LETTER OF TRANSMITTAL. 



U- vS. Departmext of Aoricultt're. 



Bureau of Plant Industry. 



Office of the Chief, 

 Washhu/toH. I), r., March 20, 1907. 

 Sir: I have the honor to transmit herewith a manuscript contain- 

 inf^ a review of all the work that has been done up to the present time 

 in the investigation of the use of finely ground feldspathic rocks as 

 fertilizers. There is a constantly growing demand for accurate 

 information on this subject, and I therefore recommend that this 

 manuscript be published as Bulletin No. 104 of the Bureau of Plant 

 Industry. 



Respectfully, B. T. Galloway, 



Chief of Bureau. 

 Hon. James "Wilson, 



Secretary of Agriculture. 



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