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STUDIES IN SOIL PHYSICS 



By E. E. FREE 



Scientist, Bureau of Soils, 

 U. S. Department of Agriculture 



This series o. papers, which appeared in The Plant World during 



1911, has been revised by the author and is now 



offered in durable pamphlet form 



Single copies $ .75 Five copies $3.00 



This book is the most recent, informing, and suggestive treatment of 



a field of study which is of vital importance to botany, 



agriculture, and forestry. 



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THE PLANT WORLD TUCSON, ARIZONA 



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