Exhibit 4.8

     THE ISSUANCE OF THIS  WARRANT AND ANY SHARES OF COMMON STOCK  ISSUABLE
UPON THE EXERCISE HEREOF HAVE NOT BEEN REGISTERED  UNDER THE SECURITIES ACT
OF 1933, AS AMENDED. ACCORDINGLY, NO TRANSFER OF THIS WARRANT OR ANY SHARES
OF COMMON  STOCK  ISSUABLE OR ISSUED UPON THE  EXERCISE  HEREOF MAY BE MADE
EXCEPT  IN  COMPLIANCE  WITH  SUCH  STATUTE  AND THE  TERMS OF THE  WARRANT
AGREEMENT  REFERRED  TO BELOW,  A COPY OF WHICH IS ON FILE AT THE OFFICE OF
GCA CORPORATION.

Void After 4:00 P.M., Boston Time, on September 1, 2002

                          GCA Corporation Warrant

Number -14-                                Warrant to Purchase 500,000
                                           Shares of Common Stock



     This is to certify that Carl Zeiss,  Inc., or registered  assigns (the
"Holder"),  is  entitled  to  purchase  from GCA  Corporation,  a  Delaware
corporation (the "Company"),  at an exercise price (the "Warrant Price") of
$12.32 per share, at any time prior to 4:00 p.m. (Boston time) on September
1, 2002,  500,000  fully paid and  non-assessable  shares of the  Company's
common  stock,  par value $.01 per share (the "Common  Stock"),  subject to
adjustment as hereinafter provided.

     1. The rights  represented  by this  Warrant may be  exercised  by the
Holder  hereof at any time or from time to time prior to 4:00 p.m.  (Boston
time) on  September  1, 2002,  as to the whole or any part of the shares of
Common Stock covered  hereby,  by the  surrender of this Warrant,  together
with (i) the Subscription Form attached hereto appropriately completed, and
(ii) payment (in cash, by certified check or by wire transfer, in each case
of  immediately  available  funds)  of the  Warrant  Price for the share or
shares of Common  Stock so  purchased,  to the  Company  at its office at 7
Shattuck Road, Andover, Massachusetts 01810 (or at such other office as the
Company may designate by written notice to the holder  hereof).  Thereupon,
this  Warrant  shall  be  deemed  to have  been  exercised  and the  person
exercising  the same  shall be deemed to have  become a holder of record of
the  shares of Common  Stock  purchased  hereunder  for all  purposes,  and
certificates  for  such  shares  of  Common  Stock  so  purchased  shall be
delivered  to the  purchaser  within a  reasonable  time after this Warrant
shall have been exercised as set forth  hereinabove.  If this Warrant shall
be  exercised  in  respect  of only a part of the  shares of  Common  Stock
subject  hereto,  the  Company  shall  deliver  to  the  Holder  a  Warrant
registered in the name of the Holder (or his designee) with respect to that
number of shares of Common Stock in respect of which this Warrant shall not
have been exercised.

     2. No  certificate  for a fraction of a share of Common  Stock will be
issued. As to any fractions of a share of Common Stock that would otherwise
be purchasable on exercise of a Warrant,  the Company shall make payment in
lieu  thereof  in an  amount  of cash  equal to the  current  value of such
fraction  computed on the basis of the last  reported sale price on the day
upon which the  exercise of the Warrant  shall have taken place or, in case
no such  reported  sale takes  place on such day,  the  average of the last
reported bid and asked prices on such day, in either case on the  principal
national securities  exchange (which, for purposes hereof,  shall be deemed
to include the NASDAQ  National Market System) on which the Common Stock is
listed or admitted  to trading,  or if not listed or admitted to trading on
any  national  securities  exchange,  the average mean of the bid and asked
prices  in  the  over-the-counter   market  as  reported  by  the  National
Association of Securities  Dealers  Automated  Quotation System, or if such
organization  is not in existence,  by an  organization  providing  similar
services.

     3. Subject to the terms and conditions of the Warrant Agreement,  this
Warrant and any interest  therein or in the shares of Common Stock issuable
upon exercise  thereof is  transferable  on the books of the Company at its
offices at 7 Shattuck  Road,  Andover,  Massachusetts  01810 (or such other
office as the  Company  may  designate  by  written  notice  to the  holder
hereof),  by the Holder  hereof in person or by duly  authorized  attorney,
upon surrender of this Warrant  together with the Assignment  Form attached
hereto, duly executed,  whereupon this Warrant (and any interest therein or
in the shares of Common  Stock  issuable  upon  exercise  hereof)  shall be
deemed to have been  transferred  and the  transferee  to have  become  the
holder of record thereof.  Promptly  following such surrender,  the Company
shall issue a new Warrant (or certificate of shares) registered in the name
of the transferee.

     4. The  rights of the Holder of this  Warrant  shall be subject to the
following further terms and conditions:

          (a) The  Warrant  Price and the number of shares of Common  Stock
purchasable pursuant to this Warrant shall be subject to adjustment from to
time as follows. In case the Company shall (i) declare a dividend or make a
distribution  on shares of its  Common  Stock  payable  in shares of Common
Stock,  or (ii)  subdivide or reclassify its  outstanding  shares of Common
Stock into a greater  number of shares of Common  Stock (a "stock  split"),
the Warrant Price shall be adjusted by  multiplying  it by a fraction,  (A)
the  numerator  of which  shall be the  number of  shares  of Common  Stock
outstanding  immediately  prior to such stock dividend or stock split,  and
(B) and the  denominator  of which  shall be the number of shares of Common
Stock outstanding  immediately following such stock dividend or stock split
and the number of shares of Common Stock  purchasable  upon the exercise of
this Warrant  immediately  prior thereto shall be multiplied by the inverse
of such fraction. Conversely, in case of any combination,  reclassification
or consolidation of the number of outstanding shares of Common Stock into a
lesser number of shares, the Warrant Price shall be adjusted by multiplying
it by a fraction,  (x) the numerator of which shall be the number of shares
of  Common  Stock  outstanding   immediately  prior  to  such  combination,
reclassification  or consolidation,  and (y) the denominator of which shall
be the number of shares of Common Stock outstanding  immediately  following
such  combination,  reclassification  or  consolidation  and the  number of
shares  of Common  Stock  purchasable  upon the  exercise  of this  Warrant
immediately  prior  thereto  shall be  multiplied  by the  inverse  of such
fraction.  Such adjustments shall be made  successively  whenever any event
listed above shall occur.

          (b) in case of any  reclassification or change in the outstanding
shares of Common Stock (other than a change in par value, or from par value
to no par  value,  or from no par value to par  value,  or as a result of a
subdivision  or  combination,  but  including  any  change of the shares of
Common  Stock into two or more  classes or series of common  stock),  or in
case of any  consolidation  of the Company  with,  or merger of the Company
with or into, another Person (other than a consolidation or merger in which
the  Company  is the  continuing  entity  and which  does not result in any
reclassification  or change in the outstanding  shares of Common Stock), or
in case of any  conveyance or transfer to another Person of the property of
the Company as an entirety or substantially as an entirety, the Company, or
such  successor  purchasing  Person,  shall provide that the Holder of this
Warrant shall have the right to obtain, upon the same terms and conditions,
the kind and amount of shares and other securities,  cash and property that
would  have been  receivable  by such  Holder  upon such  reclassification,
change,  consolidation,  merger,  conveyance  or  transfer  if  the  rights
represented  by such Warrant had been  exercised  to purchase  Common Stock
immediately  prior thereto.  Such other Person,  which shall  thereafter be
deemed to be the Company for purposes of this  Warrant,  shall  provide for
adjustments  which shall be as nearly  equivalent as may be  practicable to
the adjustments provided for hereinabove.

          (c) In case at any time the Company shall propose

               (i) to declare  any  dividend  or make any  distribution  on
shares of Common  Stock  payable in shares of Common  Stock or fix a record
date for the making of any other distribution  (other than a cash dividend)
to all holders of shares of Common Stock; or

               (ii) to fix a record  date for the  issuance  of  rights  or
warrants to all holders of its Common Stock  entitling them to purchase any
additional  shares or beneficial  interest of any class or any other rights
or warrants; or

               (iii) to  consolidate  or merge  with or into any  Person or
convey or transfer its properties and assets  substantially  as an entirety
to any Person; or

               (iv)  to  effect   any   reorganization,   reclassification,
liquidation, dissolution, or winding-up of the Company;

then,  in any one or more of such  cases,  the  Company  shall give 30 days
prior written notice to the Holder of this Warrant of the date on which (A)
the books of the Company  shall  close or a record  shall be taken for such
dividend on shares of Common Stock,  distribution  or offering of rights or
warrants,  or  (B)  such  consolidation,   merger,  conveyance,   transfer,
reorganization,  reclassification,  liquidation,  dissolution or winding-up
shall take place, as the case may be.

          (d) As used in this paragraph 4,

               (i)  "Common  Stock"  shall  mean  the  Common  Stock of the
Company  as  constituted  on the date  hereof,  and  shares of any class or
classes resulting from any reclassification thereof that have no preference
in respect of dividends or amounts payable in the event of any voluntary or
involuntary liquidation, dissolution or winding-up of the Company and which
are not subject to redemption by the Company;

               (ii)  "Persons"  shall  mean  any  individual,  corporation,
partnership,  joint  venture,  association,   joint-stock  company,  trust,
unincorporated  organization  or  government  or any  agency  or  political
subdivision thereof.

          (e) Except as otherwise  provided herein, the Holder hereof shall
not be  entitled  on  account of  holding  this  Warrant to any rights of a
stockholder of the Company either at law or in equity,  or to any notice of
meetings of stockholders or of any other proceedings of the Company.

          (f) The Holder of this Warrant  shall,  upon demand,  disclose to
the Company in writing  such  information  as is readily  available  to the
Holder  with  respect  to  direct,  indirect,  actual  and/or  constructive
ownership of shares of Common Stock and/or Warrants as the Company may deem
necessary to comply with the  provisions  of the  Internal  Revenue Code of
1986 (the "Code") or with the  requirements of any other taxing  authority.
For the purpose of this subparagraph  (f),  "ownership" of shares of Common
Stock  shall be  determined  as  provided in Section 544 of the Code or any
successor  provisions  as then in effect and the number of shares of Common
Stock  owned  shall  include  all  shares of Common  Stock that may then be
acquired  upon  conversion,  exchange  or  exercise  of rights  under other
securities.

          (g) Each Holder of this  Warrant  shall  furnish the Company with
the  address to which all notices  provided  for herein to be given to such
holder  shall be sent.  The Company  shall be entitled  for all purposes to
consider  the  Person in whose  name this  Warrant  is issued as the lawful
owner of this Warrant and is entitled to exercise all his rights hereunder,
and no other Person shall have any rights with respect thereto.




Dated:  September 1, 1987           GCA CORPORATION

                                    By
                                      -------------------------------
                                             (Name and Title)

<PAGE>

                       ASSIGNMENT FORM TO BE EXECUTED
                          UPON TRANSFER OR WARRANT



          FOR VALUE  RECEIVED,  ___________________________________  hereby
sell(s), assign(s) and transfer(s) unto _________________ _________________
the right to purchase  _______ shares of Common Stock covered by the within
Warrant, and do hereby irrevocably constitute and appoint said Attorney, to
transfer  said  right on the books of GCA  Corporation,  with full power of
substitution in the premises.



Dated:                               [                                  ]
      -----------------------         ----------------------------------
                                     By:
                                        --------------------------------
                                     Title:
                                           -----------------------------




<PAGE>

                      SUBSCRIPTION FORM TO BE EXECUTED
                          UPON EXERCISE OR WARRANT



          The  undersigned  hereby  exercises,  according  to the terms and
conditions  thereof,  the right to  purchase  ___________  shares of Common
Stock  evidenced by the within  Warrant;  and herewith makes payment of the
purchase price in full.



Dated:                               [                                  ]
      -----------------------         ----------------------------------
                                     By:
                                        --------------------------------
                                     Title:
                                           -----------------------------