<PAGE>   1

      As filed with the Securities and Exchange Commission on July 6, 1999
                                           Registration No. 333-[        ]

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

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

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

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

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

                                CABOT CORPORATION
             (Exact name of registrant as specified in its charter)

        DELAWARE                                          04-2271897
(State of Incorporation)                    (I.R.S. Employer Identification No.)

                                75 STATE STREET
                              BOSTON, MASSACHUSETTS
                                   02109-1806
          (Address of principal executive offices, including zip code)

                           1999 EQUITY INCENTIVE PLAN
                              (Full title of Plan)

                             Sarah W. Saunders, Esq.
                                 75 State Street
                           Boston, Massachusetts 02109
                     (Name and address of agent for service)

                                 (617) 345-0100
          (Telephone number, including area code, of agent for service)

                             ----------------------
<TABLE>
                                     CALCULATION OF REGISTRATION FEE
<CAPTION>

   Securities          Amount to be          Proposed maximum         Proposed maximum            Amount of
to be registered        registered            offering price      aggregate offering price*    registration fee
                                                per share*
<S>                  <C>                         <C>                    <C>                       <C>
  Common Stock,      3,000,000 shares             23.625                $70,875,000               $19,703.25
$1.00 par value
</TABLE>
*Estimated solely for the purpose of determining the registration fee pursuant
to rule 457(h) on the basis of the average of the high and low prices of Cabot
Corporation's Common Stock, par value $1.00, reported on The New York Stock
Exchange Composite Transactions Index for June 29, 1999.

<PAGE>   2




                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3. INCORPORATION OF DOCUMENTS BY REFERENCE

     Cabot Corporation (the "Company") hereby incorporates by reference into
this registration statement the following documents previously filed with the
Securities and Exchange Commission (the "Commission"):

     (a) The Company's Annual Report on Form 10-K, dated September 30, 1998,
filed pursuant to Section 13 of the Securities Exchange Act of 1934 (the
"Exchange Act").

     (b) The Company's Quarterly Report on Form 10-Q for the quarter ended
December 31, 1998, filed pursuant to Section 13 of the Exchange Act.

     (c) The Company's Quarterly Report on Form 10-Q for the quarter ended March
31, 1999, filed pursuant to Section 13 of the Exchange Act.

     (d) The description of the Company's Common Stock contained in the
Company's Registration Statement on Form 10 filed pursuant to Section 12 of the
Exchange Act and the description of the Company's Preferred Stock Purchase
Rights contained in the Company's Registration Statement on Form 8-A filed
pursuant to Section 12 of the Exchange Act.

     In addition, all reports and other documents filed by the Company pursuant
to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to the filing
of a post-effective amendment that indicates that all securities offered hereby
have been sold or that deregisters all securities then remaining unsold, shall
be deemed incorporated by reference herein and to be part hereof from the date
of the filing of such reports and other documents.

Item 5. INTERESTS OF NAMED EXPERTS AND COUNSEL

     The validity of the shares of Common Stock offered hereby has been passed
upon for the Company by Robert Rothberg, Esq. At the time of rendering his
opinion as to the legality of the Common Stock being registered hereunder, Mr.
Rothberg had a substantial interest in the Company, as defined by the rules of
the Commission, in that the fair market value of the approximately 113,000
shares of Common Stock owned by him exceeds $50,000. It is anticipated that
additional shares will be issued to Mr. Rothberg pursuant to the 1999 Equity
Incentive Plan. Also, at such time Mr. Rothberg was connected with the Company
in that he was Vice President and General Counsel of the Company.

Item 6. INDEMNIFICATION OF DIRECTORS AND OFFICERS

     Article Eighth (j) of the Company's Certificate of Incorporation and
Section 14 of the Company's by-laws provide that the Company shall indemnify any
person who was a party, is a party or is threatened to be made a party to any
threatened, pending or completed action, suit, or proceeding by reason of the
fact that such person is or was a director, officer, employee or agent of the
Company or is or was serving at the request of the Company as a director,
officer, employee or agent of another company or enterprise, including service
as a fiduciary of an employee benefit plan, against expenses (including
attorneys' fees), judgments, fines, penalties and amounts paid in settlement
incurred in connection with such action, suit or proceeding to the extent
permitted from time to time under the Delaware General Corporation Law. Such
indemnification shall be made as authorized in a specific case upon a
determination by the Board of Directors or the stockholders of the Company. The
rights of indemnification are not exclusive of any other rights to which those
seeking indemnification may be entitled and shall continue as to a person who
ceases to be a director, officer, employee or agent. In addition, under Article
Eighth (i) of the Company's Certificate of Incorporation no director or officer
of the Company shall be liable to the Company or its


                                      II-1

<PAGE>   3


stockholders for monetary damages for any breach of fiduciary duty, except to
the extent that Delaware General Corporation Law prohibits the elimination or
limitation of liability of directors or officers for breach of fiduciary duty.

     Section 145 of the Delaware General Corporation Law authorizes the
indemnification of directors, officers, employees and agents of a corporation
against liability incurred by reason of being a director, officer, employee or
agent, and against expenses (including attorneys' fees) in connection with
defending any action seeking to establish liability, in the case of third-party
claims, if such person acted in good faith and in a manner he or she reasonably
believed to be in or not opposed to the best interests of the corporation,
unless a court otherwise determines. Indemnification is also authorized with
respect to any criminal action or proceeding where such person had no reasonable
cause to believe his or her conduct was unlawful.

     The Company's current directors' and officers' insurance policies cover
directors and officers of the Company and its subsidiaries.

Item 8. EXHIBITS

       Exhibit
       Number  Description of Exhibit
       ------  ----------------------
          4    1999 Equity Incentive Plan.
          5    Opinion of Robert Rothberg, Vice President and General Counsel.
         23.1  Consent of Robert Rothberg is contained in his opinion as filed
               as Exhibit 5 to this Registration Statement.
         23.2  Consent of PricewaterhouseCoopers LLP.
         24    Power of Attorney.

Item 9. UNDERTAKINGS

          A. SUBSEQUENT EXCHANGE ACT DOCUMENTS.

          The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act of 1933 (the "1933 Act"),
each filing of the registrant's annual report pursuant to Section 13(a) or
Section 15(d) of the Exchange Act (and, where applicable, each filing of an
employee benefit plan's annual report pursuant to Section 15(d) of the Exchange
Act) that is incorporated by reference in the registration statement shall be
deemed to be a new registration statement relating to the securities offered
therein, and the offering of such securities at that time shall be deemed to be
the initial bona fide offering thereof.

          B. TO TRANSMIT CERTAIN MATERIAL.

          The undersigned registrant hereby undertakes to deliver or cause to be
delivered with the prospectus, to each person to whom the prospectus is sent or
given, the latest annual report to security holders that is incorporated by
reference in the prospectus and furnished pursuant to and meeting the
requirements of Rule 14a-3 or Rule 14c-3 under the Exchange Act; and, where
interim financial information required to be presented by Article 3 of
Regulation S-X are not set forth in the prospectus, the undersigned also
undertakes to deliver, or cause to be delivered, to each person to whom the
prospectus is sent or given, the latest quarterly report that is specifically
incorporated by reference in the prospectus to provide such interim financial
information.


                                      II-2

<PAGE>   4




          C. UNDERTAKING TO UPDATE ANNUALLY.

          The undersigned registrant hereby undertakes: (1) to file during any
period in which offers or sales are made, a post-effective amendment to the
registration statement: (i) to include any prospectus required by Section
10(a)(3) of the 1933 Act; (ii) to reflect in the prospectus any facts or events
arising after the effective date of the registration statement (or the most
recent post-effective amendment thereof) which, individually or in the
aggregate, represent a fundamental change in the information set forth in the
registration statement; and (iii) to include any material information with
respect to the plan of distribution not previously disclosed in the registration
statement or any material change in such information in the registration
statement; (2) that, for the purpose of determining any liability under the 1933
Act, each such post-effective amendment shall be deemed to be a new registration
statement relating to the securities offered therein, and the offering of such
securities shall be deemed to be the initial bona fide offering thereof; and (3)
to remove from registration by means of a post-effective amendment any of the
securities being registered which remain unsold at the termination of the
offering. Provided, however, that if the information required to be included in
a post-effective amendment by clauses (1)(i) and (1)(ii) of this paragraph is
contained in periodic reports filed with or furnished to the Commission by the
registrant pursuant to Section 13 or Section 15(d) of the Exchange Act that are
incorporated by reference in the registration statement, the registrant need not
file a post-effective amendment to provide such information.

          D. INDEMNIFICATION

          Insofar as indemnification for liabilities arising under the 1933 Act
may be permitted to directors, officers and controlling persons of the
registrant pursuant to the foregoing provisions, or otherwise, the registrant
has been advised that in the opinion of the Commission such indemnification is
against public policy as expressed in the 1933 Act and is, therefore,
unenforceable. In the event that a claim for indemnification against such
liabilities (other than the payment by the registrant of expenses incurred or
paid by a director, officer or controlling person of the registrant in the
successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the registrant will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question whether such indemnification by it is against public
policy as expressed in the 1933 Act and will be governed by the final
adjudication of such issue.


                  [Remainder of page intentionally left blank.]


                                      II-3

<PAGE>   5



                                   SIGNATURES


     THE REGISTRANT. Pursuant to the requirements of the Securities Act of 1933,
the registrant certifies that it has reasonable grounds to believe that it meets
all of the requirements for filing on Form S-8 and has duly caused this
registration statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of Boston, Commonwealth of Massachusetts, on July
6, 1999.

                                             CABOT CORPORATION


                                             By:  /s/ Kennett F. Burnes
                                                  ---------------------
                                                  Kennett F. Burnes
                                                  President

     Pursuant to the requirements of the Securities Act of 1933, this
registration statement has been signed by the following persons in the
capacities and on the date indicated.

<TABLE>
<CAPTION>
     SIGNATURES                    TITLE                                   DATE
     ----------                    ----                                    ----
<S>                                <C>                                     <C>
/s/ Samuel W. Bodman               Director, Chairman of the               July 6, 1999
-----------------------------      Board and Chief Executive
     SAMUEL W. BODMAN              Officer (principal executive
                                   officer)


/s/ Kennett F. Burnes              Director and President                  July 6, 1999
-----------------------------
     KENNETT F. BURNES

/s/ Robert L. Culver               Executive Vice President and            July 6, 1999
-----------------------------      Chief Financial Officer
     ROBERT L. CULVER              (principal financial officer)


/s/ William T. Anderson            Controller                              July 6, 1999
-----------------------------      (principal accounting officer)
     WILLIAM T. ANDERSON

              *                    Director                                July 6, 1999
-----------------------------
     JANE C. BRADLEY

              *                    Director                                July 6, 1999
-----------------------------
     JOHN G.L. CABOT

              *                    Director                                July 6, 1999
-----------------------------
     JOHN S. CLARKESON

              *                    Director                                July 6, 1999
-----------------------------
     ARTHUR L. GOLDSTEIN
</TABLE>


                                      II-4

<PAGE>   6


<TABLE>
<CAPTION>
     SIGNATURES                    TITLE                                   DATE
     ----------                    -----                                   ----
<S>                                <C>                                     <C>
              *                    Director                               July 6, 1999
-----------------------------
     ROBERT P. HENDERSON

              *                    Director                               July 6, 1999
-----------------------------
     ARNOLD S. HIATT

              *                    Director                               July 6, 1999
-----------------------------
     GAUTAM S. KAJI

              *                    Director                               July 6, 1999
-----------------------------
     RODERICK C.G. MACLEOD

              *                    Director                               July 6, 1999
-----------------------------
     JOHN H. MCARTHUR

              *                    Director                               July 6, 1999
-----------------------------
     JOHN F. O'BRIEN

              *                    Director                               July 6, 1999
-----------------------------
     DAVID V. RAGONE

              *                    Director                               July 6, 1999
-----------------------------
     CHARLES P. SIESS, JR.

              *                    Director                               July 6, 1999
-----------------------------
     LYDIA W. THOMAS

              *                    Director                               July 6, 1999
-----------------------------
     MARK S. WRIGHTON



*By  /s/ Sarah W. Saunders
     ------------------------
     SARAH W. SAUNDERS
     AS ATTORNEY-IN-FACT
</TABLE>


* By authority of Power of Attorney filed as Exhibit 24 to this Registration
  Statement.


                                      II-5


<PAGE>   7

                                 EXHIBIT INDEX

       Exhibit
       Number  Description of Exhibit
       ------  ----------------------
          4    1999 Equity Incentive Plan.
          5    Opinion of Robert Rothberg, Vice President and General Counsel.
         23.1  Consent of Robert Rothberg is contained in his opinion as filed
               as Exhibit 5 to this Registration Statement.
         23.2  Consent of PricewaterhouseCoopers LLP.
         24    Power of Attorney.
[{"type": "S-8", "sequence": "1", "description": "CABOT CORPORATION", "secsgml_size_bytes": 17610}]
{"company-data": {"conformed-name": "CABOT CORP", "cik": "0000016040", "assigned-sic": "2890", "irs-number": "042271897", "state-of-incorporation": "DE", "fiscal-year-end": "0930"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-82353", "film-number": "99659701"}, "business-address": {"street1": "75 STATE ST", "city": "BOSTON", "state": "MA", "zip": "02109-1806", "phone": "6173450100"}, "mail-address": {"street1": "75 STATE ST", "city": "BOSTON", "state": "MA", "zip": "82109"}, "former-company": {"former-conformed-name": "CABOT GODFREY L INC", "date-changed": "19680418"}}
1

      As filed with the Securities and Exchange Commission on July 6, 1999
                                           Registration No. 333-[        ]

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

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

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

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

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

                                CABOT CORPORATION
             (Exact name of registrant as specified in its charter)

        DELAWARE                                          04-2271897
(State of Incorporation)                    (I.R.S. Employer Identification No.)

                                75 STATE STREET
                              BOSTON, MASSACHUSETTS
                                   02109-1806
          (Address of principal executive offices, including zip code)

                           1999 EQUITY INCENTIVE PLAN
                              (Full title of Plan)

                             Sarah W. Saunders, Esq.
                                 75 State Street
                           Boston, Massachusetts 02109
                     (Name and address of agent for service)

                                 (617) 345-0100
          (Telephone number, including area code, of agent for service)

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

                                     CALCULATION OF REGISTRATION FEE
Securities          Amount to be          Proposed maximum         Proposed maximum            Amount of
to be registered        registered            offering price      aggregate offering price*    registration fee
                                                per share*
Common Stock,      3,000,000 shares             23.625                $70,875,000               $19,703.25
$1.00 par value
*Estimated solely for the purpose of determining the registration fee pursuant
to rule 457(h) on the basis of the average of the high and low prices of Cabot
Corporation's Common Stock, par value $1.00, reported on The New York Stock
Exchange Composite Transactions Index for June 29, 1999.
2

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3. INCORPORATION OF DOCUMENTS BY REFERENCE

     Cabot Corporation (the "Company") hereby incorporates by reference into
this registration statement the following documents previously filed with the
Securities and Exchange Commission (the "Commission"):

     (a) The Company's Annual Report on Form 10-K, dated September 30, 1998,
filed pursuant to Section 13 of the Securities Exchange Act of 1934 (the
"Exchange Act").

     (b) The Company's Quarterly Report on Form 10-Q for the quarter ended
December 31, 1998, filed pursuant to Section 13 of the Exchange Act.

     (c) The Company's Quarterly Report on Form 10-Q for the quarter ended March
31, 1999, filed pursuant to Section 13 of the Exchange Act.

     (d) The description of the Company's Common Stock contained in the
Company's Registration Statement on Form 10 filed pursuant to Section 12 of the
Exchange Act and the description of the Company's Preferred Stock Purchase
Rights contained in the Company's Registration Statement on Form 8-A filed
pursuant to Section 12 of the Exchange Act.

     In addition, all reports and other documents filed by the Company pursuant
to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to the filing
of a post-effective amendment that indicates that all securities offered hereby
have been sold or that deregisters all securities then remaining unsold, shall
be deemed incorporated by reference herein and to be part hereof from the date
of the filing of such reports and other documents.

Item 5. INTERESTS OF NAMED EXPERTS AND COUNSEL

     The validity of the shares of Common Stock offered hereby has been passed
upon for the Company by Robert Rothberg, Esq. At the time of rendering his
opinion as to the legality of the Common Stock being registered hereunder, Mr.
Rothberg had a substantial interest in the Company, as defined by the rules of
the Commission, in that the fair market value of the approximately 113,000
shares of Common Stock owned by him exceeds $50,000. It is anticipated that
additional shares will be issued to Mr. Rothberg pursuant to the 1999 Equity
Incentive Plan. Also, at such time Mr. Rothberg was connected with the Company
in that he was Vice President and General Counsel of the Company.

Item 6. INDEMNIFICATION OF DIRECTORS AND OFFICERS

     Article Eighth (j) of the Company's Certificate of Incorporation and
Section 14 of the Company's by-laws provide that the Company shall indemnify any
person who was a party, is a party or is threatened to be made a party to any
threatened, pending or completed action, suit, or proceeding by reason of the
fact that such person is or was a director, officer, employee or agent of the
Company or is or was serving at the request of the Company as a director,
officer, employee or agent of another company or enterprise, including service
as a fiduciary of an employee benefit plan, against expenses (including
attorneys' fees), judgments, fines, penalties and amounts paid in settlement
incurred in connection with such action, suit or proceeding to the extent
permitted from time to time under the Delaware General Corporation Law. Such
indemnification shall be made as authorized in a specific case upon a
determination by the Board of Directors or the stockholders of the Company. The
rights of indemnification are not exclusive of any other rights to which those
seeking indemnification may be entitled and shall continue as to a person who
ceases to be a director, officer, employee or agent. In addition, under Article
Eighth (i) of the Company's Certificate of Incorporation no director or officer
of the Company shall be liable to the Company or its

                                      II-1
3

stockholders for monetary damages for any breach of fiduciary duty, except to
the extent that Delaware General Corporation Law prohibits the elimination or
limitation of liability of directors or officers for breach of fiduciary duty.

     Section 145 of the Delaware General Corporation Law authorizes the
indemnification of directors, officers, employees and agents of a corporation
against liability incurred by reason of being a director, officer, employee or
agent, and against expenses (including attorneys' fees) in connection with
defending any action seeking to establish liability, in the case of third-party
claims, if such person acted in good faith and in a manner he or she reasonably
believed to be in or not opposed to the best interests of the corporation,
unless a court otherwise determines. Indemnification is also authorized with
respect to any criminal action or proceeding where such person had no reasonable
cause to believe his or her conduct was unlawful.

     The Company's current directors' and officers' insurance policies cover
directors and officers of the Company and its subsidiaries.

Item 8. EXHIBITS

       Exhibit
       Number  Description of Exhibit
       ------  ----------------------
          4    1999 Equity Incentive Plan.
          5    Opinion of Robert Rothberg, Vice President and General Counsel.
         23.1  Consent of Robert Rothberg is contained in his opinion as filed
               as Exhibit 5 to this Registration Statement.
         23.2  Consent of PricewaterhouseCoopers LLP.
         24    Power of Attorney.

Item 9. UNDERTAKINGS

          A. SUBSEQUENT EXCHANGE ACT DOCUMENTS.

          The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act of 1933 (the "1933 Act"),
each filing of the registrant's annual report pursuant to Section 13(a) or
Section 15(d) of the Exchange Act (and, where applicable, each filing of an
employee benefit plan's annual report pursuant to Section 15(d) of the Exchange
Act) that is incorporated by reference in the registration statement shall be
deemed to be a new registration statement relating to the securities offered
therein, and the offering of such securities at that time shall be deemed to be
the initial bona fide offering thereof.

          B. TO TRANSMIT CERTAIN MATERIAL.

          The undersigned registrant hereby undertakes to deliver or cause to be
delivered with the prospectus, to each person to whom the prospectus is sent or
given, the latest annual report to security holders that is incorporated by
reference in the prospectus and furnished pursuant to and meeting the
requirements of Rule 14a-3 or Rule 14c-3 under the Exchange Act; and, where
interim financial information required to be presented by Article 3 of
Regulation S-X are not set forth in the prospectus, the undersigned also
undertakes to deliver, or cause to be delivered, to each person to whom the
prospectus is sent or given, the latest quarterly report that is specifically
incorporated by reference in the prospectus to provide such interim financial
information.

                                      II-2
4

          C. UNDERTAKING TO UPDATE ANNUALLY.

          The undersigned registrant hereby undertakes: (1) to file during any
period in which offers or sales are made, a post-effective amendment to the
registration statement: (i) to include any prospectus required by Section
10(a)(3) of the 1933 Act; (ii) to reflect in the prospectus any facts or events
arising after the effective date of the registration statement (or the most
recent post-effective amendment thereof) which, individually or in the
aggregate, represent a fundamental change in the information set forth in the
registration statement; and (iii) to include any material information with
respect to the plan of distribution not previously disclosed in the registration
statement or any material change in such information in the registration
statement; (2) that, for the purpose of determining any liability under the 1933
Act, each such post-effective amendment shall be deemed to be a new registration
statement relating to the securities offered therein, and the offering of such
securities shall be deemed to be the initial bona fide offering thereof; and (3)
to remove from registration by means of a post-effective amendment any of the
securities being registered which remain unsold at the termination of the
offering. Provided, however, that if the information required to be included in
a post-effective amendment by clauses (1)(i) and (1)(ii) of this paragraph is
contained in periodic reports filed with or furnished to the Commission by the
registrant pursuant to Section 13 or Section 15(d) of the Exchange Act that are
incorporated by reference in the registration statement, the registrant need not
file a post-effective amendment to provide such information.

          D. INDEMNIFICATION

          Insofar as indemnification for liabilities arising under the 1933 Act
may be permitted to directors, officers and controlling persons of the
registrant pursuant to the foregoing provisions, or otherwise, the registrant
has been advised that in the opinion of the Commission such indemnification is
against public policy as expressed in the 1933 Act and is, therefore,
unenforceable. In the event that a claim for indemnification against such
liabilities (other than the payment by the registrant of expenses incurred or
paid by a director, officer or controlling person of the registrant in the
successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the registrant will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question whether such indemnification by it is against public
policy as expressed in the 1933 Act and will be governed by the final
adjudication of such issue.

                  [Remainder of page intentionally left blank.]

                                      II-3
5

                                   SIGNATURES

     THE REGISTRANT. Pursuant to the requirements of the Securities Act of 1933,
the registrant certifies that it has reasonable grounds to believe that it meets
all of the requirements for filing on Form S-8 and has duly caused this
registration statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of Boston, Commonwealth of Massachusetts, on July
6, 1999.

                                             CABOT CORPORATION

                                             By:  /s/ Kennett F. Burnes
                                                  ---------------------
                                                  Kennett F. Burnes
                                                  President

     Pursuant to the requirements of the Securities Act of 1933, this
registration statement has been signed by the following persons in the
capacities and on the date indicated.
SIGNATURES                    TITLE                                   DATE
     ----------                    ----                                    ----
/s/ Samuel W. Bodman               Director, Chairman of the               July 6, 1999
-----------------------------      Board and Chief Executive
     SAMUEL W. BODMAN              Officer (principal executive
                                   officer)

/s/ Kennett F. Burnes              Director and President                  July 6, 1999
-----------------------------
     KENNETT F. BURNES

/s/ Robert L. Culver               Executive Vice President and            July 6, 1999
-----------------------------      Chief Financial Officer
     ROBERT L. CULVER              (principal financial officer)

/s/ William T. Anderson            Controller                              July 6, 1999
-----------------------------      (principal accounting officer)
     WILLIAM T. ANDERSON

              *                    Director                                July 6, 1999
-----------------------------
     JANE C. BRADLEY

              *                    Director                                July 6, 1999
-----------------------------
     JOHN G.L. CABOT

              *                    Director                                July 6, 1999
-----------------------------
     JOHN S. CLARKESON

              *                    Director                                July 6, 1999
-----------------------------
     ARTHUR L. GOLDSTEIN
II-4
6
SIGNATURES                    TITLE                                   DATE
     ----------                    -----                                   ----
*                    Director                               July 6, 1999
-----------------------------
     ROBERT P. HENDERSON

              *                    Director                               July 6, 1999
-----------------------------
     ARNOLD S. HIATT

              *                    Director                               July 6, 1999
-----------------------------
     GAUTAM S. KAJI

              *                    Director                               July 6, 1999
-----------------------------
     RODERICK C.G. MACLEOD

              *                    Director                               July 6, 1999
-----------------------------
     JOHN H. MCARTHUR

              *                    Director                               July 6, 1999
-----------------------------
     JOHN F. O'BRIEN

              *                    Director                               July 6, 1999
-----------------------------
     DAVID V. RAGONE

              *                    Director                               July 6, 1999
-----------------------------
     CHARLES P. SIESS, JR.

              *                    Director                               July 6, 1999
-----------------------------
     LYDIA W. THOMAS

              *                    Director                               July 6, 1999
-----------------------------
     MARK S. WRIGHTON

*By  /s/ Sarah W. Saunders
     ------------------------
     SARAH W. SAUNDERS
     AS ATTORNEY-IN-FACT
* By authority of Power of Attorney filed as Exhibit 24 to this Registration
  Statement.

                                      II-5
7

                                 EXHIBIT INDEX

       Exhibit
       Number  Description of Exhibit
       ------  ----------------------
          4    1999 Equity Incentive Plan.
          5    Opinion of Robert Rothberg, Vice President and General Counsel.
         23.1  Consent of Robert Rothberg is contained in his opinion as filed
               as Exhibit 5 to this Registration Statement.
         23.2  Consent of PricewaterhouseCoopers LLP.
         24    Power of Attorney.