Reviews. — Liebig^s Organic Chemistry. 353 



bones contain as much phosphate of lime as one thousand pounds of 

 hay or wheat-straw, and two pounds of it as much as one thousand 

 pounds of the grain of wheat or oats. These nuiTibers express pretfy 

 exactly the quantity of phosphates which a soil yields annually on the 

 jjrowth of hay and corn. Now the manure of an acre of land with 

 forty pounds of bone dust is sufficient to supply three crojjs of wheat, 

 clover, potatoes, turnips, &c. with phosphates. But the form in 

 which they are restored to a soil does not appear to be a matter of 

 indifference. For the more finely the bones are reduced to powder, 

 and the more intimately they are mixed with a soil, the more easily 

 are they assimilated. The most easy and practical mode of etTectin^ 

 their division is to pour over the bones, in a state of fine powder, 

 half of their weight of sulphuric acid diluted with three or four parts 

 of water, and after they have been digested for some time, to add one 

 hundred parts of water, and sprinkle this mixture over the field be- 

 fore 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 very 

 fine state of division. Experiments instituted on a soil formed from 

 grauwacke, for the purpose of ascertaining the action of manure 

 thus prepared, have distinctly shown that neither corn, nor kitchen- 

 garden plants, suffer injurious effects in consequence, but that on the 

 contrary they thrive with much n)ore vigor. 



In the manufactories of glue, many hundred tons of a solution of 

 phosphates in muriatic acid are yearly thrown away as being useless. 

 it would be important to examine whether this solution might not be 

 substituted for the bones. The free acid would combine with the 

 alkalies in the soil, especially with the lime, and a soluble salt would 

 thus be produced, which is knovvn to possess a favorable action upon 

 the growth of plants. This salt, muriate of lime (or chloride of cal- 

 cium,) is one of those compounds which attracts water from the at- 

 mosphere with great avidity, and might supply the ])lace of gypsum 

 in decomposing carbonate of ammonia, with the formation of sal-am- 

 moniac and carl)onate of lime. A solution of bones in muriatic acid 

 placed on land in autumn or in winter would, therefore, not only re- 

 store a necessary constituent of the soil, and attract moisture to it, 

 but would also give it the power to retain all the ammonia which fell 

 upon it dissolved in the rain during the period of six months. 



The ashes of brown coal and peat often contain silicate of potash, 

 BO that it is evident that these might completely replace one of the 

 principal constituents of the dung of the cow and horse, and they 

 contain also some phosphates. Indeed, they are much esteemed in 

 the Wetterau as manure for meadows and moist land. 



It should, in justice, be remarked, that the author does not 

 depreciate the immense value of anirnal manures; and, from 

 subsequent remarks, we should infer that the urates and pou- 

 drettes of our manufactories were likely to effect an im- 

 portant change in the features of tillage, founded, in their pre- 

 paration, on the more elegant application of the most stimu- 

 lating n)anures to culture. 



As the topics of agricultural pursuits are more in accord- 



VOL. VII. — NO. IX. 45 



