AGRICULTURAL TEXT-BOOK. 323 



equal to at least eightjthat have been exposed. The best mode of saving sheep manure 

 is to keep the sheep under sheds, giving sufficient straw to keep them clean. Not 

 only is much manure thus saved, but less food is consumed, and the sheep are much 

 more profitable. (Sec Farmer 3 Companion and Horticulural Gazette, VOL. l,p. 6, 

 64.) 



700. In America, the European mode of making composts of barji 

 yard manures and other substances is not much employed. It is not 

 only a greater expense of manual labor, and lower value of produce 

 which forbid it, but there are serious reasons for believing that with our 

 very hoi summer climate, and comparative want of showers, composts 

 will not act as effectively with us as they do in the Eastern Hemisphere. 

 The subject, however, docs not appear to have been yet tested by ex 

 periment, and we can only speak theoretically. 



There are many other sources of animal manures enjoyed in various 

 parts of the world, but which at present are of no practical interest to 

 Western farmers. 



701. MINERAL MANURES. 



By this term we mean all substances of an inorganic nature, 

 all of which are derived, either directly or indirectly, from the 

 soil, such as wood and coal ashes, plaster, (fee. 



WOOD ASHES. These are the remains of trees, after the or 

 ganic or vegetable matter has been consumed (driven off in the 

 shape of gas,) by fire ; and consequently, while they all bear a 

 general resemblance, they differ much in the relative proportion 

 of the constituents, according to the trees and soils from which 

 they are derived. As manures they have a two fold action ; 

 (a,) they supply to the plant the inorganic constituents which 

 it requires; (b,) they act chemically as solvents upon other in 

 soluble salts already in the soil ; or they neutralize acids, &amp;lt;fcc. 



702. When we have burnt a tree and collected the ashes 

 we find that they consist of two portions, those that are soluble 

 in water and those that are insoluble. The average quantity of 

 ashes from 100 parts of dry oak, beech, birch, &c., is 2.87. 100 

 parts of such ashes afford 13.57 parts soluble; 86.43 parts in 

 soluble, the latter being left behind at our ash works, while the 

 soluble have been boiled down and exported as potash. Pine 



