banks are authorized or required by law, regulation or executive order to
close in The City of New York; provided, however, that, with respect to
non-United State dollar denominated Notes, such day is also not a day on
which commercial banks are authorized or required by law, regulation or
executive order to close in the Principal Financial Center (as hereinafter
defined) of the country issuing the Specified Currency or, if the Specified
Currency is EURO, the day is also a day on which the Trans-European Automated
Real-Time Gross Settlement Express Transfer (TARGET) System is open;
provided, further, that, with respect to Notes as to which LIBOR is an
applicable Interest Rate Basis, such day is also a London Business Day.

          As used herein, "London Business Day" means a day on which
commercial banks are open for business, including dealings in the LIBOR
Currency (as hereinafter defined), in London.

          As used herein, Principal Financial Center means, unless otherwise
specified in the applicable pricing supplement,

     -    the capital city of the country issuing the Specified Currency,
          except that with respect to United States dollars, Australian

                                     -11-

<PAGE>

          dollars, Canadian dollars, Deutsche marks, Dutch guilders, South
          African rand and Swiss francs, the "Principal Financial Center"
          will be The City of New York, Sydney and Melbourne, Toronto,
          Frankfurt, Amsterdam, Johannesburg and Zurich, respectively, or

     -    the capital city of the country to which the LIBOR Currency, as
          defined below, relates, except that with respect to United States
          dollars, Canadian dollars, Deutsche marks, Dutch guilders,
          Portuguese escudos, South African rand and Swiss francs, the
          "Principal Financial Center" will be The City of New York, Toronto,
          Frankfurt, Amsterdam, London, Johannesburg and Zurich,
          respectively.

          Determination of CD Rate.   If an Interest Rate Basis for this Note
is the CD Rate, as indicated above, the CD Rate shall be determined on the
applicable Interest Determination Date as:

          (1)  the rate on the applicable Interest Determination Date for
               negotiable United States dollar certificates of deposit having
               the Index Maturity specified above published in H.15(519)
               under the heading "CDs (secondary market)", or

          (2)  if the rate referred to in clause (1) above is not so
               published by 3:00 P.M., New York City time, on the related
               Calculation Date, the rate on the applicable Interest
               Determination Date for negotiable United States dollar
               certificates of deposit of the Index Maturity specified above
               as published in H.15 Daily Update, or other recognized
               electronic source used for the purpose of displaying the
               applicable rate, under the caption "CDs (secondary market)",
               or

          (3)  if the rate referred to in clause (2) is not so published by
               3:00 P.M., New York City time, on the related Calculation
               Date, the rate on the applicable Interest Determination Date
               calculated by the calculation agent as the arithmetic mean of
               the secondary market offered rates as of 10:00 A.M., New York
               City time, on the applicable Interest Determination Date, of
               three leading non-bank dealers in negotiable United States
               dollar certificates of deposit in The City of New York
               selected by the calculation agent for negotiable United States
               dollar certificates of deposit of major United States money
               center banks for negotiable certificates of deposit with a
               remaining maturity closest to the Index Maturity specified
               above in an amount that is representative for a single
               transaction in that market at that time, or

                                     -12-

<PAGE>

          (4)  if the dealers selected by the calculation agent are not
               quoting as mentioned in clause (3) above, the CD rate in
               effect on the applicable Interest Determination Date.

          "H.15(519)" means the weekly statistical release designated as
H.15(519), or any successor publication, published by the Board of Governors
of the Federal Reserve System.

          "H.15 Daily Update" means the daily update of H.15(519), available
through the world-wide-web site of the Board of Governors of the Federal
Reserve System at http://www.bog.frb.fed.us/releases/h15/update, or any
successor site or publication.

          Determination of CMT Rate.   If an Interest Rate Basis for this
Note is the CMT Rate, as indicated above, the CMT Rate shall be determined as
of the applicable Interest Determination Date as:

          (1)  the rate displayed on the Designated CMT Telerate Page under
               the caption "...Treasury Constant Maturities...  Federal
               Reserve Board Release H.15...  Mondays Approximately 3:45
               P.M.", under the column for the Designated CMT Maturity Index
               for:

               (a)  if the Designated CMT Telerate Page is 7051, the rate on
                    the applicable Interest Determination Date, and

               (b)  if the Designated CMT Telerate Page is 7052, the weekly
                    or the monthly average, as specified above, for the week
                    or the month, as applicable, ended immediately preceding
                    the week or the month, as applicable, in which the
                    related Interest Determination Date falls, or

          (2)  if the rate referred to in clause (1) is no longer displayed
               on the relevant page or is not so displayed by 3:00 P.M., New
               York City time, on the related Calculation Date, the treasury
               constant maturity rate for the Designated CMT Maturity Index
               published in H.15(519), or

          (3)  if the rate referred to in clause (2) is no longer published
               or is not published by 3:00 P.M., New York City time, on the
               related Calculation Date, the treasury constant maturity rate
               for the Designated CMT Maturity Index, or other United States
               Treasury rate for the Designated CMT Maturity Index, for the
               applicable Interest Determination Date with respect to the
               applicable Interest Reset Date as may then be published by
               either the Board of Governors of the Federal Reserve System or
               the United States Department of the Treasury that the

                                     -13-

<PAGE>

               calculation agent determines to be comparable to the rate
               formerly displayed on the Designated CMT Telerate Page and
               published in H.15(519), or

          (4)  if the rate referred to in clause (3) applicable information
               is not so published by 3:00 P.M., New York City time, on the
               applicable Calculation Date, the rate on the applicable
               Interest Determination Date calculated by the calculation
               agent as a yield to maturity, based on the arithmetic mean of
               the secondary market offered rates as of approximately 3:30
               P.M., New York City time, on the applicable Interest
               Determination Date reported, according to their written
               records, by three leading primary United States government
               securities dealers in The City of New York, which may include
               the agent or its affiliates (each, a "Reference Dealer"),
               selected by the calculation agent from five Reference Dealers
               selected by the calculation agent after eliminating the
               highest quotation, or, in the event of equality, one of the
               highest, and the lowest quotation or, in the event of
               equality, one of the lowest, for the most recently issued
               direct noncallable fixed rate obligations of the United States
               ("Treasury Notes") with an original maturity of approximately
               the Designated CMT Maturity Index and a remaining term to
               maturity of not less than such Designated CMT Maturity Index
               minus one year, or

          (5)  if the calculation agent is unable to obtain three applicable
               Treasury Note quotations as referred to in clause (4), the
               rate on the applicable Interest Determination Date calculated
               by the calculation agent as a yield to maturity based on the
               arithmetic mean of the secondary market offered rates as of
               approximately 3:30 P.M., New York City time, on the applicable
               Interest Determination Date of three Reference Dealers in The
               City of New York selected by the calculation agent from five
               Reference Dealers selected by the calculation agent after
               eliminating the highest quotation or, in the event of
               equality, one of the highest and the lowest quotation or, in
               the event of equality, one of the lowest, for Treasury Notes
               with an original maturity of the number of years that is the
               next highest to the Designated CMT Maturity Index and a
               remaining term to maturity closest to the Designated CMT
               Maturity Index and in an amount of at least $100 million, or

          (6)  if three or four and not five Reference Dealers are quoting as
               referred to in clause (5) above, the rate will be calculated
               by the calculation agent as the arithmetic mean of the offered

                                     -14-

<PAGE>

               rates obtained and neither the highest nor the lowest of
               quotes will be eliminated, or

          (7)  if fewer than three Reference Dealers selected by the
               calculation agent are quoting as mentioned in clause (6), the
               rate in effect on the applicable Interest Determination Date.

               If two Treasury Notes with an original maturity as described
          in clause (5) have remaining terms to maturity equally close to the
          Designated CMT Maturity Index, the calculation agent will obtain
          from five Reference Dealers quotations for the Treasury Notes with
          the shorter remaining term to maturity.

          "Designated CMT Telerate Page" means the display on Bridge
Telerate, Inc.  or any successor service on the page specified above or any
other page as may replace the specified page on that service for the purpose
of displaying Treasury Constant Maturities as reported in H.15(519), or, if
no page is specified above, page 7052.

          "Designated CMT Maturity Index" means the original period to
maturity of the U.S.  Treasury securities, either 1, 2, 3, 5, 7, 10, 20 or 30
years, specified above with respect to which the CMT Rate will be calculated
or, if no maturity is specified above, 2 years.

          Determination of Commercial Paper Rate.   If an Interest Rate Basis
for this Note is the Commercial Paper Rate, as indicated above, the
Commercial Paper Rate shall be determined on the applicable Interest
Determination Date as:

          (1)  the Money Market Yield on the applicable Interest
               Determination Date of the rate for commercial paper having the
               Index Maturity specified above published in H.15(519) under
               the caption "Commercial Paper-Nonfinancial", or

          (2)  if the rate described in clause (1) is not so published by
               3:00 P.M., New York City time, on the related Calculation
               Date, the rate on the applicable Interest Determination Date
               for commercial paper having the Index Maturity specified above
               published in H.15 Daily Update, or other recognized electronic
               source used for the purpose of displaying the applicable rate,
               under the caption "Commercial Paper-Nonfinancial", or

          (3)  if the rate referred to in clause (2) is not so published by
               3:00 P.M., New York City time, on the related Calculation
               Date, the rate on the applicable Interest Determination Date
               calculated by the calculation agent as the Money Market Yield
               of the arithmetic mean of the offered rates at approximately

                                     -15-

<PAGE>

               11:00 A.M., New York City time, on the applicable Interest
               Determination Date of three leading dealers of United States
               dollar commercial paper in The City of New York, which may
               include the calculation agent and its affiliates, selected by
               the calculation agent for commercial paper having the Index
               Maturity specified above placed for industrial issuers whose
               bond rating is "Aa", or the equivalent, from a nationally
               recognized statistical rating organization, or

          (4)  if the dealers selected by the calculation agent are not
               quoting as mentioned in clause (3), the rate in effect on the
               applicable Interest Determination Date.

          "Money Market Yield" means a yield calculated in accordance with
the following formula and expressed as a percentage:

            Money Market Yield   =            D x 360        x 100
                                         ------------------
                                           360 - ( D x M )

where "D" refers to the applicable per annum rate for commercial paper quoted
on a bank discount basis and expressed as a decimal, and "M" refers to the
actual number of days in the interest period for which interest is being
calculated.

          Eleventh District Cost of Funds Rate.   If an Interest Rate Basis
for this Note is the Eleventh District Cost of Funds Rate, as indicated
above, the Eleventh District Cost of Funds Rate shall be determined on the
applicable Interest Determination Date and shall be:

          (1)  the rate equal to the monthly weighted average cost of funds
               for the calendar month immediately preceding the month in
               which the applicable Interest Determination Date falls as set
               forth under the caption "11th District" on the display on
               Bridge Telerate, Inc.  or any successor service on page 7058
               or any other page as may replace the specified page on that
               service ("Telerate Page 7058") as of 11:00 A.M., San Francisco
               time, on the applicable Interest Determination Date, or

          (2)  if the rate referred to in clause (1) does not appear on
               Telerate Page 7058 on the related Interest Determination Date,
               the monthly weighted average cost of funds paid by member
               institutions of the Eleventh Federal Home Loan Bank District
               that was most recently announced (the "Index") by the Federal
               Home Loan Bank of San Francisco as the cost of funds for the

                                     -16-

<PAGE>

               calendar month immediately preceding the applicable Interest
               Determination Date, or

          (3)  if the Federal Home Loan Bank of San Francisco fails to
               announce the Index on or before the applicable Interest
               Determination Date for the calendar month immediately
               preceding the applicable Interest Determination Date, the rate
               in effect on the applicable Interest Determination Date.

          Determination of Federal Funds Rate.   If an Interest Rate Basis
for this Note is the Federal Funds Rate, as indicated above, the Federal
Funds Rate shall be determined on the applicable Interest Determination Date
and shall be:

          (1)  the rate on the applicable Interest Determination Date for
               United States dollar federal funds as published in H.15(519)
               under the heading "Federal Funds (Effective)", as displayed on
               Bridge Telerate, Inc.  or any successor service on page 120 or
               any other page as may replace the applicable page on that
               service ("Telerate Page 120"), or

          (2)  if the rate referred to in clause (1) does not appear on
               Telerate Page 120 or is not so published by 3:00 P.M., New
               York City time, on the related Calculation Date, the rate on
               the applicable Interest Determination Date for United States
               dollar federal funds published in H.15 Daily Update, or other
               recognized electronic source used for the purpose of
               displaying the applicable rate, under the caption "Federal
               Funds/Effective Rate", or

          (3)  if the rate referred to in clause (2) is not so published by
               3:00 P.M., New York City time, on the related Calculation
               Date, the rate on the applicable Interest Determination Date
               calculated by the calculation agent as the arithmetic mean of
               the rates for the last transaction in overnight United States
               dollar federal funds arranged by three leading brokers of
               United States dollar federal funds transactions in The City of
               New York, which may include the agent or its affiliates,
               selected by the calculation agent before 9:00 A.M., New York
               City time, on the applicable Interest Determination Date, or

          (4)  if the brokers selected by the calculation agent are not
               quoting as mentioned in clause (3), the rate in effect on the
               applicable Interest Determination Date.

                                     -17-

<PAGE>

          Determination of LIBOR.  If an Interest Rate Basis for this Note is
LIBOR, as indicated above, LIBOR shall be determined by the calculation agent
in accordance with the following provisions:

          (1)  if "LIBOR Telerate" is specified above or if neither "LIBOR
               Reuters" nor "LIBOR Telerate" is specified above as the method
               for calculating LIBOR, LIBOR will be the rate for deposits in
               the LIBOR Currency, as defined below, having the Index
               Maturity specified above, commencing on the second London
               Business Day immediately following that Interest Determination
               Date that appears on the Designated LIBOR Page as of 11:00
               A.M., London time, on the applicable Interest Determination
               Date, or

          (2)  if "LIBOR Reuters" is specified above, LIBOR will be the
               arithmetic mean of the offered rates for deposits in the LIBOR
               Currency having the Index Maturity specified above, commencing
               on the second London Business Day immediately following that
               Interest Determination Date, that appear, on the Designated
               LIBOR Page specified above as of 11:00 A.M., London time, on
               the applicable Interest Determination Date.  If the Designated
               LIBOR Page by its terms provides only for a single rate, then
               the single rate will be used, or

          (3)  with respect to a LIBOR Interest Determination Date on which
               fewer than two offered rates appear, or no rate appears, as
               the case may be, on the designated LIBOR Page as specified in
               clauses (1) and (2) (except a Designated LIBOR Page which by
               its terms provides only for a single rate), the rate
               calculated by the calculation agent as the arithmetic mean of
               at least two quotations obtained by the calculation agent
               after requesting the principal London offices of each of four
               major reference banks, which may include affiliates of the
               agent, in the London interbank market to provide the
               calculation agent with its offered quotation for deposits in
               the LIBOR Currency for the period of the Index Maturity
               specified above, commencing on the second London Business Day
               immediately following the applicable Interest Determination
               Date, to prime banks in the London interbank market at
               approximately 11:00 A.M., London time, on the applicable
               Interest Determination Date and in a principal amount that is
               representative for a single transaction in the applicable
               LIBOR Currency in that market at that time, or

          (4)  if fewer than two quotations referred to in clause (3) are so
               provided, the rate on the applicable Interest Determination
               Date calculated by the calculation agent as the arithmetic

                                     -18-

<PAGE>

               mean of the rates quoted at approximately 11:00 A.M., in the
               applicable Principal Financial Center(s), on the applicable
               Interest Determination Date by three major banks, which may
               include affiliates of the calculation agent, in the applicable
               Principal Financial Center selected by the calculation agent
               for loans in the LIBOR Currency to leading European banks,
               having the Index Maturity specified designated above and in a
               principal amount that is representative for a single
               transaction in the applicable LIBOR Currency in that market at
               that time, or

          (5)  if the banks so selected by the calculation agent are not
               quoting as mentioned in clause (4), the rate in effect on the
               applicable Interest Determination Date.

          "LIBOR Currency" means the currency specified above as to which
LIBOR will be calculated or, if no currency is specified above, United States
dollars.

          "Designated LIBOR Page" means either:

          -     if "LIBOR Telerate" is designated above or neither "LIBOR
               Reuters" nor "LIBOR Telerate" is specified above as the method
               for calculating LIBOR, the display on Bridge Telerate, Inc.
               or any successor service on the page specified in such pricing
               supplement or any page as may replace the specified page on
               that service for the purpose of displaying the London
               interbank rates of major banks for the applicable LIBOR
               Currency, or

          -     if "LIBOR Reuters" is specified above, the display on the
               Reuter Monitor Money Rates Service or any successor service on
               the page specified above or any other page as may replace the
               specified page on that service for the purpose of displaying
               the London interbank rates of major banks for the applicable
               LIBOR Currency.

          Determination of Prime Rate.  If an Interest Rate Basis for this
Note is the Prime Rate, as indicated above, the Prime Rate shall be
determined on the applicable Interest Determination Date and shall be:

          (1)  the rate on the applicable Interest Determination Date as
               published in H.15(519) under the heading "Bank Prime Loan", or

          (2)  if the rate referred to in clause (1) is not so published by
               3:00 P.M., New York City time, on the related Calculation
               Date, the rate on the applicable Interest Determination Date

                                     -19-

<PAGE>

               published in H.15 Daily Update, or such other recognized
               electronic source used for the purpose of displaying the
               applicable rate under the caption "Bank Prime Loan", or

          (3)  if the rate referred to in clause (2) is not so published by
               3:00 P.M., New York City time, on the related Calculation
               Date, the rate calculated by the calculation agent as the
               arithmetic mean of the rates of interest publicly announced by
               at least four banks that appear on the Reuters Screen US PRIME
               1 Page as the particular bank's prime rate or base lending
               rate as of 11:00 A.M., New York City time, on the applicable
               Interest Determination Date, or

          (4)  if fewer than four rates described in clause (2) by 3:00 P.M.,
               New York City time, on the related Calculation Date as shown
               on Reuters Screen US PRIME 1, the rate on the applicable
               Interest Determination Date calculated by the calculation
               agent as the arithmetic mean of the prime rates or base
               lending rates quoted on the basis of the actual number of days
               in the year divided by a 360-day year as of the close of
               business on the applicable Interest Determination Date by
               three major banks, which may include affiliates of the agent,
               in The City of New York selected by the calculation agent, or

          (5)  if the banks selected by the calculation agent are not quoting
               as mentioned in clause (4), the rate in effect on the
               applicable Interest Determination Date.

          "Reuters Screen US PRIME 1 Page" means the display on the Reuter
Monitor Money Rates Service or any successor service on the "US PRIME 1" Page
or other page as may replace the US PRIME 1 Page on such service for the
purpose of displaying prime rates or base lending rates of major United
States banks.

          Determination of Treasury Rate.   If an Interest Rate Basis for
this Note is the Treasury Rate, as specified above, the Treasury Rate shall
be determined on the applicable Interest Determination Date and shall be:

          (1)  the rate from the auction held on the applicable Interest
               Determination Date (the "Auction") of direct obligations of
               the United States ("Treasury Bills") having the Index Maturity
               specified above under the caption "INVESTMENT RATE" on the
               display on Bridge Telerate, Inc.  or any successor service on
               page 56 or any other page as may replace page 56 on that
               service ("Telerate Page 56") or page 57 or any other page as
               may replace page 57 on that service ("Telerate Page 57"), or

                                     -20-

<PAGE>

          (2)  if the rate described in clause (1) is not so published by
               3:00 P.M., New York City time, on the related Calculation
               Date, the Bond Equivalent Yield of the rate for the applicable
               Treasury Bills as published in H.15 Daily Update, or other
               recognized electronic source used for the purpose of
               displaying the applicable rate, under the caption "U.S.
               Government Securities/Treasury Bills/Auction High", or

          (3)  if the rate described in clause (2) is not so published by
               3:00 P.M., New York City time, on the related Calculation
               Date, the Bond Equivalent Yield of the auction rate of the
               applicable Treasury Bills announced by the United States
               Department of the Treasury, or

          (4)  if the rate referred to in clause (3) is not announced by the
               United States Department of the Treasury, or if the Auction is
               not held, the Bond Equivalent Yield of the rate on the
               applicable Interest Determination Date of Treasury Bills
               having the Index Maturity specified above published in
               H.15(519) under the caption "U.S.  Government
               Securities/Treasury Bills/Secondary Market", or

          (5)  if the rate referred to in clause (4) is not so published by
               3:00 P.M., New York City time, on the related Calculation
               Date, the rate on the applicable Interest Determination Date
               of the applicable Treasury Bills as published in H.15 Daily
               Update, or other recognized electronic source used for the
               purpose of displaying the applicable rate, under the caption
               "U.S.  Government Securities/Treasury Bills/Secondary Market",
               or

          (6)  if the rate referred to in clause (5) is not so published by
               3:00 P.M., New York City time, on the related Calculation
               Date, the rate on the applicable Interest Determination Date
               calculated by the calculation agent as the Bond Equivalent
               Yield of the arithmetic mean of the secondary market bid
               rates, as of approximately 3:30 P.M., New York City time, on
               the applicable Interest Determination Date, of three primary
               United States government securities dealers, which may include
               the agent or its affiliates, selected by the calculation
               agent, for the issue of Treasury Bills with a remaining
               maturity closest to the Index Maturity specified above, or

          (7)  if the dealers selected by the calculation agent are not
               quoting as mentioned in clause (6), the rate in effect on the
               applicable Interest Determination Date.

                                     -21-

<PAGE>

          "Bond Equivalent Yield" means a yield calculated in accordance with
the following formula and expressed as a percentage:

 Bond Equivalent Yield  =            D x N           x  100
                                -----------------
                                 360 - ( D x M )

where "D" refers to the applicable per annum rate for Treasury Bills quoted
on a bank discount basis, "N" refers to 365 or 366, as the case may be, and
"M" refers to the actual number of days in the interest period for which
interest is being calculated.

          Any provisions contained herein with respect to the determination
of one or more Interest Rate Bases, the specification of one or more Interest
Rate Bases, calculation of the Interest Rate applicable to this Note, its
payment dates the stated maturity date, any redemption or repayment
provisions, or any other matter relating hereto may be modified by the terms
as specified above under "Other Provisions" or in an Addendum relating hereto
if so specified above.

          Notwithstanding the foregoing, the interest rate hereon shall not
be greater than the Maximum Interest Rate, if any, or less than the Minimum
Interest Rate, if any, specified above.  The calculation agent shall
calculate the interest rate hereon in accordance with the foregoing on or
before each Calculation Date.  The Company hereby covenants for the benefit
of the Holder hereof, to the extent permitted by applicable law, not to claim
voluntarily the benefits of any laws concerning usurious rates of interest
against such Holder.

          Unless stated otherwise above, Merrill Lynch, Pierce, Fenner &
Smith Incorporated will be the calculation agent.  At the request of the
Holder hereof, the calculation agent shall provide to the Holder hereof the
interest rate hereon then in effect and, if determined, the interest rate
which shall become effective as of the next Interest Reset Date with respect
to this Note.

          If an Event of Default (as defined in the Indenture) with respect
to the Notes of this series shall occur and be continuing, the principal of
all of the Notes may be declared due and payable in the manner and with the
effect provided in the Indenture.  If the principal of any Original Issue
Discount Note is declared to be due and payable immediately, the amount of
principal due and payable with respect to such Note shall be limited to the
amount equal to (i) the sum of the aggregate principal amount of such Note
multiplied by the price (expressed as a percentage of the aggregate principal
amount) at which such Note will be issued (the "Issue Price") plus (ii) the
original issue discount accrued from the date of issue to the date of
declaration, which accrual shall be calculated using the "interest method"

                                     -22-

<PAGE>

computed in accordance with generally accepted accounting principles in
effect on the date of declaration.  An "Original Issue Discount Note" means
(i) a Note, including any zero-coupon Note, that has a stated redemption
price at maturity that exceeds the initial offering price to the public at
which a substantial amount of an offering is sold by at least 0.25% of its
principal amount multiplied by the number of full years from the Original
Issue Date to the Stated Maturity for such Note and which is designated as an
Original Issue Discount Note in the terms of such Note pursuant to the
Indenture, and (ii) any other Note designated by the Company as issued with
original issue discount for United States federal income tax purposes.

          The Indenture permits, with certain exceptions as therein provided,
the amendment or modification thereof at any time by the Company, the
Guarantor and the Trustee with the consent of the Holders of more than 50% in
principal amount of the Securities at the time outstanding of each series
issued under the Indenture to be affected thereby.  The Indenture also
contains provisions permitting the Holders of more than 50% in principal
amount of the Securities of each series at the time outstanding, on behalf of
the Holders of all Securities of that series, to waive compliance by the
Company and the Guarantor with certain provisions of the Indenture and
certain past defaults under the Indenture and their consequences with respect
to such series.  Any such consent or waiver by the Holder of this Note shall
be conclusive and binding upon such Holder and upon all future Holders of
this Note and of any Note 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 Note.

          No reference herein to the Indenture and no provision of this Note
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 Note at the time, place and rate, and in the coin
or currency, herein and in the Indenture prescribed.

          As provided in the Indenture and subject to certain limitations set
forth therein and on the face hereof, the transfer of this Note may be
registered on the Security Register of the Company, upon surrender of this
Note for registration of transfer at the office or agency of the Company in
the Borough of Manhattan, The City of New York, duly endorsed by, or
accompanied by a written instrument of transfer in form satisfactory to the
Company duly executed by, the Holder hereof or by his attorney duly
authorized in writing, and thereupon one or more new Notes of authorized
denominations and for the same aggregate principal amount, and having
endorsed thereon a Guarantee duly executed by the Guarantor, 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

                                     -23-

<PAGE>

to cover any tax or other governmental charge payable in connection
therewith.

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

          Certain of the Company's and the Guarantor's obligations under the
Indenture with respect to Notes of any series may be terminated if the
Company or the Guarantor irrevocably deposits with the Trustee money or
Government Obligations sufficient to pay and discharge the entire
indebtedness on all Notes of such series, as provided in the Indenture.

          The Indenture and the Notes shall be governed by and construed in
accordance with the laws of the State of New York.

          All terms used in this Note which are defined in the Indenture
shall have the meanings assigned to them in the Indenture.

                                     -24-

<PAGE>

          IN WITNESS WHEREOF, the Company has caused this instrument to be
duly executed, manually or in facsimile, and an imprint or facsimile of its
corporate seal to be imprinted hereon.

Dated: ____________

KEYSPAN GAS EAST CORPORATION

By:___________________________________
   [Name and Title]

[FACSIMILE OF SEAL]

Attest:

By: ___________________________
    [Name and Title]

CERTIFICATE OF AUTHENTICATION
This is one of the Securities of the
series designated therein referred to
in the within-mentioned Indenture.

THE CHASE MANHATTAN BANK,
      as Trustee

By: __________________________
    Authorized Officer

                                     -25-

<PAGE>

                           OPTION TO ELECT REPAYMENT

          The undersigned hereby irrevocably request(s) and instruct(s) the
Company to repay this Note (or portion hereof specified below) pursuant to
its terms at a price equal to the principal amount hereof together with
interest to the repayment date, to the undersigned, at

---------------------------------------------------------------------------
     (Please print or typewrite name and address of the undersigned)

          For this Note to be repaid, the Trustee must receive at its
Corporate Trust Office, or at such other place or places of which the Company
shall from time to time notify the Holder of this Note, not more than 60 nor
less than 30 days prior to an Optional Repayment Date, if any, shown on the
face of this Note, this Note with this "Option to Elect Repayment" form duly
completed.  This Note must be received by the Trustee by 5:00 P.M., New York
City time, on the last day for giving such notice.

          If less than the entire principal amount of this Note is to be
repaid, specify the portion hereof (which shall be in an amount equal to
$1,000 or an integral multiple thereof, provided that any remaining principal
amount shall be an authorized denomination) which the Holder elects to have
repaid and specify the denomination or denominations (which shall be in an
amount equal to an authorized denomination) of the Notes to be issued to the
Holder for the portion of this Note not being repaid (in the absence of any
such specification, one such Note will be issued for the portion not being
repaid).

$____________________    ____________________________________________________
                          NOTICE: The signature on this Option to Elect Date
                          Repayment must correspond with the name as  written
                          upon the face of this Note in every particular,
                          without alteration or enlargement or any change
                          whatever.

Date _________________

                                     -26-

<PAGE>

                           ASSIGNMENT/TRANSFER FORM

          FOR VALUE RECEIVED the undersigned registered Holder hereby
sell(s), assign(s) and transfer(s) unto (insert Taxpayer Identification No.)
____________________________________________________________________________
____________________________________________________________________________
(Please print or typewrite name and address including postal zip code of
assignee)
___________________________________________________________________________
the within Note and all rights thereunder, hereby irrevocably constituting
and appointing _______________________________________ attorney to transfer
said Note on the books of the Company with full power of substitution in the
premises.

Date:________________     _________________________________________________
                          NOTICE:  The  signature  of  the registered Holder
                          to this assignment must correspond with the name as
                          written upon the face of the within instrument  in
                          every  particular, without alteration or enlargement
                          or any change whatsoever.

                                     -27-

<PAGE>

                                   GUARANTEE

          FOR VALUE RECEIVED, KEYSPAN CORPORATION, a New York corporation
(the "Guarantor"), hereby fully and unconditionally guarantees to each Holder
of a Note authenticated and delivered by the Trustee, and to the Trustee on
behalf of each such Holder, the due and punctual payment of the principal of
(and premium, if any) and interest, if any, on each such Note, the due and
punctual payment of any sinking fund payments provided for pursuant to the
terms of such Note and the payment of any additional amounts when and as the
same shall become due and payable, whether at the Stated Maturity, by
declaration of acceleration, call for redemption or otherwise, in accordance
with the terms of such Note and of the Indenture, dated as of December 1,
1999 (the "Indenture") by and among Keyspan Gas East Corporation (the
"Issuer" or the "Company"), the Guarantor and The Chase Manhattan Bank, as
Trustee (the "Trustee").  In case of the failure of the Company punctually to
make any such payment of principal (or premium, if any) or interest, if any,
or sinking fund payment or payment of additional amounts, the Guarantor
hereby agrees to cause any such payment to be made punctually when and as the
same shall become due and payable, whether at the Stated Maturity or by
declaration of acceleration, call for redemption or otherwise, and as if such
payment were made by the Company.

          The Guarantor hereby agrees that its obligations hereunder shall be
unconditional, irrespective of the validity, regularity or enforceability of
such Note or the Indenture, the absence of any action to enforce the same,
any waiver or consent by the Holder of such Note or by the Trustee with
respect to any provisions thereof or of the Indenture, the obtaining of any
judgment against the Company or any action to enforce the same or any other
circumstances which might otherwise constitute a legal or equitable discharge
or defense of a guarantor.  The Guarantor hereby waives the benefits of
diligence, presentment, demand of payment, filing of claims with a court in
the event of insolvency or bankruptcy of the Company, any right to require a
proceeding first against the Company, protest or notice with respect to such
Note or the indebtedness evidenced thereby or with respect to any sinking
fund payment required pursuant to the terms of such Note and all demands
whatsoever, and covenants that this Guarantee will not be discharged except
by complete performance of the obligations contained in the Notes and in this
Guarantee.  This Guarantee is a guarantee of payment and not collection.  If
the Trustee or the Holder of any Note is required by any court or otherwise
to return to the Company or the Guarantor, or any custodian, receiver,
liquidator, trustee, sequestrator or other similar official acting in
relation to the Company or the Guarantor, any amount paid to the Trustee or
such Holder in respect of a Note, this Guarantee, to the extent theretofore
discharged, shall be reinstated in full force and effect.  The Guarantor
further agrees, to the fullest extent that it lawfully may do so, that, as
between the Guarantor on the one hand, and the Holders and the Trustee, on
the other hand, the maturity of the obligations guaranteed hereby may be

                                     -28-

<PAGE>

accelerated as provided in Article V of the Indenture for the purposes of
this Guarantee, notwithstanding any stay, injunction or other prohibition
extant under any applicable bankruptcy law preventing such acceleration in
respect of the obligations guaranteed hereby.

          The Guarantor shall be subrogated to all rights of the Holders of
the Notes of a particular series against the Company in respect of any amount
paid by the Guarantor on account of such Note pursuant to the provisions of
this Guarantee or the Indenture; provided, however, that the Guarantor shall
not be entitled to enforce or to receive any payments arising out of, or
based upon, such right of subrogation until the principal of (and premium, if
any) and interest, if any, on all Notes of such series issued hereunder shall
have been paid in full.

          The Guarantor hereby certifies and warrants that all acts,
conditions and things required to be done and performed and to have happened
prior to the creation and issuance of this Guarantee and to constitute the
same as the legal, valid and binding obligation of the Guarantor enforceable
in accordance with its terms, have been done and performed and have happened
in due and strict compliance with applicable laws.

          The delivery of any Note by the Trustee, after the authentication
thereof, shall constitute due delivery of this Guarantee endorsed thereon on
behalf of the Guarantor.  The Guarantor hereby agrees that this Guarantee
shall remain in full force and effect notwithstanding any failure to endorse
on each Note a notation of this Guarantee.

          This Guarantee shall be governed by and construed in accordance
with the laws of the State of New York.

          All terms used in this Guarantee which are defined in the Indenture
shall have the meanings assigned to them in the Indenture.

          IN WITNESS WHEREOF, KEYSPAN CORPORATION has caused this Guarantee
to be duly executed in its corporate name by the facsimile signature of one
of its officers thereunto duly authorized and has caused a facsimile of its
corporate seal to be affixed hereunto or imprinted or otherwise reproduced
hereon.

Dated as of:             , 2000

                               KEYSPAN CORPORATION

                               By:_________________________
                                     [Name and Title]

[FACSIMILE OF SEAL]

                                     -29-

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