UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                 SCHEDULE 13G/A

                                 AMENDMENT NO. 3

                    UNDER THE SECURITIES EXCHANGE ACT OF 1934

                            MERRIMAC INDUSTRIES, INC.
                                (Name of Issuer)

                          COMMON STOCK, $.01 PAR VALUE
                         (Title of Class of Securities)

                                    590262101
                                 (CUSIP Number)

                                 March 13, 2007
             (Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:

      |_|   Rule 13d-1(b)
      |X|   Rule 13d-1(c)
      |_|   Rule 13d-1(d)

*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 the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("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).



--------------------------------------------------------------------------------
1.   NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NUMBER OF
     ABOVE PERSON

     RICHARD GROSSMAN
--------------------------------------------------------------------------------
2.   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

                                                                 (a)  |X|
                                                                 (b)  |_|
--------------------------------------------------------------------------------
3.   SEC USE ONLY


--------------------------------------------------------------------------------
4.   CITIZENSHIP OR PLACE OF ORGANIZATION

     UNITED STATES
--------------------------------------------------------------------------------
               5.   SOLE VOTING POWER

                    0
  NUMBER OF    -----------------------------------------------------------------
   SHARES      6.   SHARED VOTING POWER
BENEFICIALLY
  OWNED BY          0
    EACH       -----------------------------------------------------------------
  REPORTING    7.   SOLE DISPOSITIVE POWER
   PERSON
    WITH:           0
               -----------------------------------------------------------------
               8.   SHARED DISPOSITIVE POWER

                    0
--------------------------------------------------------------------------------
9.   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON.

     0
--------------------------------------------------------------------------------
10.  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW 9 EXCLUDES CERTAIN SHARES*

                                       |_|
--------------------------------------------------------------------------------
11.  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9.

     0%
--------------------------------------------------------------------------------
12.  TYPE OF REPORTING PERSON*

     IN
--------------------------------------------------------------------------------


                                     - 2 -


--------------------------------------------------------------------------------
1.   NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NUMBER OF
     ABOVE PERSON

     ORIN HIRSCHMAN
--------------------------------------------------------------------------------
2.   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

                                                                 (a)  |X|
                                                                 (b)  |_|
--------------------------------------------------------------------------------
3.   SEC USE ONLY


--------------------------------------------------------------------------------
4.   CITIZENSHIP OR PLACE OF ORGANIZATION

     UNITED STATES
--------------------------------------------------------------------------------
               5.   SOLE VOTING POWER

                    0
  NUMBER OF    -----------------------------------------------------------------
   SHARES      6.   SHARED VOTING POWER
BENEFICIALLY
  OWNED BY          0
    EACH       -----------------------------------------------------------------
  REPORTING    7.   SOLE DISPOSITIVE POWER
   PERSON
    WITH:           0
               -----------------------------------------------------------------
               8.   SHARED DISPOSITIVE POWER

                    0
--------------------------------------------------------------------------------
9.   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON.

     0
--------------------------------------------------------------------------------
10.  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW 9 EXCLUDES CERTAIN SHARES*

                                       |_|
--------------------------------------------------------------------------------
11.  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9.

     0%
--------------------------------------------------------------------------------
12.  TYPE OF REPORTING PERSON*

     IN
--------------------------------------------------------------------------------



                                     - 3 -


--------------------------------------------------------------------------------
1.   NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NUMBER OF
     ABOVE PERSON

     ADAM SMITH CAPITAL MANAGEMENT LLC
--------------------------------------------------------------------------------
2.   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

                                                                 (a)  |X|
                                                                 (b)  |_|
--------------------------------------------------------------------------------
3.   SEC USE ONLY


--------------------------------------------------------------------------------
4.   CITIZENSHIP OR PLACE OF ORGANIZATION

     NEW YORK
--------------------------------------------------------------------------------
               5.   SOLE VOTING POWER

                    0
  NUMBER OF    -----------------------------------------------------------------
   SHARES      6.   SHARED VOTING POWER
BENEFICIALLY
  OWNED BY          0
    EACH       -----------------------------------------------------------------
  REPORTING    7.   SOLE DISPOSITIVE POWER
   PERSON
    WITH:           0
               -----------------------------------------------------------------
               8.   SHARED DISPOSITIVE POWER

                    0
--------------------------------------------------------------------------------
9.   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON.

     0
--------------------------------------------------------------------------------
10.  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW 9 EXCLUDES CERTAIN SHARES*

                                       |_|
--------------------------------------------------------------------------------
11.  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9.

     0%
--------------------------------------------------------------------------------
12.  TYPE OF REPORTING PERSON*

     OO
--------------------------------------------------------------------------------


                                     - 4 -


--------------------------------------------------------------------------------
1.   NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NUMBER OF
     ABOVE PERSON

     ADAM SMITH INVESTMENT PARTNERS, L.P.
--------------------------------------------------------------------------------
2.   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

                                                                 (a)  |X|
                                                                 (b)  |_|
--------------------------------------------------------------------------------
3.   SEC USE ONLY


--------------------------------------------------------------------------------
4.   CITIZENSHIP OR PLACE OF ORGANIZATION

     NEW YORK
--------------------------------------------------------------------------------
               5.   SOLE VOTING POWER

                    0
  NUMBER OF    -----------------------------------------------------------------
   SHARES      6.   SHARED VOTING POWER
BENEFICIALLY
  OWNED BY          0
    EACH       -----------------------------------------------------------------
  REPORTING    7.   SOLE DISPOSITIVE POWER
   PERSON
    WITH:           0
               -----------------------------------------------------------------
               8.   SHARED DISPOSITIVE POWER

                    0
--------------------------------------------------------------------------------
9.   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON.

     0
--------------------------------------------------------------------------------
10.  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW 9 EXCLUDES CERTAIN SHARES*

                                       |_|
--------------------------------------------------------------------------------
11.  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9.

     0%
--------------------------------------------------------------------------------
12.  TYPE OF REPORTING PERSON*

     PN
--------------------------------------------------------------------------------


                                     - 5 -


--------------------------------------------------------------------------------
1.   NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NUMBER OF
     ABOVE PERSON

     DIAMOND CAPITAL MANAGEMENT INC.
--------------------------------------------------------------------------------
2.   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

                                                                 (a)  |X|
                                                                 (b)  |_|
--------------------------------------------------------------------------------
3.   SEC USE ONLY


--------------------------------------------------------------------------------
4.   CITIZENSHIP OR PLACE OF ORGANIZATION

     NEW YORK
--------------------------------------------------------------------------------
               5.   SOLE VOTING POWER

                    0
  NUMBER OF    -----------------------------------------------------------------
   SHARES      6.   SHARED VOTING POWER
BENEFICIALLY
  OWNED BY          0
    EACH       -----------------------------------------------------------------
  REPORTING    7.   SOLE DISPOSITIVE POWER
   PERSON
    WITH:           0
               -----------------------------------------------------------------
               8.   SHARED DISPOSITIVE POWER

                    0
--------------------------------------------------------------------------------
9.   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON.

     0
--------------------------------------------------------------------------------
10.  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW 9 EXCLUDES CERTAIN SHARES*

                                       |_|
--------------------------------------------------------------------------------
11.  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9.

     0%
--------------------------------------------------------------------------------
12.  TYPE OF REPORTING PERSON*

     CO
--------------------------------------------------------------------------------


                                     - 6 -


--------------------------------------------------------------------------------
1.   NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NUMBER OF
     ABOVE PERSON

     ADAM SMITH INVESTMENTS, LTD.
--------------------------------------------------------------------------------
2.   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

                                                                 (a)  |X|
                                                                 (b)  |_|
--------------------------------------------------------------------------------
3.   SEC USE ONLY


--------------------------------------------------------------------------------
4.   CITIZENSHIP OR PLACE OF ORGANIZATION

     BRITISH VIRGIN ISLANDS
--------------------------------------------------------------------------------
               5.   SOLE VOTING POWER

                    0
  NUMBER OF    -----------------------------------------------------------------
   SHARES      6.   SHARED VOTING POWER
BENEFICIALLY
  OWNED BY          0
    EACH       -----------------------------------------------------------------
  REPORTING    7.   SOLE DISPOSITIVE POWER
   PERSON
    WITH:           0
               -----------------------------------------------------------------
               8.   SHARED DISPOSITIVE POWER

                    0
--------------------------------------------------------------------------------
9.   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON.

     0
--------------------------------------------------------------------------------
10.  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW 9 EXCLUDES CERTAIN SHARES*

                                       |_|
--------------------------------------------------------------------------------
11.  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9.

     0%
--------------------------------------------------------------------------------
12.  TYPE OF REPORTING PERSON*

     CO
--------------------------------------------------------------------------------


                                     - 7 -


--------------------------------------------------------------------------------
1.   NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NUMBER OF
     ABOVE PERSON

     RICHARD AND ANA GROSSMAN JTWROS
--------------------------------------------------------------------------------
2.   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

                                                                 (a)  |X|
                                                                 (b)  |_|
--------------------------------------------------------------------------------
3.   SEC USE ONLY


--------------------------------------------------------------------------------
4.   CITIZENSHIP OR PLACE OF ORGANIZATION

     NEW YORK
--------------------------------------------------------------------------------
               5.   SOLE VOTING POWER

                    0
  NUMBER OF    -----------------------------------------------------------------
   SHARES      6.   SHARED VOTING POWER
BENEFICIALLY
  OWNED BY          0
    EACH       -----------------------------------------------------------------
  REPORTING    7.   SOLE DISPOSITIVE POWER
   PERSON
    WITH:           0
               -----------------------------------------------------------------
               8.   SHARED DISPOSITIVE POWER

                    0
--------------------------------------------------------------------------------
9.   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON.

     0
--------------------------------------------------------------------------------
10.  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW 9 EXCLUDES CERTAIN SHARES*

                                       |_|
--------------------------------------------------------------------------------
11.  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9.

     0%
--------------------------------------------------------------------------------
12.  TYPE OF REPORTING PERSON*

     IN
--------------------------------------------------------------------------------


                                     - 8 -


      SCHEDULE 13G

Item 1(a)   Name of Issuer:

            Merrimac Industries, Inc.

Item 1(b)   Address of Issuer's Principal Executive Offices:

            41 Fairfield Place, West Caldwell, New Jersey 07006

Item 2(a)   Names of Persons Filing:

            Richard Grossman, Orin Hirschman, Adam Smith Capital Management LLC
            ("ASCM"), Diamond Capital Management ("DCM"), Adam Smith
            Investments, Ltd. ("ASI"), Adam Smith Investment Partners, L.P.
            ("ASIP"), Richard and Ana Grossman JTWROS.

Item 2(b)   Addresses of Principal Business Offices:

            The principal executive offices of ASCM, ASIP and DCM, and the
            business address of Richard Grossman, are located c/o Richard
            Grossman, 259 Oakford Street, West Hempstead, NY 11552, and Orin
            Hirschman, 6006 Berkeley Ave., Baltimore, MD 21209. The principal
            executive office of ASI is c/o Insinger Trust (BVI) Limited, Tropic
            Isle Building, P.O. Box 438, Road Town, Tortola, British Virgin
            Islands.

Item 2(c)   Citizenship:

            ASCM is a New York limited liability company, DCM is a New York
            corporation, ASI is a British Virgin Islands corporation, and ASIP
            is a New York limited partnership. Richard Grossman, Ana Grossman,
            and Orin Hirschman are citizens of the United States.

Item 2(d)   Title of Class of Securities:

            Common Stock (the "Shares").

Item 2(e)   CUSIP Number:

            590262101

Item 3.     Type of Reporting Person:

            N/A

Item 4.     Ownership

            a.    Amount Beneficially Owned:

                  0 Shares


                                     - 9 -


            b.    Percent of class

                  0%

            c.    Number of shares as to which such person has:

                  i.    Sole power to vote or to direct the vote

                        0

                  ii.   Shared power to vote or to direct the vote

                        0

                  iii.  Sole power to dispose or to direct the disposition of

                        0

                  iv.   Shared power to dispose or to direct the disposition of

                        0

Item 5.     Ownership of Five Percent or Less of a Class:

            If this statement is being filed to report the fact that as of the
            date hereof the reporting person has ceased to be the beneficial
            owner of more than five percent of the class of securities, check
            the following. |X|

Item 6.     Ownership of More than Five Percent on behalf of Another Person.

            N/A

Item 7.     Identification and Classification of the Subsidiary Which Acquired
            the Security Being Reporting on by the Parent Holding Company:

            N/A

Item 8.     Identification and Classification of Members of the Group.

            This Statement is filed by Richard Grossman and Orin Hirschman by
            virtue of their former beneficial ownership of Shares, directly and
            indirectly as the owners of each of ASCM and DCM, and as the sole
            holders of the Common Stock of ASI; by DCM by virtue of being the
            Investment Manager of ASI; by ASCM, by virtue of being the sole
            general partner of ASIP; and by ASI and ASIP by virtue of their
            former direct beneficial ownership of Shares. By virtue of the
            relationships described above, each of Richard Grossman and Orin
            Hirschman may have been formerly deemed to possess indirect
            beneficial ownership of the Shares held by each entity. The
            directors of ASI are F.M.C. Limited and S.C.S. Limited, which are
            subsidiaries of Insinger Trust (BVI) Limited, all of which are
            British Virgin


                                     - 10 -


            Islands corporations. Richard Grossman and Orin Hirschman are the
            only officers and directors of ASC and DCM, and the only
            member-managers of ASCM. This Statement is filed by Richard and Ana
            Grossman JTWROS, by virtue of their former direct beneficial
            ownership of Shares.

Item 9.     Notice of Dissolution of Group:

            N/A

Item 10.    Certification:

            By signing below the undersigned certify that to the best of their
            knowledge and belief, the securities referred to above were not
            acquired and are not held for the purpose of or with the effect of
            changing or influencing the control of the issuer of the securities
            and are not held in connection with or as a participant in any
            transaction having that purpose or effect.

            Signature

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

Date: March 21, 2007

                           /s/ Richard Grossman
                           -----------------------
                           Richard Grossman

                           /s/ Orin Hirschman
                           -----------------------
                           Orin Hirschman


                           ADAM SMITH CAPITAL MANAGEMENT, L.L.C.,

                           By: /s/ Richard Grossman
                               -------------------------------------
                               Richard Grossman, Manager


                           ADAM SMITH INVESTMENT PARTNERS, L.P.

                                    By: ADAM SMITH CAPITAL MANAGEMENT, L.L.C.,
                                    General Partner

                                    By: /s/ Richard Grossman
                                        -----------------------------
                                           Richard Grossman, Manager


                           DIAMOND CAPITAL MANAGEMENT INC.

                           By: /s/ Richard Grossman
                               -------------------------------------
                                  Richard Grossman, Vice President


                                     - 11 -


                           ADAM SMITH INVESTMENTS, LTD.


                                    By: DIAMOND CAPITAL MANAGEMENT INC.,
                                        investment advisor

                                    By: /s/ Richard Grossman
                                        --------------------------
                                        Richard Grossman


                           RICHARD AND ANA GROSSMAN JTWROS

                           By: /s/ Richard Grossman
                               -----------------------------------
                               Richard Grossman

                           By: /s/ Ana Grossman
                               -----------------------------------
                               Ana Grossman