50 ORIGIN OF THE ELEMENTS OF SOIL. 



elements are Protean, and assume new dresses, by 

 the very processes adopted to unfold them. What- 

 ever may be their origin, their constant presence 

 leads to this fifth principle of Agricultural Chemistry, 



THAT ALL SOIL CONTAINS SULPHATE AND PHOSPHATE 

 OF LIME. 



85. This principle is of the highest importance in 

 agriculture. The author of these pages, stated the 

 fact, to the Geological Surveyor of Massachusetts, 

 in 1837, and it was published in his Report. Slow- 

 ly admitted at first, the fact, that phosphates exist in 

 all soil, has been established by the widest observa- 

 tions. Its proofs are both chemical and agricultural. 

 The chemical proof is found in the extensive anal- 

 yses of soil, contained in the various Geological 

 Reports, especially those of Massachusetts, publish- 

 ed within a few years. The agricultural proof, may 

 be stated in a few words. 



86. First, the bones of all graminiverous animals ? 

 contain half their weight of phosphate of lime. It 

 can be derived only from their food, and that only 

 from the soil. Hence, the soil contains phosphoric 

 acid in some chemical combination. Secondly, the 

 actual result of chemical analysis, confirms this 

 statement. Beets, carrots, beans, peas, potatoes, 

 asparagus, cabbage, afford phosphates of lime, mag- 



