Exhibit
10.4

     

    Execution Copy

     

     

    The Dow
Chemical Company

    2030 Dow
Center

    Midland,
Michigan 48674

     

    March 9,
2009

     

    
      Paulson
& Co. Inc.

      1251
Avenue of the Americas, 50th
Floor

      New York,
NY  10020

      
        	Attn:	Michael
      Waldorf
	 	Senior Vice
      President


      

       

          

       

      Letter
Agreement

       

      In
consideration of you entering into the Investment Agreement dated as of March 9,
2009 (the “Investment
Agreement”), among The Dow Chemical Company (“Parent”) and the
Investors named therein (the “Investors”), Parent
and Ramses Acquisition Corp. (“Ramses”) hereby agree
with you to use their respective best efforts to consummate by April 1, 2009,
the merger (the “Merger”) in
accordance with the terms and conditions of the Agreement and Plan of Merger
dated as of July 10, 2008 (the “Merger Agreement”),
among the Company, Ramses and Rohm and Haas Company, including, without
limitation, using best efforts to cause the lenders party to the Term Loan
Agreement (the “Term
Loan Agreement”) dated as of September 8, 2008, as amended as of March 4,
2009 to provide funds necessary to consummate the Merger and, if for any reasons
such funds shall not be available or are insufficient in amount, arrange for
such additional or substitute funding as may be necessary to do so.

       

      In
addition to and without limiting the foregoing, Parent and Ramses hereby agree
with you to consummate by April 1, 2009 the Merger, subject only to (a) the
condition set forth in Section 6.1(b) of the Merger Agreement, (b) the condition
set forth in Section 6.3(b) insofar as it relates to compliance on and after the
date hereof by the Company with any covenants contained in the Merger Agreement
that by their terms contemplate performance on or after the date hereof and (c)
the condition that each of the Investors fund its obligations under Sections
1.01 and 1.03 of the Investment Agreement.

       

      The
liability of Parent and Ramses for any breach of the second paragraph of this
letter agreement shall not exceed $500,000,000.  In addition, neither
Parent nor Ramses shall have any liability under the second paragraph of this
letter agreement in the event that (x) funds are not made available under the
Term Loan Agreement because either (A) one or more of the conditions contained
in the Merger Agreement to Parent’s obligations to consummate the Merger is not
satisfied or waived and one or more of the banks assert that such failure of
such conditions relieves such bank or banks of their obligations under the Term
Loan Agreement to fund loans or (B) such banks fail to fund in violation of the
Term Loan Agreement or (y) any of the banks with the four largest funding
commitments under the Term Loan Agreement files for bankruptcy or becomes
subject to similar proceedings and the trustee in bankruptcy (or comparable
entity)

    

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    

     

    
      rejects
the obligation of such bank under the Term Loan Agreement to fund loans, so long
as in the case of either clause (x)(B) or clause (y) Parent and Ramses have
complied with their obligations under the first paragraph of this letter
agreement.

       

      This
letter agreement may not be amended or any provision hereof waived or modified
except by an instrument in writing signed by each of the parties
hereto.  This letter agreement may be executed in any number of
counterparts, each of which shall be deemed an original and all of which, when
taken together, shall constitute one agreement.  Delivery of an
executed counterpart of a signature page of this letter agreement by facsimile
or electronic transmission shall be effective as delivery of a manually executed
counterpart of this letter agreement.

       

      This letter agreement shall be
governed by, and construed in accordance with, the laws of the State of
Delaware.  The parties hereto agree that any dispute arising
out of this agreement shall be litigated exclusively in the Court of Chancery of
the State of Delaware.

    

     

    [Remainder
of page intentionally left blank]

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    

     

    If the
foregoing is in accordance with your understanding, please sign and return to
the undersigned the enclosed copy of this letter.

     

    
      
        
          
            
              
                
                  
                    
                      
                        	 	Very
      truly yours, 	 
	 	 	 
	 	 	 
	 	THE
      DOW CHEMICAL COMPANY, 	 
	 	 	 	 	 
	 	 	by 	 	 
	
                                 

                              	 	
                                 

                              	/s/
      ANDREW N. LIVERIS	 
	 	 	 	Name:
      Andrew N. Liveris 	 
	 	 	 	Title:   Chief
      Executive Officer 	 
	 	 	 	 	 


                      

                    

                  

                

              

            

          

        

      

    

     

     

     

    
      	
            	RAMSES
      ACQUISITION CORP., 	 
	 	 	 	 	 
	 	 	by 	 	 
	
               

            	 	
               

            	/s/
      ERIC P. BLACKHURST	 
	 	 	 	Name:
      Eric P. Blackhurst 	 
	 	 	 	Title:   Vice
      President and Secretary	 
	 	 	 	 	 


    

     

     

    
      
        [Signature
Page to Letter Agreement (Paulson & Co.)]

        
        

      

      
        
        

        
          

        

      

      
        
        

      

    

     

    Agreed
to and accepted as of the date first written above:

    


     

    
      
        	
                
                  PAULSON
      & CO. INC.

                  on
      behalf of the several funds and accounts
managed by
      it

                

              	 
      
	 	 
	
                by

              	 
      
	 
      	
                /s/
      MICHAEL
      WALDORF

              	 
      
	 
      	
                Name:
      Michael
      Waldorf

              	 
      
	 
      	
                Title:  
      Senior Vice President

              	 
      


      

    

    


    
       

       

       

       

       

       

       

       

       

       

    

     

     

     

     

     [Signature
Page to Letter Agreement (Paulson & Co.)]