================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                  SCHEDULE 14A
                                 (RULE 14A-101)

                            SCHEDULE 14A INFORMATION

PROXY STATEMENT PURSUANT TO SECTION 14(A) OF THE SECURITIES EXCHANGE ACT OF 1934

FILED BY THE REGISTRANT  [ ]

FILED BY A PARTY OTHER THAN THE REGISTRANT  [X]

CHECK THE APPROPRIATE BOX:

[ ]   PRELIMINARY PROXY STATEMENT
[ ]   DEFINITIVE PROXY STATEMENT            [ ]  CONFIDENTIAL, FOR USE OF THE
[ ]   DEFINITIVE ADDITIONAL MATERIALS            COMMISSION ONLY (AS PERMITTED)
[X]   SOLICITING MATERIAL PURSUANT TO            BY RULE 14A-6(E)(2)
      RULE 14A-12

                             HERCULES INCORPORATED
--------------------------------------------------------------------------------
                (NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)


                      INTERNATIONAL SPECIALTY PRODUCTS INC.
--------------------------------------------------------------------------------
    (NAME OF PERSON(S) FILING PROXY STATEMENT, IF OTHER THAN THE REGISTRANT)



PAYMENT OF FILING FEE (CHECK THE APPROPRIATE BOX):

[X]  NO FEE REQUIRED.

[ ] FEE COMPUTED ON TABLE BELOW PER EXCHANGE ACT RULES 14A-6(I)(4) AND 0-11.

      (1)   TITLE OF EACH CLASS OF SECURITIES TO WHICH TRANSACTION APPLIES:
            NOT APPLICABLE

      --------------------------------------------------------------------------
      (2)   AGGREGATE NUMBER OF SECURITIES TO WHICH TRANSACTION APPLIES:  NOT
            APPLICABLE.

      --------------------------------------------------------------------------
      (3)   PER UNIT PRICE OR OTHER UNDERLYING VALUE OF TRANSACTION
            COMPUTED PURSUANT TO EXCHANGE ACT RULE 0-11 (SET FORTH THE
            AMOUNT ON WHICH THE FILING FEE IS CALCULATED AND STATE HOW
            IT WAS DETERMINED): NOT APPLICABLE.

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



      (4)   PROPOSED MAXIMUM AGGREGATE VALUE OF TRANSACTION:  NOT APPLICABLE.

      --------------------------------------------------------------------------
      (5)   TOTAL FEE PAID:  NOT APPLICABLE.

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

[ ]  FEE PAID PREVIOUSLY WITH PRELIMINARY MATERIALS:

[ ]  CHECK BOX IF ANY PART OF THE FEE IS OFFSET AS PROVIDED BY EXCHANGE
     ACT RULE 0-11(A)(2) AND IDENTIFY THE FILING FOR WHICH THE OFFSETTING
     FEE WAS PAID PREVIOUSLY. IDENTIFY THE PREVIOUS FILING BY REGISTRATION
     STATEMENT NUMBER, OR THE FORM OR SCHEDULE AND THE DATE OF ITS FILING.

      (1)       AMOUNT PREVIOUSLY PAID:  NOT APPLICABLE.

      --------------------------------------------------------------------------
      (2)       FORM, SCHEDULE OR REGISTRATION STATEMENT NO.:  NOT APPLICABLE.

      --------------------------------------------------------------------------
      (3)       FILING PARTY:  NOT APPLICABLE.

      --------------------------------------------------------------------------
      (4)       DATE FILED:  NOT APPLICABLE.

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





                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                  SCHEDULE 13D
                    Under the Securities Exchange Act of 1934

                                (Amendment No. 8)

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

                              HERCULES INCORPORATED
                                (Name of Issuer)

COMMON STOCK, $25/48 STATED VALUE PER SHARE                      427056106
       (Title of class of securities)                          (CUSIP number)

                            RICHARD A. WEINBERG, ESQ.
                        C/O ISP MANAGEMENT COMPANY, INC.
                                 1361 ALPS ROAD
                             WAYNE, NEW JERSEY 07470
                                 (973) 628-4000
            (Name, address and telephone number of person authorized
                     to receive notices and communications)

                                 WITH A COPY TO:

                             STEPHEN E. JACOBS, ESQ.
                           WEIL, GOTSHAL & MANGES LLP
                                767 FIFTH AVENUE
                          NEW YORK, NEW YORK 10153-0119
                                 (212) 310-8000

                                 MARCH 12, 2001
             (Date of event which requires filing of this statement)

If the filing person has previously filed a statement on Schedule 13G to report
the acquisition that is the subject of this Schedule 13D, and is filing this
schedule because of ss.ss. 240.13d-1(e), 240.13d-1(f) or 240.13d-(g), check the
following box. [ ]

Note: Schedules filed in paper format shall include a signed original and five
copies of the schedule, including all exhibits. Seess. 240.13d-7 for other
parties to whom copies are to be sent.

* The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter
disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed
to be "filed" for the purposes of Section 18 of the Securities Exchange Act of
1934 (the "Act") or otherwise subject to the liabilities of that section of the
Act but shall be subject to all other provisions of the Act. (However, see the
Notes.)

                         (Continued on following pages)

                               (Page 1 of 7 Pages)


================================================================================

NY2:\1023268\01\54104.0018



-----------------------------------------------------------              --------------------------------------------------------
                                                                                                         
CUSIP No. 427056106                                             13D                                            Page 2 of 7 Pages
-----------------------------------------------------------              --------------------------------------------------------

----------------------    -------------------------------------------------------------------------------------------------------
          1               NAME OF REPORTING PERSON                                ISP OPCO HOLDINGS INC.
                          S.S. OR I.R.S. IDENTIFICATION NO.
                          OF ABOVE PERSON
----------------------    -------------------------------------------------------------------------------------------------------
          2               CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:                                    (a) [ ]
                                                                                                               (b) [X]
----------------------    -------------------------------------------------------------------------------------------------------
          3               SEC USE ONLY
----------------------    -------------------------------------------------------------------------------------------------------
          4               SOURCE OF FUNDS:                                                  OO
----------------------    -------------------------------------------------------------------------------------------------------
          5               CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
                          PURSUANT TO ITEM 2(d) OR 2(e):                                                           [ ]
----------------------    -------------------------------------------------------------------------------------------------------
          6               CITIZENSHIP OR PLACE OF ORGANIZATION:                                              Delaware
----------------------    -------------------------------------------------------------------------------------------------------
                                  7               SOLE VOTING POWER:                                                  0
      NUMBER OF
        SHARES            -------------------     -------------------------------------------------------------------------------
                                  8               SHARED VOTING POWER:                                       10,719,200
     BENEFICIALLY
       OWNED BY           -------------------     -------------------------------------------------------------------------------
                                  9               SOLE DISPOSITIVE POWER:                                             0
         EACH
      REPORTING           -------------------     -------------------------------------------------------------------------------
                                  10              SHARED DISPOSITIVE POWER:                                  10,719,200
     PERSON WITH
----------------------    -------------------------------------------------------------------------------------------------------
         11               AGGREGATE AMOUNT BENEFICIALLY OWNED BY REPORTING PERSON:                           10,719,200
----------------------    -------------------------------------------------------------------------------------------------------
         12               CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES:                         [ ]
----------------------    -------------------------------------------------------------------------------------------------------
         13               PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11):                                           9.98%
----------------------    -------------------------------------------------------------------------------------------------------
         14               TYPE OF REPORTING PERSON:                               CO
----------------------    -------------------------------------------------------------------------------------------------------




-----------------------------------------------------------              --------------------------------------------------------
                                                                                                         
CUSIP No. 427056106                                             13D                                            Page 3 of 7 Pages
-----------------------------------------------------------              --------------------------------------------------------

----------------------    -------------------------------------------------------------------------------------------------------
          1               NAME OF REPORTING PERSON                                ISP INVESTMENTS INC.
                          S.S. OR I.R.S. IDENTIFICATION NO.
                          OF ABOVE PERSON
----------------------    -------------------------------------------------------------------------------------------------------
          2               CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:                                    (a) [ ]
                                                                                                               (b) [X]
----------------------    -------------------------------------------------------------------------------------------------------
          3               SEC USE ONLY
----------------------    -------------------------------------------------------------------------------------------------------
          4               SOURCE OF FUNDS:                                                  WC, OO
----------------------    -------------------------------------------------------------------------------------------------------
          5               CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
                          PURSUANT TO ITEM 2(d) OR 2(e):                                                           [ ]
----------------------    -------------------------------------------------------------------------------------------------------
          6               CITIZENSHIP OR PLACE OF ORGANIZATION:                                              Delaware
----------------------    -------------------------------------------------------------------------------------------------------
                                  7               SOLE VOTING POWER:                                         10,719,200
      NUMBER OF
        SHARES            -------------------     -------------------------------------------------------------------------------
                                  8               SHARED VOTING POWER:                                                0
     BENEFICIALLY
       OWNED BY           -------------------     -------------------------------------------------------------------------------
                                  9               SOLE DISPOSITIVE POWER:                                    10,719,200
         EACH
      REPORTING           -------------------     -------------------------------------------------------------------------------
                                  10              SHARED DISPOSITIVE POWER:                                           0
     PERSON WITH
----------------------    -------------------------------------------------------------------------------------------------------
         11               AGGREGATE AMOUNT BENEFICIALLY OWNED BY REPORTING PERSON:                                 10,719,200
----------------------    -------------------------------------------------------------------------------------------------------
         12               CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES:                        [ ]
----------------------    -------------------------------------------------------------------------------------------------------
         13               PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11):                                           9.98%
----------------------    -------------------------------------------------------------------------------------------------------
         14               TYPE OF REPORTING PERSON:                               CO
----------------------    -------------------------------------------------------------------------------------------------------




-----------------------------------------------------------              --------------------------------------------------------
                                                                                                         
CUSIP No. 427056106                                             13D                                            Page 4 of 7 Pages
-----------------------------------------------------------              --------------------------------------------------------

----------------------    -------------------------------------------------------------------------------------------------------
          1               NAME OF REPORTING PERSON                                INTERNATIONAL SPECIALTY PRODUCTS INC.
                          S.S. OR I.R.S. IDENTIFICATION NO.
                          OF ABOVE PERSON
----------------------    -------------------------------------------------------------------------------------------------------
          2               CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:                                    (a) [ ]
                                                                                                               (b) [X]
----------------------    -------------------------------------------------------------------------------------------------------
          3               SEC USE ONLY
----------------------    -------------------------------------------------------------------------------------------------------
          4               SOURCE OF FUNDS:                                                  OO
----------------------    -------------------------------------------------------------------------------------------------------
          5               CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
                          PURSUANT TO ITEM 2(d) OR 2(e):                                                           [ ]
----------------------    -------------------------------------------------------------------------------------------------------
          6               CITIZENSHIP OR PLACE OF ORGANIZATION:                                              Delaware
----------------------    -------------------------------------------------------------------------------------------------------
                                  7               SOLE VOTING POWER:                                                  0
      NUMBER OF
        SHARES            -------------------     -------------------------------------------------------------------------------
                                  8               SHARED VOTING POWER:                                       10,719,200
     BENEFICIALLY
       OWNED BY           -------------------     -------------------------------------------------------------------------------
                                  9               SOLE DISPOSITIVE POWER:                                             0
         EACH
      REPORTING           -------------------     -------------------------------------------------------------------------------
                                  10              SHARED DISPOSITIVE POWER:                                  10,719,200
     PERSON WITH
----------------------    -------------------------------------------------------------------------------------------------------
         11               AGGREGATE AMOUNT BENEFICIALLY OWNED BY REPORTING PERSON:                           10,719,200
----------------------    -------------------------------------------------------------------------------------------------------
         12               CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES:                         [ ]
----------------------    -------------------------------------------------------------------------------------------------------
         13               PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11):                                           9.98%
----------------------    -------------------------------------------------------------------------------------------------------
         14               TYPE OF REPORTING PERSON:                               CO
----------------------    -------------------------------------------------------------------------------------------------------






                  This Amendment No. 8 ("Amendment No. 8") amends the statement
of beneficial ownership on Schedule 13D ("Schedule 13D") filed on July 24, 2000,
as amended by Amendment No. 1 filed on October 11, 2000, Amendment No. 2 filed
on January 23, 2001, Amendment No. 3 filed on February 7, 2001, Amendment No. 4
filed on February 20, 2001, Amendment No. 5 filed on February 28, 2001,
Amendment No. 6 filed on March 7, 2001, and Amendment No. 7 filed on March 9,
2001, by and on behalf of ISP Opco Holdings Inc. ("ISP Opco"), ISP Investments
Inc. ("ISP Investments"), and International Specialty Products Inc. ("ISP" and
together with ISP Investments and ISP Opco, the "Reporting Persons") with
respect to their ownership of common stock, stated value $25/48 per share
("Common Stock"), of Hercules Incorporated (the "Company"). Capitalized terms
used herein and not defined herein have the meanings ascribed thereto in the
Schedule 13D, as previously amended.

ITEM 4.           PURPOSE OF TRANSACTION

                  On March 12, 2001, Samuel J. Heyman, Chairman of the Board of
ISP, sent the following letter to Mr. Thomas Gossage, Chairman, CEO and
President of the Company:

Mr. Thomas Gossage
Chairman, CEO and President
Hercules Incorporated
Hercules Plaza
1313 North Market Street
Wilmington, Delaware 19894-0001
Dear Tom:

         We have not received a response to our February 7 and March 8 letters
concerning the director election Bylaw matter. I can only assume that this
matter has been referred to your Board for its determination, and from past
experience I must tell you, quite frankly, that I simply have no confidence in
the willingness of the Hercules Board to do the right thing.

         And this brings us to a second point. In reviewing past actions of the
Hercules Board, which in our opinion evidence a clear disregard for the rights
and interests of the Company's shareholders, we simply cannot be sure that a
favorable vote on resolutions currently included in our Preliminary Proxy
Statement will be implemented by your Board without costly and time consuming
delay and even possible litigation. For example, what possible explanation could
there be for the following:


               In 1992, a non-binding proposal to redeem Hercules' then
         existing, 20% threshold poison pill or submit it to a stockholder vote
         was approved by stockholders. Despite this stockholder mandate, the
         Hercules Board never put it to a definitive vote and refused to
         terminate the pill for three years. And then to add insult to injury,
         notwithstanding the 1992 stockholder vote, the Hercules Board
         implemented just this past August, without notice or shareholder
         approval, a new poison pill with a low 10% threshold.

         In view of the above, we have decided to table our other shareholder
proposals in order to focus the proxy contest on the election of our nominees.
As a result, both sides


                                       5


will be able to address for shareholders, in a very direct and clear cut way,
the paramount issue - the Hercules Board's record of corporate stewardship.

                                   Sincerely,

                              /s/ Samuel J. Heyman

                                      * * *

         ISP HAS FILED A PRELIMINARY PROXY STATEMENT WITH THE U.S. SECURITIES
         AND EXCHANGE COMMISSION RELATING TO ISP'S SOLICITATION OF PROXIES FROM
         THE STOCKHOLDERS OF THE COMPANY FOR USE AT THE 2001 ANNUAL MEETING. ISP
         STRONGLY ADVISES ALL HERCULES STOCKHOLDERS TO READ THE FINAL DEFINITIVE
         PROXY STATEMENT WHEN IT IS AVAILABLE BECAUSE IT WILL CONTAIN IMPORTANT
         INFORMATION. WHEN COMPLETED, THE FINAL DEFINITIVE PROXY STATEMENT AND A
         FORM OF PROXY WILL BE MAILED TO ALL HERCULES STOCKHOLDERS AND WILL BE
         AVAILABLE AT NO CHARGE ON THE SEC WEBSITE AT HTTP:\\WWW.SEC.GOV. THE
         PRELIMINARY PROXY STATEMENT, CONTAINING INFORMATION RELATING TO THE
         PARTICIPANTS IN ISP'S PROXY SOLICITATION, IS CURRENTLY AVAILABLE AT NO
         CHARGE ON THE SEC'S WEBSITE.


             [The remainder of this page intentionally left blank.]





                                       6


                                   SIGNATURES

                  After reasonable inquiry and to the best of their knowledge
and belief, the undersigned certify that the information set forth in this
Statement is true, complete and correct.

Dated:   March 12, 2001

                           ISP OPCO HOLDINGS INC.
                           ISP INVESTMENTS INC.
                           INTERNATIONAL SPECIALTY PRODUCTS INC.


                           By:    /s/ Susan B. Yoos
                                  ---------------------------------------------
                                  Susan B. Yoos
                                  Executive Vice President and Treasurer










                                       7