ANIMAL MANURES. 1 'M 



iiemistry of agriculture, Baron Liebig says, that "the most 

 easy and practical method of effecting the division of bones, 

 is to pour over them half their weight of sulphuric acid, 

 diluted with three or four parts of water, and after they have 

 been digested for some time, to add about one hundred parts 

 of water, and to sprinkle the mixture before the plough. In 

 a few seconds, the free acids unite with the bases contained 

 in the earth, and a neutral salt is formed, in a state of very 

 fine division. Experiments, instituted on a soil formed from 

 (Jrauwacke (126), for the purpose of ascertaining the action 

 of the manure thus prepared, have distinctly shown, that 

 neither com nor kitchen plants suffer injurious effects in 

 consequence, but that, on the contrary, they thrive with 

 much vigour." 



204. The difficulty of applying liquid manure, which re- 

 quires water-carts, and arrangements not generally accessible 

 to farmers, suggested other methods of applying " dissolved 

 bones," which are now usually adopted. It has been found, 

 that by drying up the liquid mixture, by the addition of dry 

 peat-mould, by sawdust, or even by vegetable earth, it could 

 be converted into a form in which it might be more conve- 

 niently used by the majority of farmers. 



205. The chemical changes produced upon bones by the 

 action of sulphuric acid, which is the acid now usually em- 

 ployed, are very important. When the diluted acid is 

 poured upon the bones, there is at first a violent frothing 

 up or effervescence, such as we observe when we pour vitriol 

 upon pieces of limestone. This effervescence is produced 

 by the rapid disengagement of carbonic acid, which is a 

 constituent of both limestone and bones; and, in both cases, 

 the same compound, sulphate of lime, or, as it is commonly 

 termed, gijpmm, is produced. But bones, as the analysis 

 shows, in addition to the compound of carbonic acid and 

 lime, which is one of their ingredients, also contain a large 

 amount (5 8 J per cent) of the insoluble phosphates. The 

 sulphuric acid also unites with a portion of the lime, in these 

 compounds; while the excess of the compound of phos- 

 phorus (phosphoric acid) which is separated, unites with the 

 remainder of the lime, to produce a new compound, which, 

 from containing a larger amount of phosphorus than the 

 original phosphates, is termed super-phosphate of lime. This 

 new phosphate is soluble in water, and is, therefore, capable 



