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               THIRD AMENDMENT TO AGREEMENT OF PURCHASE AND SALE


         This Third Amendment to Agreement of Purchase and Sale (this
"Amendment") is entered into effective as of the 22nd day of December, 1998, by
and among LINCOLN-WHITEHALL REALTY, L.L.C., A DELAWARE LIMITED LIABILITY
COMPANY, LINCOLN-WHITEHALL PACIFIC, L.L.C., A DELAWARE LIMITED LIABILITY
COMPANY, WHLNF REAL ESTATE LIMITED PARTNERSHIP, A DELAWARE LIMITED PARTNERSHIP,
AND WHSUM REAL ESTATE LIMITED PARTNERSHIP, A DELAWARE LIMITED PARTNERSHIP
(EACH, "SELLER", AND COLLECTIVELY, THE "SELLERS"), and AMERICAN INDUSTRIAL
PROPERTIES REIT, A TEXAS REAL ESTATE INVESTMENT TRUST ( "BUYER ").

                              W I T N E S S E T H:

         WHEREAS, Sellers and Buyer have entered into that certain Agreement of
Purchase and Sale dated November 12, 1998, as amended by an Amendment to
Agreement of Purchase and Sale dated effective November 23, 1998 and by an
Amended and Restated Second Amendment to Agreement of Purchase and Sale dated
effective December 11, 1998 (collectively, the "Agreement"), pursuant to which
Sellers have agreed to sell and Buyer has agreed to purchase certain real
properties comprising the "Lincoln-Whitehall Portfolio," as more particularly
described therein; and

         WHEREAS, the parties hereto desire to amend the Agreement, as more 
fully set forth herein;

         NOW, THEREFORE, in consideration of the premises and the mutual
covenants agreements herein contained, and for other good and valuable
consideration, the receipt and sufficiency of which is hereby acknowledged, the
parties hereto agree as follows:

1.                The reference to "December 22, 1998" contained in the
                  definition of "Due Diligence Period" (as defined in Section
                  1.1 of the Agreement) is hereby amended to read "December 23,
                  1998."

2.                The reference to "December 22, 1998" contained in the
                  definition of "Second Deposit Date" (as defined in Section
                  1.1 of the Agreement) is hereby amended to read "December 23,
                  1998."

3.                The reference to "January 6, 1999" contained in Section 8.2 of
                  the Agreement is hereby amended to read  "January 15, 1999."

4.                The Agreement, as amended by this Amendment, is hereby
                  ratified and confirmed and remains in full force and effect.

         EXECUTED effective as of the day and year first above written.



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                      "BUYER"

                      AMERICAN INDUSTRIAL PROPERTIES REIT,
                      a Texas real estate investment trust

                      By:   /s/  MARC A. SIMPSON
                            -----------------------------------------
                      Name:      Marc A. Simpson
                            -----------------------------------------
                      Title:     Senior V-P
                            -----------------------------------------


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                     "SELLERS"

                     LINCOLN-WHITEHALL REALTY, L.L.C.,
                     a Delaware limited liability company

                     By:    Whitehall Street Real Estate Limited Partnership V,
                            Member
 
                            By:  WH Advisors, L.P. V
                                 General Partner

                                 By:  WH Advisors, Inc., V,
                                      General Partner

                                      By:    /s/  DAVID M. WEIL
                                             ----------------------------------
                                      Name:       David M. Weil
                                             ----------------------------------
                                      Title:      Vice President
                                             ----------------------------------

                     LINCOLN-WHITEHALL PACIFIC, L.L.C.,
                     a Delaware limited liability company

                     By:    Lincoln-Whitehall Realty, L.L.C.
                            Member

                            By:  Whitehall Street Real Estate Limited
                                 Partnership V,
                                 Member

                                 By:  WH Advisors, L.P. V,
                                      General Partner

                                      By:  WH Advisors, Inc., V,
                                           General Partner
 
                                           By:   /s/  DAVID M. WEIL
                                                 ------------------------------
                                           Name:      Dacid M. Weil
                                                 ------------------------------
                                           Title:     Vice President
                                                 ------------------------------


                     WHLNF REAL ESTATE LIMITED PARTNERSHIP,
                     a Delaware limited partnership

                     By:    WHLNF Gen-Par, Inc.,
                            General Partner

                            By:   /s/ DAVID M. WEIL
                                  ------------------------------------
                            Name:     David M. Weil
                                  ------------------------------------
                            Title:    Vice President
                                  ------------------------------------



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                    WHSUM REAL ESTATE LIMITED PARTNERSHIP,
                    a Delaware limited partnership

                    By:     WHSUM Gen-Par, Inc.,
                            General Partner

                            By:   /s/ DAVID M. WEIL
                                  ------------------------------------
                            Name:     David M. Weil
                                  ------------------------------------
                            Title:    Vice President
                                  ------------------------------------