LETTER OF TRANSMITTAL 



U. S. DEPARTMENT OF AGRICULTURE, 



BUREAU OF CHEMISTRY, 

 Washington, D. C., March 3, 1905. 



SIR: I beg to transmit herewith for your inspection and approval 

 the manuscript containing the data secured in the study of the effects 

 of water on rock powders, and to ask that it be printed as Bulletin 92 

 of this Bureau. This manuscript contains data of great practical inter- 

 est in connection with the selection and treatment of materials for 

 road building. It also presents facts of practical application respect- 

 ing the chemical reactions which go on in finely ground material 

 derived from rocks and certain artificial products. The illustrations 

 are necessary to the proper elucidation of the text. 

 Respectfully, 



H. W. WILEY, Chief. 

 Hon. JAMES WILSON, 



Secretary of Agriculture. 

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