AGRICULTURE WITH CHEMISTRY. j^j 



composition of water in the process of vegetation, for 

 the matter of which it principally consists. To these two 

 causes the accumulation of vegetable matter on the svirface 

 of the earth is principally to be ascribed. It would not be 

 an easy task to ascertain the different proportions of the 

 food of plants supplied from the soil, or from the air, and 

 the decomposition of water. It must be admitted, that the 

 constituent principles of the vegetable substances con- 

 tained in ground long under cultivation, have, in a great 

 measure, been supplied to such vegetables, when growing, 

 by air and water. This must be evident from the large 

 proportion of vegetable and animal matter (under all states 

 or systems of cultivation or cropping) annually taken 

 from the soil, consisting of grain, or animal sub- 

 stances, such as flesh, milk, butter, and cheese; the 

 dung and urine of cattle dropi)ed on the roads, (where 

 it is totally lost) and the large proportion of the food 

 of animals, thrown off by insensible perspiration and 

 breathing: to all which must be added the quantity 

 of cxtraflive soluble matter annually washed away by the 

 rains, and carried into the sea. Had not the benevolent 

 Cre:.tor of all things established processes for supplying 

 such ail unavoidable waste of vegetable or other matters, 



the 



