LETTER OF TRANSMITTAL 



U. S. DEPARTMENT OF AGRICULTURE, 



BUREAU OF CHEMISTRY, 



Washington, D. <?., July 20, 1903. 



SIR: I have the honor to transmit herewith for your approval a 

 manuscript embodying the results of the tests conducted in the Road 

 Material Laboratory of this Bureau since its establishment by you in 

 October, 1900, together with an exposition of the methods used in 

 obtaining these results, and to recommend that this report be published 

 as Bulletin 79 of the Bureau of Chemistry. I beg to make acknowl- 

 edgment of the cordial cooperation of the Office of Public-Road 

 Inquiries in these investigations, without which this work could not 

 have been done. 



The illustrations., which comprise five half-tone photos and ten text 

 figures, are regarded as necessary to a clear understanding of the text. 

 Respectfully, 



H. W. WILEY, 



Chief. 

 Hon. JAMES WILSON, 



f<ii'i/ <>f Ayr ''culture. 



