CHEMICAL FERTILIZERS. Ill 



MEETING FOR DISCUSSION. 



Saturday, March 25, 1876. 



W. C. Strong, Chairman of the Committee on Publication and 

 Discussion, in the chair. The meeting was opened by the reading 

 of the following paper : 



Chemical Fertilizers. 



BY HENRY F. FRENCH. 



At the request of your Committee I have consented to read at 

 this meeting a paper on Chemical Fertilizers, a subject upon which 

 I claim to have no peculiar knowledge, beyond what may be ac- 

 quired by any careful observer and reader. I am no chemist, and 

 shall not attempt to speak with scientific exactness. There are 

 certain theories and conclusions, however, in which all modern 

 chemists agree, and which it is well for us to bear iij mind in this 

 discussion. 



The third edition of " Liebig's Agricultural Chemistry," which I 

 happen to own, was published in 1843. At that time the analysis 

 of plants, and of soils, and of fertilizing agents, with reference to 

 supplying to the soil the elements of plant growth, seems to have 

 been a familiar subject of scientific research. Chemical analysis 

 had alread}^ shown clearly of what elements plants are constituted, 

 and that certain of these are derived in abundance from the at- 

 mosphere and water, and certain others are derived chiefly from 

 the soil. It had also been ascertained that most soils contained 

 inexhaustible supplies of some of these elements, as, for instance, 

 of silica ; and that most soils did not contain enough of certain 

 other elements, as potassa and phosphoric acid, to produce many 

 crops, without restoring, in some form, these essential elements. 



It was also well understood that different plants contained these 

 essential elements in different proportions, and consequently that 

 the food furnished thend should contain these elements in the pro- 

 portions in which they were found by analysis to exist in the 

 plants. We find that this idea was so familiar that Liebig and the 

 men of his time, spoke of certain classes of plants as potash 



