Document:

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                                                                   Exhibit 10.16
                                                                   -------------

                               CONSENT TO SUBLEASE
                               -------------------

         A & W Virginia Corporation, an Arizona corporation ("Landlord"), as
successor in interest to GP Henrico, L.L.C., a Rhode Island Limited Liability
Company, is Landlord under a certain Building Lease dated October 10, 1995, as
amended by that certain First Amendment to Lease dated September 6, 1996
("Lease") pursuant to which Albright & Wilson Americas, Inc., a Delaware
corporation ("Albright"), leased Premises described in the Lease ("Premises").
Rhodia, Inc., a Delaware corporation ("Tenant") is successor in interest to
Albright.

         Tenant has requested Landlord's consent to sublease a portion of the
Premises to Insmed, Incorporated ("Subtenant"), a Virginia corporation. Landlord
hereby grants its consent to the sublease dated the 30th of March, 2001
between Tenant as Sublessor and Subtenant (the "Sublease") for a portion of the
Premises defined in the Sublease ("Sublease Premises") on the terms and
conditions stated in this Consent to Sublease.

         It is understood and agreed as follows:

         1.  This Consent to Sublease shall in no way release Tenant from any of
its covenants, agreements, liabilities and duties under the Lease. It is further
agreed that Tenant shall be responsible for the collection of all rent due it
from the Subtenant, and that the Landlord shall look only to Tenant as its
tenant.

         2.  The Sublease is, in all respects, subject to and subordinate to the
Lease and to all the terms and provisions contained in the Lease.

         3.  If, at any time prior to the expiration of the term of the
Sublease, the Lease shall terminate or be terminated for any reason, Subtenant
agrees, at the election and upon written demand of Landlord, to attorn to the
Landlord upon the then executory terms and conditions set forth in the Sublease
for the remainder of the term of the Sublease. The foregoing provisions of this
paragraph shall apply notwithstanding that as a matter of law, the Sublease may
otherwise terminate upon the termination of the Lease, and shall be
self-operative upon such written demand of the Landlord and no further
instrument shall be required to give effect to said provisions. Upon demand of
the Landlord, Subtenant agrees, however, to execute, from time to time,
document(s) in confirmation of the foregoing provisions of this paragraph
satisfactory to the Landlord, in which Subtenant shall acknowledge such
attornment and shall set forth the terms and conditions of its tenancy. Nothing
contained in this paragraph shall be construed to impair or modify any right
otherwise exercisable by the Landlord, whether under the Lease or any other
agreement.
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         4.  The Landlord shall not be responsible for any delays incurred by
Tenant in delivering possession of the Sublease Premises to Subtenant as a
result of any matter whatsoever.

         5.  Nothing herein contained shall be deemed a modification or waiver
of any of the Landlord's rights under the Lease, including, without limitation,
the Landlord's right to rental and other monetary consideration payable under
the Sublease in excess of the Rent payable by Tenant under the Lease.

         6.  Neither the Subtenant nor Tenant shall make any additions,
alterations or structural changes in or to the Premises, or any portion thereof,
having a cost of $10,000 or more, without both Tenant and the Subtenant first
obtaining the Landlord's written consent thereto in each instance.

         7.  This Consent to this Sublease is not consent to the construction,
improvements and alterations contemplated by the Sublease. Each such
construction, improvement and alteration requiring consent from the Landlord
must be separately submitted to and approved by Landlord in writing as provided
in the Lease. No roof penetration shall be permitted, without the prior written
consent of Tenant and Landlord, such consent not to be unreasonably withheld.

         8.  Intentionally deleted.

         9.  Except as otherwise specifically permitted under the Sublease, no
amendment, modification or revision of the Sublease shall hereafter be made
without the prior written consent of Landlord.

         10. Tenant and Subtenant hereby represent to Landlord that the Sublease
attached hereto as Exhibit "A" (a) is a correct and complete copy of the
document it purports to be, and (b) contains the entire agreement and
understanding between Tenant and Subtenant with regard to the subject matter
contained thereof, specifically including without limitation, all agreements
concerning rent and other considerations payable by Subtenant to Tenant for the
Premises.

         11. Tenant and Subtenant hereby jointly and severally agree to
indemnify, defend (if requested by Landlord) and hold harmless, Landlord, the
managing agent of the building and their respective officers, directors,
employees, agents and beneficiaries from and against any and all liabilities and
claims for brokerage commissions and fees arising out of or in connection with
the Sublease.

         12. This Agreement shall be binding upon and inure to the benefit of
Landlord, Tenant, Subtenant and their respective successors and permitted
assigns.

         13. This Consent to Sublease shall be deemed limited solely to this
Sublease and shall not relieve Tenant or Subtenant from the obligation to obtain
the consent of

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Landlord to (i) any further Sublease or Sub-sublease Premises, or any part
thereof or any other area covered by the Lease, or (ii) any assignment of the
interest of Tenant under the Lease, or (iii) except as otherwise provided in the
Sublease, any assignment of the interest of the Subtenant under the Sublease.

         14. The consent hereto by Landlord shall not serve as an admission or
assumption of any liability by Landlord to Subtenant or as a representation,
warranty or surety as to any representation or undertakings of the Tenant under
the Sublease.

         15. Subtenant shall obtain and keep in full force and effect during the
term of the Sublease the types and amounts of insurance as are set forth in the
Sublease, and to name the Landlord and any mortgagee of Landlord as additional
insureds. The insurance to be carried by Subtenant shall be in addition to and
separate from the insurance carried by Tenant. A duplicate original insurance
policy or appropriate certificate evidencing the aforesaid insurance coverage
(and each renewal and replacement thereto) shall be delivered to Landlord.

         16. Tenant shall pay to Landlord Seven Hundred Fifty Dollars ($750.00)
to reimburse Landlord's attorney fees and costs in reviewing the Sublease and
preparing this Consent to Sublease.

         17. Landlord hereby agrees to deliver to Subtenant, at the address set
forth below, and simultaneously with its delivery to Tenant, any and all notices
of default by Tenant under the Lease. The failure of Landlord to deliver such
notice to Subtenant shall in no way render ineffective or invalidate any notice
of default given to Tenant pursuant to the Lease.

         Subtenant:        Insmed Incorporated
                           800 East Leigh Street, Suite 206
                           Richmond, Virginia 23219

Dated as of this 12th day of April, 2001.

LANDLORD

BY:  ___________________________

ITS: ___________________________

TENANT                                               SUBTENANT

BY:  ___________________________            BY:  _________________________

ITS: ___________________________            ITS: _________________________

                                       3<PAGE>

                                                                    Exhibit 4.12

                              CERTIFICATE OF TRUST
                                       OF
                               CSX CAPITAL TRUST I

       THIS CERTIFICATE OF TRUST of CSX Capital Trust I (the "Trust"), is being
duly executed and filed by the undersigned, as trustee, to form a business trust
under the Delaware Business Trust Act (12 Del. C. (S)3801, et seq.).

       I.     Name. The name of the business trust formed hereby is CSX Capital
              ----
              Trust I.

       II.    Delaware Trustee. The name and business address of the trustee of
              ----------------
              the Trust with a principal place of business in the State of
              Delaware is Chase Manhattan Bank USA, National Association, 1201
              Market Street, Wilmington, Delaware 19801.

       IN WITNESS WHEREOF, the undersigned trustee of the Trust has executed
this Certificate of Trust in accordance with Section 3811 of the Delaware
Business Trust Act.

                 CHASE MANHATTAN BANK USA, NATIONAL ASSOCIATION
                                            not in its individual capacity
                                            but solely as trustee of the Trust

                                            By: /s/ John J. Cashin
                                                --------------------------------
                                                Name: John J. Cashin
                                                Title: Vice President<PAGE>

                                                                    Exhibit 4.13

                                 TRUST AGREEMENT
                                       OF
                               CSX CAPITAL TRUST I

       THIS TRUST AGREEMENT is made as of May 1, 2001 (this "Trust Agreement"),
by and between CSX Corporation, a Virginia corporation, as sponsor (the
"Sponsor"), and Chase Manhattan Bank USA, National Association, a national
banking association (the "Trustee"). The Sponsor and the Trustee hereby agree as
follows:

       1. The trust created hereby shall be known as "CSX Capital Trust I" (the
"Trust") in which name the Trustee or the Sponsor, to the extent provided
herein, may conduct the business of the Trust, make and execute contracts, and
sue and be sued.

       2. The Sponsor hereby assigns, transfers, conveys and sets over to the
Trust the sum of ten dollars ($10.00). Such amount shall constitute the initial
trust estate. It is the intention of the parties hereto that the Trust created
hereby constitute a business trust under Chapter 38 of Title 12 of the Delaware
Code, 12 Del. C. (S) 3801, et seq. (the "Business Trust Act"), and that this
document constitute the governing instrument of the Trust. The Trustee is hereby
authorized and directed to execute and file a certificate of trust with the
Delaware Secretary of State in accordance with the provisions of the Business
Trust Act.

       3. The Sponsor and the Trustee will enter into an amended and restated
Trust Agreement or Declaration satisfactory to each such party to provide for
the contemplated operation of the Trust created hereby and the issuance of the
Preferred Securities and the Common Securities referred to therein. Prior to the
execution and delivery of such amended and restated Trust Agreement or
Declaration, the Trustee shall not have any duty or obligation hereunder or with
respect of the trust estate, except as otherwise required by applicable law or
as may be necessary to obtain prior to such execution and delivery any licenses,
consents or approvals required by applicable law or otherwise. Notwithstanding
the foregoing, the Trustee may take all actions deemed proper as are necessary
to effect the transactions contemplated herein.

       4. The Sponsor, as the agent of the Trust, is hereby authorized, in its
discretion, (i) to prepare and file with the Securities and Exchange Commission
(the "Commission") and to execute, in each case on behalf of the Trust, (a) a
Registration Statement (the "1933 Act Registration Statement"), including all
pre-effective and post-effective amendments thereto and any related registration
statements filed pursuant to Rule 462(b) under the Securities Act of 1933, as
amended (the "1933 Act"), relating to the registration under the 1933 Act of the
Preferred Securities of the Trust and (b) a Registration Statement on Form 8-A
(the "1934 Act Registration Statement"), including all pre-effective and
post-effective amendments thereto, relating to the registration of the Preferred
Securities of the Trust under the Securities Exchange Act of 1934, as amended;
(ii) if and at such time as determined by the Sponsor, to file with the
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New York Stock Exchange or any other exchange or the National Association of
Securities Dealers (each, an "Exchange"), and execute on behalf of the Trust one
or more listing applications and all other applications, statements,
certificates, agreements and other instruments as shall be necessary or
desirable to cause the Preferred Securities of the Trust to be listed on any of
the Exchanges; (iii) to negotiate, execute, deliver and perform on behalf of the
Trust an underwriting agreement with one or more underwriters relating to the
offering of the Preferred Securities of the Trust; and (iv) to file and execute
on behalf of the Trust, such applications, reports, surety bonds, irrevocable
consents, appointments of attorney for service of process and other papers and
documents that shall be necessary or desirable to register the Preferred
Securities of the Trust under the securities or "Blue Sky" laws of such
jurisdictions as the Sponsor, on behalf of the Trust, may deem necessary or
desirable.

       5. (a) The Trustee (the "Fiduciary Indemnified Person") shall not be
liable, responsible or accountable in damages or otherwise to the Trust, the
Sponsor any holder of the Trust securities (the Trust, the Sponsor and any
holder of the Trust securities being a "Covered Person") for any loss, damage or
claim incurred by reason of any act or omission performed or omitted by the
Fiduciary Indemnified Person in good faith on behalf of the Trust and in a
manner the Fiduciary Indemnified Person reasonably believed to be within the
scope of authority conferred on the Fiduciary Indemnified Person by this
Agreement or by law, except that the Fiduciary Indemnified Person shall be
liable for any such loss, damage or claim incurred by reason of the Fiduciary
Indemnified Person's negligence or willful misconduct with respect to such acts
or omissions.

          (b) The Fiduciary Indemnified Person shall be fully protected in
relying in good faith upon the records of the Trust and upon such information,
opinions, reports or statements presented to the Trust by any person as to
matters the Fiduciary Indemnified Person reasonably believes are within such
other person's professional or expert competence and who has been selected with
reasonable care by or on behalf of the Trust, including information, opinions,
reports or statements as to the value and amount of the assets, liabilities,
profits, losses, or any other facts pertinent to the existence and amount of
assets from which distributions to holders of Trust securities might properly be
paid.

       6. The Sponsor agrees to the fullest extent permitted by applicable law,

          (a) to indemnify and hold harmless the Fiduciary Indemnified Person,
or any of its officers, directors, shareholders, employees, representatives or
agents, from and against any loss, damage, liability, tax, penalty, expense or
claim of any kind or nature whatsoever incurred by the Fiduciary Indemnified
Person by reason of the creation, operation or termination of the Trust in a
manner the Fiduciary Indemnified Person reasonably believed to be within the
scope of authority conferred on the Fiduciary Indemnified Person by this Trust
Agreement, except that the Fiduciary Indemnified Person shall be entitled to be
indemnified in respect of any loss, damage or claim incurred by the Fiduciary
Indemnified Person by reason of negligence or willful misconduct with respect to
such acts or omissions; and

          (b) to advance expenses (including legal fees) incurred by the
Fiduciary Indemnified Person in defending any claim, demand, action, suit or
proceeding, from time to time, prior to the final disposition of such claim,
demand, action, suit or proceeding, upon receipt

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by the Trust of an undertaking by or on behalf of the Fiduciary Indemnified
Person to repay such amount if it shall be determined that the Fiduciary
Indemnified Person is not entitled to be indemnified as authorized in the
preceding subsection.

       7. The provisions of Section 6 shall survive the termination of this
Trust Agreement or the earlier resignation or removal of the Fiduciary
Indemnified Person.

       8. The Trust may be terminated without issuing any Trust securities at
the election of the Sponsor.

       9. This Trust Agreement may be executed in one or more counterparts each
of which shall be deemed an original, but all of which together shall constitute
one and the same instrument.

       10. The number of trustees of the Trust initially shall be one and
thereafter the number of trustees of the Trust shall be such number as shall be
fixed from time to time by a written instrument signed by the Sponsor which may
increase or decrease the number of trustees of the Trust; provided, however,
that to the extent required by the Business Trust Act, one trustee of the Trust
shall either be a natural person who is a resident of the State of Delaware or,
if not a natural person, an entity which has its principal place of business in
the State of Delaware. Subject to the foregoing, the Sponsor is entitled to
appoint or remove without cause any trustee of the Trust at any time. Any
trustee of the Trust may resign upon thirty days' prior notice to the Sponsor.

       11. This Trust Agreement shall be governed by, and construed in
accordance with, the laws of the State of Delaware (without regard to conflict
of laws principles).

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

                       CSX CORPORATION,
                         as Sponsor

                       By: /s/ David H. Baggs
                           -----------------------------------------------
                           Name: David H. Baggs
                           Title: Assistant Vice President - Corporate Treasury

                       CHASE MANHATTAN BANK USA,
                       NATIONAL ASSOCIATION
                       not in its individual capacity but
                       solely as trustee of the Trust

                       By: /s/ John J. Cashin
                           -----------------------------------------------
                              Name: John J. Cashin
                              Title: Vice President

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