Bones and Sulphuric Acid as Manures. 
463 
1st. The bones to be employed may be burnt, boiled, or fresh. 
If burnt, they contain nothing but the earthy constituents; if 
boiled, they hold also their gelatine ; and if fresh, they retain the 
whole of their animal matter (both fat and gelatine) as well their 
earthy matter. The animal substance being a rich manure, it 
would appear that these fresh bones ought to be preferred in all 
cases as a manure ; it has, however, been shown that this is not 
the fact, as the oil they contain prevents the plant, in such cases, 
from making full use of the other matters, the phosphates, &c., 
in the bone, which are of still more essential use. For the 
purpose, however of this application I should recommend the 
use of bones which contain as much of their animal matter as 
possible, as the acid acts upon the earthy part, frees it from the 
animal gelatine and oil, and prepares it for the plant at the same 
time that that animal part is set at liberty to serve its purpose; 
so that it would be bad economy either to destroy the animal por- 
tion of the bone by fire or to give the same price for such as 
for fresh ones for the purpose of this application. It is true that 
calcined bones are more easily dissolved ; if, however, either 
Ijoiled or raw bones be ground fine the acid will act upon them 
powerfully. But even should there be a few small portions of the 
bone imperfectly dissolved, I consider this no disadvantage, as 
they will act at the latter periods of the growth of the crop ; for it 
will be seen, from the foregoing experiments, that the effect of 
the preparation is to make the plants grow quickly — a proof that 
they find plenty of accessible food — and that, in one or two cases, 
they appeared to fail in iheir vigour towards the end of the season 
— a circumstance probably arising from the too fine state of division 
in which the bone was. And this takes place, it will be seen by 
a reference to my experiment, most especially where buriit bones 
are dissolved. There is no necessity, therefore, to ivaste tlie 
organic portion of the bone in order to be able to bring it into a 
state of division which is really not so useful as that into which 
we can bring it without the loss of the animal portion. Whether 
this reasoning be correct or not, facts (as my detailed experiments 
show) prove the conclusion, that the unburnt bones are preferable 
to use in this form. 
The quantity of dissolved bones most proper to be applied per 
acre is, practically speaking, an unsolved problem. Theory, 
however, says that, as the whole of the phosphates required for 
three crops is not more than 66 lbs. of bone-dust contains, it is fair 
to presume that, by giving the plant a chance, as we do by dis- 
solving the bones, of making use of nearly all the tillage that we 
put in the soil, a very small quantity will suffice for the turnip 
crop; and, having foiuid theory correct in the principle of the 
application, I do not see why we should doubt tliat practice will 
