FOREWORD 



" In some experiments on the action of green vitriol, 

 or sulphate of iron, dissolved in water and used 

 as manure, the results appear to vary exceedingly; 

 some persons have not been able to discover that it 

 produced the slightest effect, others have found i( 

 injurious, while a third class have declared they have 

 derived a considerable benefit from the use of it." 



— Thaer. 



TrllS is the first of a series of publications on 

 the use of Sulphate of Iron in Agriculture ; 

 beginning with the work of Thaer in Germany 

 who first called attention in 1809 to the use- 

 fulness of Sulphate of Iron in Agriculture, and 

 continuing to 1905. 



The material is not colored in any way, it is an 

 accurate record of work done. It will be pub- 

 lished from time to time in the form of an author's 

 index and subject index. n 



CHICAGO, February 20, 1906 



