EXHIBIT E


                        LETTERS BETWEEN SAMUEL HEYMAN AND
                                  WILLIAM JOYCE

                                December 18, 2001
                                 January 8, 2002
                                January 22, 2002


                                   [ISP LOGO]
                        INTERNATIONAL SPECIALTY PRODUCTS
            667 MADISON AVENUE, 12TH FLOOR, NEW YORK, NEW YORK 10021

SAMUEL J. HEYMAN
CHAIRMAN OF THE BOARD

                                                             TEL. (212) 821-1601
                                                             FAX: (212) 821-1605

                                                               December 18, 2001

William H. Joyce, Ph.D., Chairman and
Chief Executive Officer
Hercules Incorporated, Hercules Plaza
1313 North Market Street
Wilmington, DE 19898


Dear Bill:

     I am in receipt of your December 11th letter.

     Bill, my colleagues  and I have worked very hard as Hercules  Board members
to provide you and the Board with the soundest business advice that we can. ONLY
AFTER  MONTHS  OF  DISCUSSION  WITH  RESPECT  TO A  CRITICALLY  IMPORTANT  POINT
AFFECTING THE COMPANY'S ENTIRE  RESTRUCTURING  STRATEGY,  WAS I ABLE TO PERSUADE
YOU THAT HERCULES' DEBT CAN IN FACT BE REFINANCED.  Only recently,  I offered to
be helpful to you in connection with the Company's financing efforts and to make
Susan Yoss  available  as well.  Notwithstanding,  on the theory I guess that no
good deed goes unpunished,  I continue to receive these  unproductive  responses
from you.

     I do not intend to waste time on a  point-by-point  rebuttal of your letter
(in which you incorrectly imply, by way of just one example,  that I had earlier
supported  a  valuation  of  BetzDearborn  in the  $1-1.1  billion  range  while
deliberately omitting reference to my July 9th letter which makes clear that the
opposite  was true.  "While  the  report is  limited  of course by the amount of
information  the  author had access to,  and I  CERTAINLY  DO NOT  SUBSCRIBE  TO
EVERYTHING IN IT--VALUATIONS, FOR EXAMPLE (emphasis added)...")

     And I do not understand why you continue to harp on the potential sale to a
financial  buyer of a partial  interest in  BetzDearborn.  Given the fact that a
refinancing on attractive terms is available to us on a straight debt basis, why
sell equity at a discounted price and encumber the  Company's  major asset which
will  only   complicate  a  subsequent  sale  of  our  remaining  share  of  the
BetzDearborn business?

     As to the principal  point in your letter,  I do in fact revise my thinking
when material facts  change--don't you? For example,  while in the first 60 days
of my  service  on the  Board I  indicated  that I was  supportive  of a sale of
BetzDearborn  at certain prices




were you able to achieve them, my conclusion  was based on the unanimous  advice
of the Company's  investment  bankers and management  that the Hercules debt was
not  refinancible.  When in August,  after having done our own analysis into the
strength of the institutional bank and high yield markets and as a result of our
expectations  of  significantly  higher  cost take outs,  I  concluded  that the
Company's debt was in fact  refinancible,  I accordingly urged you and the Board
at the August Board meeting and in a subsequent  Board call in September to take
the "For Sale" signs down and proceed with the refinancing.

     Moreover,  the case for retention of BetzDearborn became even stronger when
we learned at our  October  Board  meeting  that the Company  was  predicting  a
substantial  increase in EBITDA for BetzDearborn in 2002--for which we obviously
would not be paid in a sale now.  Incidentally,  it would  have been  helpful to
have been provided these  projections at an earlier time so that the Board could
have been in a position to evaluate  the  advisability  of  continuing  the sale
process and/or position our negotiations  with GE. In the same vein,  although I
have  asked  for  these on a number  of  occasions,  the  Board has still yet to
receive 5-year  projections for our businesses,  although Goldman Sachs referred
to  10-year  projections  in  their  recent  presentation.  As you  remember,  I
requested  this  information  in my December  6th letter and again it would have
been  helpful  to have been  provided  this data in  connection  with our recent
deliberations.

     Bill,  our  challenge  is not so much  keeping our options  open but rather
making  them  viable  alternatives.  After  months of  discussion,  last  week's
decision  of the Board  and  yourself  to  authorize  Stuart  Shears to have the
investment bankers complete their due diligence, negotiate definitive terms of a
refinancing and take whatever other action necessary to enable the Company to be
in a position  to launch a  refinancing  right after the first of the year is an
excellent first step.

     All the best,

                                             Sincerely,

                                             /s/ Samuel J. Heyman
SJH: kjc


cc:      HERCULES INC. BOARD OF DIRECTORS
         --------------------------------
         John G. Drosdick
         Richard Fairbanks
         Alan R. Hirsig
         Edith E. Holiday
         Robert Kennedy
         Sunil Kumar
         Jeffrey M. Lipton
         Peter McCausland
         Gloria Schaffer
         Paula A. Sneed
         Raymond S. Troubh
         Joe B. Wyatt




                                   [ISP LOGO]
                        INTERNATIONAL SPECIALTY PRODUCTS
            667 MADISON AVENUE, 12TH FLOOR, NEW YORK, NEW YORK 10021

SAMUEL J. HEYMAN
CHAIRMAN OF THE BOARD

                                                             TEL. (212) 821-1601
                                                             FAX: (212) 821-1605

                                                                 January 8, 2002

William H. Joyce, Ph.D., Chairman and
Chief Executive Officer
Hercules Incorporated, Hercules Plaza
1313 North Market Street
Wilmington, DE 19898


Dear Bill:

     I am deeply  concerned about our call last week in which you indicated that
the  Company's  refinancing  plans have been deferred  until its fourth  quarter
financials are completed. This is absolutely contrary to the clear understanding
reached at our December Board meeting, as summarized in my December 18th letter,
as follows:  "...last  week's  decision of the Board and  yourself to  authorize
Stuart  Shears to have the  investment  bankers  complete  their due  diligence,
negotiate  definitive  terms of a  refinancing  and take  whatever  other action
necessary  to enable the  Company to be in a  position  to launch a  refinancing
right after the first of the year...".

     Bill,  the  refinancing  alternative is still the best course for Hercules,
the  hi-yield  market  continues  to be  extremely  receptive  but can be highly
volatile as well, and we ought to promptly take advantage of the  opportunity we
have.  In this  connection,  I am  enclosing a December  17th  article  from the
CHEMICAL  MARKET  REPORTER  which  points to the fact that a "growing  number of
chemicals  companies" are taking advantage of the financing markets to replace a
substantial  portion of their  short-term  bank debt with long-term  debt, as we
have of course recommended for some time now.

     All the best,


                                               /s/ Samuel J. Heyman
SJH: kjc
enclosure

cc:      HERCULES INC. BOARD OF DIRECTORS
         --------------------------------
         John G. Drosdick
         Richard Fairbanks
         Alan R. Hirsig
         Edith E. Holiday
         Robert Kennedy
         Sunil Kumar
         Jeffrey M. Lipton
         Peter McCausland
         Gloria Schaffer
         Paula A. Sneed
         Raymond S. Troubh
         Joe B. Wyatt




                                    December 17, 2001 | CHEMICAL MARKET REPORTER

Chemical Industry Debt Issuance Surges as Banks Turn Up the Heat

Nearly $2 billion in  long-term  debt  issued or in the  pipeline  in  December,
JOSEPH CHANG reports.

PRESSURED BY banks to reduce short-term debt in a hostile operating environment,
a growing number of chemical companies are issuing substantial amounts of
long-term debt in the credit markets. While companies with strong balance sheets
have been able to get good rates on long-term debt, many in the near investment
grade and lower credit categories have been unable to take advantage of record
low interest rates as risk premiums have risen substantially.

     Just in December alone, there has been over $2.1 billion in long-term debt
issued or being offered in the US chemical industry from companies such as
Ferro, International Specialty Products, OM Group, Dow Chemical, Lyondell and
Olin. Through the first three quarters of 2001, US chemical companies have
issued $6.3 billion in debt versus just $3.2 billion for all of 2000, according
to Young & Partners, a New York City-based investment bank.

     While part of the surge in debt issuance is being driven by lower interest
rates, pressure from banks to reduce short-term debt also plays a significant
role.

     "Interest rates are lower, so companies are taking advantage of that, and
in some cases, companies are trying to extend their debt maturities," says
Standard & Poor's chemicals analyst Peter Kelly. "In other cases, it's to take
out some bank debt to release the pressure from the banks and get covenant
relief."

                                    [GRAPHIC]

     "There's a lot of pressure from the banks on companies to reduce their bank
exposure and increase their public market debt," says Moody's Investors Service
chemicals analyst John Rogers. "Companies that see a window of opportunity are
taking it."

     Another factor in the surge of debt issuance is the relentless string of
credit downgrades in the chemical industry (CMR, 12/3/01, page 1). Companies are
seeking to raise funds or refinance sooner rather than later in the face of
further potential credit deterioration.

     Despite historically low US Treasury rates stemming from 11 consecutive
interest rate cuts by the Federal Reserve in less than a year, chemical
companies in the borderline investment-grade category and high yield areas are
seeing interest rates on their new debt issues rise to unusually high levels.




     "Most of the chemical industry is in the area of Baa (Moody's investment
grade) and below, and the spreads (over the Treasury rate) there are unusually
wide right now," Mr. Rogers points out. "Spreads are as high as 400+ basis
points (4 percentage points and higher), where typically you'd be looking at 250
to 300 basis points max. So rates for even a Baa issuer are around 8 to 9
percent, which are a little high on a long-term basis."

     For example, investment-grade issuer Olin Corp. sold $200 million in
10-year senior notes on December 6. While Olin is rated BBB by S&P and Baa3 by
Moody's, the company sold the debt with a 9.125 percent interest rate,
representing a 415 basis point spread over the 10-year Treasury note. Proceeds
are being used to repay existing indebtedness.

     Lyondell Chemical Company, which is rated somewhat below investment grade
at BB- (S&P) and Ba3 (Moody's), sold $393 million of seven-year senior secured
notes at 9.5 percent on December 4. Proceeds are being used to repay around $384
million of the $1 billion Lyondell has in outstanding term loans on its credit
facility.

                                    [GRAPHIC]

     IMC Global Inc., with ratings of BB (S&P) and Ba2 (Moody's), went to the
market in early October to sell $100 million in seven-year senior unsecured
debt. The yield-to-maturity on those notes was 11 percent, notes Moody's Mr.
Rogers.

     On the other end, chemical companies with strong credit ratings have been
able to sell debt on very favorable terms. The Dow Chemical Company, with an A
rating from S&P, sold $500 million in seven-year global notes on December 6 with
an interest rate of 5.75 percent. The spread was just 98 basis points over US
Treasuries.

     "For companies like Dow and DuPont who have strong credit ratings, this is
an opportunistic time to issue debt because the spreads are reasonable," notes
Mr. Rogers. "If you're in the A range or above and are a well known issuer, you
can come to market fairly cheaply."





[HERCULES LOGO]
                                                      Hercules Incorporated
                                                      Hercules Plaza
                                                      1313 North Market Street
                                                      Wilmington, DE 19894-0001
                                    January 22, 2002  (302) 594-6802
                                                      Fax: (302) 594-6800
                                                      Email: wjoyce@herc.com

                                                      William H. Joyce
                                                      Chairman and
                                                      Chief Executive Officer
VIA FACSIMILE: 212-821-1605

Mr. Samuel J. Heyman
Chairman of the Board
International Specialty Products
667 Madison Avenue, 12th floor
New York, NY 10021


Dear Sam:

     I have received your January 8, 2002 letter, which references your earlier
letter of December 18, 2001. It is obvious that you and I have a different
understanding concerning the steps that are being taken to prepare the Company
for a refinancing should the Board select that option from among those
available. In fact, the Company is continuing to explore and refine all of the
options discussed at our last Board meeting. These include significant
negotiations for the sale of BetzDearborn, which appear to be rapidly
approaching conclusion, exploration of joint venture alternatives, and
preparations for a possible refinancing. Our intention is to be as prepared as
we can be to implement any strategic decision that is made by the Board while,
at the same time, trying to avoid undue expenditures. FOR EXAMPLE, IN CONNECTION
WITH THE REFINANCING ALTERNATIVE, WE HAVE EVALUATED DETAILED FINANCING PROPOSALS
FROM VARIOUS INSTITUTIONS AND HAVE SELECTED THE UNDERWRITING GROUP, WITH THE
INAUGURAL MEETING SCHEDULED FOR TOMORROW IN WILMINGTON. WE DO NOT INTEND,
HOWEVER, TO SIGN ANY UNDERWRITING COMMITMENTS UNLESS AND UNTIL THE BOARD CHOOSES
THE REFINANCING ALTERNATIVE. In the interim, I believe we should proceed
diligently to prepare for a refinancing so that we may be poised to finalize
arrangements and complete a financing transaction at the earliest possible time
in the event the Board should choose that alternative.

     With respect to your December 18 letter, you stated that you did not intend
to waste time on a point-to-point rebuttal of my December 11 letter. In keeping
with that spirit, I will not waste time on a point-by-point rebuttal of your
letter and will limit my response to one of the comments contained in your
letter; specifically, your comment in the very first paragraph of your December
18 letter stating, "ONLY AFTER MONTHS OF




Mr. Samuel J. Heyman
January 22, 2002
Page 2


DISCUSSION WITH RESPECT TO A CRITICALLY IMPORTANT POINT AFFECTING THE COMPANY'S
ENTIRE RESTRUCTURING STRATEGY, WAS I ABLE TO PERSUADE YOU THAT HERCULES' DEBT
CAN IN FACT BE REFINANCED". SAM, WE HAVE COVERED THIS ARGUMENT MANY TIMES
BEFORE. I CHANGED MY POSITION BECAUSE THE FACTS CHANGED, NOT BECAUSE YOU
PERSUADED ME THAT YOUR PRIOR POSITION WAS CORRECT. IN FACT, THE COMPANY'S DEBT
CAN NOW BE REFINANCED BECAUSE THE COMPANY'S COST REDUCTION EFFORTS, COMBINED
WITH A MAJOR CHANGE IN THE CREDIT MARKETS, MADE REFINANCING A FEASIBLE
ALTERNATIVE, WHEREAS IT WAS NOT PREVIOUSLY FEASIBLE.

     I will also not attempt to respond on a point-by-point basis to your
December 26 letter and its enclosure. I will, however, state for the record that
I do not believe the Company's analysis is "just plain wrong in some respects as
pointed out by the enclosed", nor that it "makes the most pessimistic
assumptions possible with regard to other areas". Nor do I acknowledge that "the
sales process was handled poorly by my predecessor," or that your
characterizations of his expectations or attitude are correct.

                                               Sincerely,

                                               /s/ William H. Joyce

                                               William H. Joyce

cc: Hercules Board of Directors