96 



ANIMAL MANURES'. 



mills, are both considered valuable in England; they 

 are sold there at from $20 to $40 per ton, and are 

 eagerly sought after at these prices, as not only very 

 fertilizing, but also very lasting in the soil. All of 

 the hair obtained from the furs of animals is there 

 scrupulously saved, and sold at a high price. Twenty 

 or thirty bushels per acre produce an excellent effect. 

 All these parts of the animal leave an ash corre- 

 sponding with that of plants in the substances which 

 it contains, with the single exception of silica; this 

 does not seem to enter into the composition of the 

 animal. We are then now able to point out distinc- 

 tions between the inorganic matter in the soil, in the 

 plant, and in the animal. They all contain the same 

 substances, if w r e omit silica and alumina. 



table v. 



The soil contains silica and alumina. 

 The plant contains silica, but no alumina. 

 The animal contains neither silica nor alumina. 



SECTION V. OF BONES. 



There is one important part of the animal yet un- 

 noticed, that is the bones. Their composition is, when 

 dry, earthy matter about 66 lbs. in 100; organic mat- 

 ter that burns away, about 34 lbs. 



a. This earthy matter consists for the most part of 

 phosphate of lime, that is, lime in combination with 

 phosphoric acid ; these, as already shown, are two 

 most valuable substances for application to any soil. 



b. The organic part is called gelatin, or glue; this 

 is boiled out by the glue-makers : it is extremely rich 

 in nitrogen, and is therefore an excellent manure. We 

 thus see, at once, how important a source of nourish- 

 ment for our land is to be found in bones. They unite, 

 from the above statement, some of the most efficacious 



