MANURES. 158 



lime. They are the receptacles which collect nearly 

 all of the phosphates in crops which are fed to ani- 

 mals, and are not returned in their excrements. F..r 

 the grain, etc., sent out of the country, there is no 

 way to be repaid except by the importation of this 

 material; but nearly all that is fed to animals may, 

 if a proper use be made of their excrement, and of 

 their bones after death, be returned to the soil. With 

 the treatment of animal excrements we are already 

 familiar, and we will now turn our attention to the 

 subject of 



BONES. 



Bones consist, when dried, of about one-third or- 

 ganic matter, and two-thirds earthy matter. 



The organic matter consists chiefly of gelatine a 

 compound containing nitrogen. , 



The earthy part is chiefly phosphate of lime. 



Hence we see that bones are excellent, both as or- 

 ganic and as mineral manure. The organic part, con- 

 taining nitrogen, forms ammonia, and the inorganic 

 part supplies the much-needed phosphoric acid to the 

 soil. 



Liebig says that, as a producer of ammonia, 100 

 Ibs. of dry bones are equivalent to 250 Ibs. of human 

 urine. 



Bones are applied to the soil in almost every con- 

 ceivable form. Whole lones are often used in very 

 large quantities ; their action, however, is extremely 

 slow, and it is never advisable to use them in this 

 form. 



