content: <PAGE>   1
  
        As filed with the Securities and Exchange Commission on May 14, 1996
  
                                                              Registration No.
  
  ================================================================================
                         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 or other jurisdiction                 (IRS Employer
           of incorporation or organization)            Identification No.)
  
                                   75 STATE STREET
                             BOSTON, MASSACHUSETTS 02109
             (Address of Principal Executive Office, including zip code)
  
                             1996 EQUITY INCENTIVE PLAN
                              (Full title of the Plan)
  
                             CHARLES D. GERLINGER, ESQ.
                                   75 STATE STREET
                             BOSTON, MASSACHUSETTS 02109
                       (Name and address of agent for service)
  
                                   (617) 342-6170
            (Telephone number, including area code, of agent for service)
  
                                  -----------------
                    APPROXIMATE DATE OF PROPOSED PUBLIC OFFERING:
     As soon as practicable after this Registration Statement becomes effective.
  
                                ---------------------
  <TABLE>
                           CALCULATION OF REGISTRATION FEE
  <CAPTION>
  
  ============================================================================================
  SECURITIES       AMOUNT TO      PROPOSED MAXIMUM     PROPOSED MAXIMUM
     TO BE            BE           OFFERING PRICE         AGGREGATE              AMOUNT OF        
  REGISTERED      REGISTERED        PER SHARE(1)       OFFERING PRICE        REGISTRATION FEE
  - --------------------------------------------------------------------------------------------
  <S>               <C>                 <C>                <C>                    <C> 
  Common Stock, 
   par value 
    $1.00           2,800,000           $26.375            $73,850,000            $25,465.52
  (including           Shares(2)
   Preferred
    Stock
   Purchase
    Rights)
  ============================================================================================
  
  <FN>
  - --------
  
  1  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 May 8, 1996.
  
  2  Plus such indeterminate number of additional shares of Common Stock as may be
  required in the event of a stock dividend, reverse stock split or combination of
  shares, recapitalization or other change in the Company's capital stock. Prior
  to the occurrence of certain events, the Preferred Stock Purchase Rights will
  not be evidenced separately from the Common Stock.
  
  </TABLE>
  
  <PAGE>   2
  
                                       PART II
  
  Item 3. Incorporation of Documents by Reference
  
       The following documents filed with the Securities and Exchange Commission
  (the "Commission") are incorporated herein by reference:
  
       (a) The Company's Annual Report on Form 10-K, dated September 30, 1995,
  filed under 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, 1995, filed under Section 13 of the Exchange Act.
  
       (c) The Company's Quarterly Report on Form 10-Q for the quarter ended March
  31, 1996, filed under 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.
  
       All reports and other documents subsequently filed by the Company pursuant
  to Sections 13, 14 or 15(d) of the Exchange Act, prior to the filing of a
  post-effective amendment which indicates that all securities offered hereby have
  been sold or which deregisters all securities 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 4. Description of Securities
  
       The Company's Common Stock is registered under Section 12 of the Exchange
  Act and the Company's Preferred Stock Purchase Rights are registered under
  Section 12 of the Exchange Act. See Item 3(c) regarding the description
  of the Company's Common Stock and the Company's Preferred Stock Purchase Rights.
  
  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 82,980 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 1996 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
  
  
  
  
  
  
  
  
  
  
  
                                       II-1
  <PAGE>   3
  
  
  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 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 7. Exemption from Registration Claimed
  
       Not Applicable.
  
  Item 8. Exhibits
  
       Exhibit
  
       Number
       ------
         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 Coopers & Lybrand, L.L.P.
        24       Power of Attorney.
        28       1996 Equity Incentive Plan.
  
  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.
  
  
  
  
  
  
  
  
  
  
  
                                       II-2
  <PAGE>   4
  
       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, a copy of the registrant's latest annual report to stockholders furnished
  pursuant to and meeting the requirements of Rule 14a-3 or Rule 14c-3 under the
  Exchange Act, unless such person otherwise has received a copy of such report,
  in which case the registrant shall state in the prospectus that it will promptly
  furnish, without charge, a copy of such report on written request of the person.
  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.
  
       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.
  
  
  
  
  
  
  
  
  
  
  
  
  
  
                                       II-3
  <PAGE>   5
  
  
                                     SIGNATURES
  
       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, and the Commonwealth of Massachusetts,
  May 13, 1996.
  
                                                  CABOT CORPORATION
  
                                                  By /s/ Kennett F. Burnes
                                                    -----------------------------
                                                     Kennett F. Burnes
                                                     President
  
  <TABLE>
  
       PURSUANT TO THE REQUIREMENTS OF THE SECURITIES ACT OF 1933, THIS
  REGISTRATION STATEMENT HAS BEEN SIGNED BELOW BY THE FOLLOWING PERSONS IN THE
  CAPACITIES AND ON THE DATE INDICATED.
  <CAPTION>
  
           SIGNATURE                             TITLE                       DATE
           ---------                             -----                       ----
  <S>                                       <C>                              <C>
  PRINCIPAL EXECUTIVE OFFICER
  
       /s/  Samuel W. Bodman                Director and Chairman of         May 13, 1996
  - -----------------------------------       the Board of Directors
         (Samuel W. Bodman)                    
  
  PRINCIPAL FINANCIAL OFFICER
  
       /s/  Kenyon C. Gilson                Executive Vice President and     May 13, 1996
  - -----------------------------------       Chief Financial Officer
          (Kenyon C. Gilson)                     
  
  
  PRINCIPAL ACCOUNTING OFFICER              
  
       /s/  Paul J. Gormisky                Vice President and Controller    May 13, 1996
  - -----------------------------------       
        (Paul J. Gormisky)
  
                  *                         Director                         May 13, 1996
  - -----------------------------------       
          (Jane C. Bradley)
  
       /s/  Kennett F. Burnes               Director                         May 13, 1996
  - -----------------------------------       
         (Kennett F. Burnes)
  
                  *                         Director                         May 13, 1996
  - -----------------------------------       
          (John G.L. Cabot)
  
                  *                         Director                         May 13, 1996
  - -----------------------------------       
        (Arthur L. Goldstein)
  
                  *                         Director                         May 13, 1996
  - -----------------------------------       
       (Robert P. Henderson)
  
                  *                         Director                         May 13, 1996
  - -----------------------------------       
          (Arnold S. Hiatt)
  
  
  </TABLE>
  
  
  
  
  
  
  
  
                                       II-4
  <PAGE>   6
  
  <TABLE>
  
           SIGNATURE                             TITLE                       DATE
           ---------                             -----                       ----
  
  <S>                                       <C>                              <C> 
  
                  *                         Director                         May 13, 1996
  - ---------------------------------
          (John H. McArthur)
  
                  *                         Director                         May 13, 1996
  - ---------------------------------
           (John F. O'Brien)
  
                  *                         Director                         May 13, 1996
  - ---------------------------------
           (David V. Ragone)
  
                  *                         Director                         May 13, 1996
  - ---------------------------------
        (Charles P. Siess, Jr.)
  
                  *                         Director                         May 13, 1996
  - ---------------------------------
          (Morris Tanenbaum)
  
                  *                         Director                         May 13, 1996
  - ---------------------------------
          (Lydia W. Thomas)
  
  
  
  *By   /s/ Charles D. Gerlinger
        --------------------------------                                     May 13, 1996
         Charles D. Gerlinger
         As Attorney-in-Fact**
  
  <FN>
  - -------------
  
  ** By authority of Power of Attorney filed as Exhibit 24 to this Registration Statement
  
  </TABLE>
  
  
  
  
  
  
  
  
  
  
  
                                       II-5
  <PAGE>   7
                                  EXHIBIT INDEX
  
  
  
  EXHIBIT
  NUMBER                                                                  PAGE
  - -------                                                                 ----
  
  5.              Opinion of Robert Rothberg, Vice President and
                  General Counsel.
  
  23.1            Consent of Robert Rothberg is contained in the
                  Opinion filed as Exhibit 5 to this Registration
                  Statement.
  
  23.2            Consent of Coopers & Lybrand, L.L.P.
  
  24.             Power of Attorney.
  
  28.             1996 Equity Incentive Plan.
  
  
  
  
  
  
  
  
  
  
  
  
  
                                       II-6
metadata_documents: [{"type": "S-8", "sequence": "1", "description": "CABOT CORPORATION", "secsgml_size_bytes": 18846}]
metadata_filer: {"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": "333-03683", "film-number": "96563424"}, "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"}}
text: 1
  
        As filed with the Securities and Exchange Commission on May 14, 1996
  
                                                              Registration No.
  
  ================================================================================
                         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 or other jurisdiction                 (IRS Employer
           of incorporation or organization)            Identification No.)
  
                                   75 STATE STREET
                             BOSTON, MASSACHUSETTS 02109
             (Address of Principal Executive Office, including zip code)
  
                             1996 EQUITY INCENTIVE PLAN
                              (Full title of the Plan)
  
                             CHARLES D. GERLINGER, ESQ.
                                   75 STATE STREET
                             BOSTON, MASSACHUSETTS 02109
                       (Name and address of agent for service)
  
                                   (617) 342-6170
            (Telephone number, including area code, of agent for service)
  
                                  -----------------
                    APPROXIMATE DATE OF PROPOSED PUBLIC OFFERING:
     As soon as practicable after this Registration Statement becomes effective.
  
                                ---------------------
  
                           CALCULATION OF REGISTRATION FEE
  ============================================================================================
  SECURITIES       AMOUNT TO      PROPOSED MAXIMUM     PROPOSED MAXIMUM
     TO BE            BE           OFFERING PRICE         AGGREGATE              AMOUNT OF        
  REGISTERED      REGISTERED        PER SHARE(1)       OFFERING PRICE        REGISTRATION FEE
  - --------------------------------------------------------------------------------------------
  Common Stock, 
   par value 
    $1.00           2,800,000           $26.375            $73,850,000            $25,465.52
  (including           Shares(2)
   Preferred
    Stock
   Purchase
    Rights)
  ============================================================================================
  - --------
  
  1  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 May 8, 1996.
  
  2  Plus such indeterminate number of additional shares of Common Stock as may be
  required in the event of a stock dividend, reverse stock split or combination of
  shares, recapitalization or other change in the Company's capital stock. Prior
  to the occurrence of certain events, the Preferred Stock Purchase Rights will
  not be evidenced separately from the Common Stock.
  2
  
                                       PART II
  
  Item 3. Incorporation of Documents by Reference
  
       The following documents filed with the Securities and Exchange Commission
  (the "Commission") are incorporated herein by reference:
  
       (a) The Company's Annual Report on Form 10-K, dated September 30, 1995,
  filed under 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, 1995, filed under Section 13 of the Exchange Act.
  
       (c) The Company's Quarterly Report on Form 10-Q for the quarter ended March
  31, 1996, filed under 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.
  
       All reports and other documents subsequently filed by the Company pursuant
  to Sections 13, 14 or 15(d) of the Exchange Act, prior to the filing of a
  post-effective amendment which indicates that all securities offered hereby have
  been sold or which deregisters all securities 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 4. Description of Securities
  
       The Company's Common Stock is registered under Section 12 of the Exchange
  Act and the Company's Preferred Stock Purchase Rights are registered under
  Section 12 of the Exchange Act. See Item 3(c) regarding the description
  of the Company's Common Stock and the Company's Preferred Stock Purchase Rights.
  
  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 82,980 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 1996 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
  
                                       II-1
  3
  
  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 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 7. Exemption from Registration Claimed
  
       Not Applicable.
  
  Item 8. Exhibits
  
       Exhibit
  
       Number
       ------
         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 Coopers & Lybrand, L.L.P.
        24       Power of Attorney.
        28       1996 Equity Incentive Plan.
  
  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.
  
                                       II-2
  4
  
       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, a copy of the registrant's latest annual report to stockholders furnished
  pursuant to and meeting the requirements of Rule 14a-3 or Rule 14c-3 under the
  Exchange Act, unless such person otherwise has received a copy of such report,
  in which case the registrant shall state in the prospectus that it will promptly
  furnish, without charge, a copy of such report on written request of the person.
  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.
  
       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.
  
                                       II-3
  5
  
                                     SIGNATURES
  
       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, and the Commonwealth of Massachusetts,
  May 13, 1996.
  
                                                  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 BELOW BY THE FOLLOWING PERSONS IN THE
  CAPACITIES AND ON THE DATE INDICATED.
  SIGNATURE                             TITLE                       DATE
           ---------                             -----                       ----
  PRINCIPAL EXECUTIVE OFFICER
  
       /s/  Samuel W. Bodman                Director and Chairman of         May 13, 1996
  - -----------------------------------       the Board of Directors
         (Samuel W. Bodman)                    
  
  PRINCIPAL FINANCIAL OFFICER
  
       /s/  Kenyon C. Gilson                Executive Vice President and     May 13, 1996
  - -----------------------------------       Chief Financial Officer
          (Kenyon C. Gilson)                     
  
  PRINCIPAL ACCOUNTING OFFICER              
  
       /s/  Paul J. Gormisky                Vice President and Controller    May 13, 1996
  - -----------------------------------       
        (Paul J. Gormisky)
  
                  *                         Director                         May 13, 1996
  - -----------------------------------       
          (Jane C. Bradley)
  
       /s/  Kennett F. Burnes               Director                         May 13, 1996
  - -----------------------------------       
         (Kennett F. Burnes)
  
                  *                         Director                         May 13, 1996
  - -----------------------------------       
          (John G.L. Cabot)
  
                  *                         Director                         May 13, 1996
  - -----------------------------------       
        (Arthur L. Goldstein)
  
                  *                         Director                         May 13, 1996
  - -----------------------------------       
       (Robert P. Henderson)
  
                  *                         Director                         May 13, 1996
  - -----------------------------------       
          (Arnold S. Hiatt)
  II-4
  6
  
           SIGNATURE                             TITLE                       DATE
           ---------                             -----                       ----
  *                         Director                         May 13, 1996
  - ---------------------------------
          (John H. McArthur)
  
                  *                         Director                         May 13, 1996
  - ---------------------------------
           (John F. O'Brien)
  
                  *                         Director                         May 13, 1996
  - ---------------------------------
           (David V. Ragone)
  
                  *                         Director                         May 13, 1996
  - ---------------------------------
        (Charles P. Siess, Jr.)
  
                  *                         Director                         May 13, 1996
  - ---------------------------------
          (Morris Tanenbaum)
  
                  *                         Director                         May 13, 1996
  - ---------------------------------
          (Lydia W. Thomas)
  
  *By   /s/ Charles D. Gerlinger
        --------------------------------                                     May 13, 1996
         Charles D. Gerlinger
         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                                                                  PAGE
  - -------                                                                 ----
  
  5.              Opinion of Robert Rothberg, Vice President and
                  General Counsel.
  
  23.1            Consent of Robert Rothberg is contained in the
                  Opinion filed as Exhibit 5 to this Registration
                  Statement.
  
  23.2            Consent of Coopers & Lybrand, L.L.P.
  
  24.             Power of Attorney.
  
  28.             1996 Equity Incentive Plan.
  
                                       II-6