1 36 LESSONS IN CHEMISTRY. 



equal weights of crushed bones and good Patagonian guano, 

 applied to the same field, do not, it has been found, produce 

 an equal return. 



202. The experience of farmers shows, that, weight for 

 weight, the guano, especially on dry and sandy soils, is capa- 

 ble of yielding larger crops. This superiority of guano is to 

 be explained, first, by the fine state of division in which its 

 constituents are presented to the soil; and, in the second 

 place, by the readiness with which its organic matters yield 

 up their ammonia. Bones cannot, without difiiculty, be 

 reduced to a coarse powder, except by the assistance of 

 powerful and expensive machinery. Placed in the soil in a 

 coarse state, they decay but slowly; and ndfany years must 

 elapse before all their ingredients are converted into a form 

 in which they can produce their effects upon the crops of the 

 farmer. The fanners, in some parts of Scotland, are accus- 

 tomed to apply tliem broken into half-inch and three-quarter 

 inch pieces ; but in this state their application will not be 

 productive of the immediate results which are observed when 

 they are applied in a more minutely divided state, and 

 which, especially for the tm-nip-crop, it is most important to 

 produce. 



203. In England, various plans have been adopted to 

 secure their more ready decomposition. Some persons place 

 them in a heap, covered over with earth, and allow them to 

 heat and ferment, by which means their decomposition, when 

 placed in the soil, is considerably accelerated; others, again, 

 mix them with farm-yard manure, and leave them to ferment. 

 Both plans are useful; but to chemistry the practical farmer 

 is indebted for another mode of effecting their division, which 

 far surpasses any method hitherto attempted, and which has, 

 dming the last two or three years, been extensively adopted, 

 with the most signal success, — I allude to the decomposition 

 of bones by the action of sulphuric acid (vitriol), or of 

 muriatic acid (spirits of salts). By means of these cheap 

 and well-known acids, it has been found, that they can be 

 converted into the most effective and economical form in 

 which they can be given to the soil. For this valuable 

 method, the English agriculturist is indebted to that great 

 man, whose writings have done so much to direct public 

 attention, in this country, to the services which science is 

 capable of rendering to the farmer. In his report on the 



