152 MANURES. 



as densely peopled as Great Britain, yet while Grea* 

 Britain imports immense quantities of grain, guano_ 

 bones, and other fertilizers, and pours its immense 

 vohnnes of manure into tlie sea, Japan neither 

 wastes nor imports. The bread of its people is raised 

 on its tields, which have been cultivated for un- 

 counted ages, wliile every scrap of fertilizing matter 

 is saved with scrupulous care. 



It is true that the processes by which manure is 

 saved and applied in China and Japan are not nice, 

 but it is saved, nevertheless, and the fact that our 

 chemical knowledge enables ns to accomplish the 

 same result in an inoffensive manner, should make 

 us all the more earnest in mending our ways. 



Many suppose that soils which produce good crops, 

 year after year, are inexhaustible, but time invariably 

 proves the contrary. They may possess a suffi- 

 cientlj' large stock of phosphoric acid, and other plant 

 constituents, to last a long time, but when that stock 

 becomes so reduced that there is not enough left for 

 the uses of full crops, the productive power of the 

 soil will yearly decrease, until it becomes worthless. 

 It may last a long time — a century, or even more — 

 but as long as the system is to remove everything^ 

 and 7'eturn nothing^ the fate of the most fertile soil 

 is certain. 



As has been stated already-, the constituent of the 

 soil which is most likely to become deficient \% phos- 

 2?lwric acid. One principal source from -which this 

 ca" be obtained is found in the bones of animals. 



These contain a large proportion of jphosi^hate of 



