17C ON MANURE. 



A part of the crop taken from a field is used in feeding and 

 fattening animals, which are afterwards consumed by man. 

 Another part is used directly in the form of potatoes, meal, or 

 vegetables ; while a third part, consisting of the remnants of 

 plants, are employed as litter in the form of straw, &c. It is evi- 

 dent that all the constituents of the field removed from it in the 

 form of animals, corn, and fruit, may again be obtained in the 

 liquid and solid excrements of man, and in the bones and blood 

 of the slaughtered animals. It altogether depends upon us to keep 

 our fields in a constant state of composition and fertility by the 

 careful collection of these substances. We are able to calculate 

 how much of the ingredients of the soil are removed by a sheep, 

 by an ox, or in the milk of a cow,* or how much we convey 

 from it in a bushel of barley, wheat, or potatoes. From the 

 known composition of the excrements of man, we are also able to 

 calculate how much of them it is necessary to supply to a field 

 to compensate for the loss that it has sustained, 



It is certainly the case, that we could dispense with the excre- 

 ments of man and animals, if we were able to obtain from other 

 sources the ingredients on which depends all their value for agri- 

 culture. It is a mafter of no consequence whether we obtain 

 ammonia in the form of urine, or in that of a salt from the pro- 

 ducts of the distillation of coal ; or whether we obtain phos- 

 phate of lime in the form of bones, or as the mineral apatite. The 

 principal object of agriculture is to restore to our land the sub- 

 stances removed from it, and which the atmosphere cannot yield; 

 in whatever way the restoration can be most conveniently effected. 



* 1000 parts of milk yielded, by incineration — 



1 677 Residue. 



II. 49-0 



100 parts of the ashes of the milk consisted of: — 



Phosphate of lime . 

 " magnesia 



Perphosphate of iron 

 Chloride of potassium 

 Co union mtt 

 Soda . . . 



