MANURE. 185 



Bone itself is allied to proteine by its cartilage, which 

 composes nearly one-third the weight, and which boiling 

 water, under pressure, completely extracts in the form of 

 gelatine, or glue. 



219. All these varied forms of proteine may be tabulated 

 so as to express, at a glance, their relation to each other, if 

 the elements. Carbon, Hydrogen, Nitrogen, and Oxygen, are 

 expressed by C. H. N. O., and to each are added figures 

 which represent the number of atoms entering into the com- 

 pound. This is called chemical notation, and each set a 

 chemical formula. (55.) 



Proteine, 



Gelatine of tendons, 

 Chondrine, or gelat. of rib cartilage, 

 Compact horny matter, hair, . 

 Feathers, ..... 



But the great practical lesson, taught by this similarity of 

 constitution, is, that it enables the chemist to present at one 

 view, animal and vegetable substances, * as carbon, water, 

 ammonia, and carburetted hydrogen. This is the view 

 •which the farmer takes, for he knows that these are the ele- 

 ments of manure. Proteine may be resolved into : 



Hydrogen. 



p , ) 4.2424-0.707= 4.949 Carb. hydrogen, 



uarbon, ^ ^^^^^ 51.500 Carbon. 



Oxygen, 21 .288 -f 2.G61 = 23.949 Water. 



Nitrogen, 16.143 + 3.459 = 19.602 Ammonia. 



93.173 + 6.827= 100. Proteine. 



This is the agricultural view, and expresses at once that 

 this great variety of substances is compared to cow-dung as 

 32 to 1, when used dry as manure, dung being 1, and pro- 



