456 Bones and Suljjkuric Acid as Manures. 
destroy an agent which is vahiable. Thus, in order to get a ready 
supply of phosphates, we, in the case of burnt bones, waste both 
the fat and gelatine — while, even in boiled bones, the oil is for 
the same purpose extracted ; in this case, however, we get a 
tillage superior to burnt bones, inasmuch as, while its phosphates 
are obtainable by the vegetable, it has also a fund of animal 
manure, and superior to green bones, inasmuch as, while it has 
a good share of the organic, its inorganic elements are not in- 
active." " Would it not, therefore," adds she, " be desirable 
to devise a means by which both the animal and the earthy part 
of bone manure may each be made to serve its own pecuhar 
purpose in the vegetable economy without injury to the other ; 
so as to prevent the waste of the animal part in order to prepare 
it for the crop, or of the phosphates by their not being ready for 
the roofs ? If" so, it is in my power to suggest means by which bones 
may be reduced to the finest state of division, and vised in such a 
form that the earthy parts may be readily assimilated, and the 
animal matter set at liberty to mingle in the soil and to perform 
its part in promoting vegetation, so that a great saving may be 
effected in the quantity used, owing to the nature of the mix- 
ture rendering it not necessary to apply more than the plant re- 
quires — which is but a small proportion of the quantity applied 
in their crude state." * 
The means proposed to carry out these aims, need I add, were 
those to which our attention is now dra^Ti, viz. to reduce the bones 
by the action of sulphuric or muriatic acid and water to the finest 
state of division, and to add water so as to be able to apply the 
manure in the form of a solution. In this process with sulphuric 
acid the earthy part is extracted from the animal, the acid com- 
bines with a portion of the lime (forming gypsum), while the 
remainder of the acid, and the remainder of the lime originally 
composing the pliosphate, are dissolved, and form a double phos- 
phate. This solution therefore contains a biphosphate of lime, in 
which the phosphoric acid exists in a much greater quantity than 
in the ordinary phosphate of lime which exists in bone.f 
With muriatic acid a muriate of lime, and a biphosphate, is 
formed in a similar manner. This muriate of lime is a salt 
which attracts moisture greatly. 
By this process the bone earth is rendered in a fine state of 
division; the free acids unite with the bases contained in the earth, 
and form other salts beneficial to vegetation; and the whole of 
* "The whole of the phosphates required by three crops, is contained," 
gays Liebig, " in G6 lbs. of bone-dust." 
t The biphosphate, free from water, contains 71^ per cent, of phosphoric 
acid, and 28^ of lime ; while the bone earth phosphate consists of 48^^ per 
cent, of phosphoric acid, and 51^ of lime. 
