EXHIBIT 3.10

                            CERTIFICATE OF AMENDMENT
                                       OF
                           AMENDED AND RESTATED BYLAWS
                                       OF
                            NANOMETRICS INCORPORATED

The  undersigned,  Vincent  J.  Coates,  hereby  certifies  that he is the  duly
elected,   qualified   and  acting   Chairman  and   Secretary  of   Nanometrics
Incorporated.

The  undersigned  further  certifies  that the  Amended and  Restated  Bylaws of
Nanometrics  Incorporated,  comprised  of  twenty-five  (25)  pages  which  were
ratified by the Board of Directors of Nanometrics  Incorporated  at a meeting of
such Board held on May 31, 1999, were amended by such Board held at a meeting on
August 3, 2000 as follows:

     RESOLVED:  That the fixed  number of  directors  of the  Company  is hereby
     increased from six to seven.

     RESOLVED  FURTHER:  That the proper  officers  of the  Company be, and they
     hereby are,  authorized,  empowered and directed to amend the Bylaws of the
     Corporation to increase the fixed number of directors from six to seven.

Therefore,  by this  Certificate,  the undersigned  hereby amends such Bylaws by
modifying the second sentence of Article III, Section 3.2, to increase the fixed
number of directors from six to seven and restating Article III, Section 3.2, as
follows:

     3.2  NUMBER OF DIRECTORS:  The number of directors of the corporation shall
          be not less than five (5) nor more than seven (7). The exact number of
          directors  shall  be  seven  (7)  until  changed,  within  the  limits
          specified above, by a bylaw amending this Section 3.2, duly adopted by
          the bard of directors or by the shareholders. The indefinite number of
          directors  may be changed,  or a definite  number may be fixed without
          provision for an indefinite number, by a duly adopted amendment to the
          articles  of  incorporation  or by an  amendment  to this  bylaw  duly
          adopted by the vote or written consent of holders of a majority of the
          outstanding  shares  entitled  to  vote;  provided,  however,  that an
          amendment reducing the fixed number or the minimum number of directors
          to a number  less than five (5)  cannot be  adopted  if the votes cast
          against its adoption at a meeting, or the shares not consenting in the
          case of an action by written  consent,  are equal to more than sixteen
          and two-thirds percent (16-2/3%) of the outstanding shares entitled to
          vote  thereon.  No amendment may change the stated  maximum  number of
          authorized directors to a number greater than two (2) times the stated
          minimum number of directors minus one (1).

          No reduction  of the  authorized  number of  directors  shall have the
          effect of removing any director  before that director's term of office
          expires.

IN WITNESS  WHEREOF,  the  undersigned has hereunto set his hand and affixed the
Corporate  Seal  to  this   Certificate   amending  the  Bylaws  of  Nanometrics
Incorporated, which is effective August 3, 2000.


-------------------------------
Vincent J. Coates
Chairman and Secretary