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THE ELEMENTS AND THE SOIL 



Composition of the ash of leading farm crops (Snyder) 



Chemical Compounds 



The chemist uses initials (or other letters) to designate the elements, 

 when he makes a formula to express the composition of any compound ; 

 and he adds a figure to each symbol when more than one part or atom 

 (by atomic weight) enters into the make-up of the molecule. Thus 

 H 2 represents a compound in which the molecules are two parts 

 hydrogen and one part oxygen; in common language, this particular 

 compound is known as water. K 2 is potash (or potassium oxid) 

 two parts potassium and one part oxygen. Gypsum or land-plaster 

 is calcium sulfate, CaS0 4 , which means calcium one part, sulfur 

 one part, oxygen four parts. Quartz is Si0 2 . Quicklime is CaO. 



