150 
Superphosphate of Lime. 
the temperature is raised to 300' Fahr. It is therefore very de- 
sirable that sufficient water should be used to produce this great 
heat, which facilitates the dissolving process ; and the quantity 
above stated or, if more convenient, the same measure of water 
as of acid, which will be rather more than half the weight, will be 
a very good proportion. More should not be used, as no useful 
purpose will be accomplished. In an experiment tried last year 
with different proportions of water, I could not detect any dif- 
ference in the result. The water should be applied first by means 
of a watering-pot, so that it may be intimately combined with every 
portion of the bones. This is an important point, and greatly 
facilitates the dissolving process, which without it is very likely to 
be imperfectly accomplished. 
Another reason for applying the water first is, that the bones 
becoming partially saturated, the acid, from its great affinity for it, 
rushes as it were into the pores of the bones in search of the water, 
and thus the bones become more rapidly and perfectly mixed 
with and acted on by the acid. When no water is employed, and 
the bones are not entirely in the state of fine dust, as they never 
are unless purposely sifted, the surfaces of the small pieces of 
bones become acted on by the acid, and a coat forms around 
them which seals up the interstices of the bones and prevents the 
acid from penetrating. I have no doubt this is often the case 
likewise from careless or imperfect mixture, and the good effects 
of the manure are thus materially diminished. 
4. Mode of mixing the bones with the acid and of preparing 
the compost. 
It has been recommended that a large heap of ashes or mould 
should be made with a hole or depression on the top, in which 
the bones are to be placed, the acid poured over them, and after 
some time the whole shovelled up and mixed together. Now, 
if we examine into the effects of this mode of procedure, we shall 
readily perceive the objection to which it is subject. The ashes 
no doubt contain a considerable portion of carbonate of lime 
besides other salts, for which sulphuric acid has a very strong 
affinity. Thus the bones are robbed of a large proportion of 
the acid, of which they ought to have exclusive possession. And 
even if common mould is used, or any other substance which has 
no particular chemical affinity for the acid, still this mould will 
mechanically absorb much of the acid, and thus deprive the bones 
of it.* I hold it, therefore, as a point of much importance that 
* I have not found that any considerable quantity of the acid passes 
throu<jh the bones into the heap of ashes or earth; and though Mr. 
Spooner's is tlie better plan, where his apparatus can be easily procured, 
I still think that the expedient I mentioned may be found sometimes 
convenient. — Ph. Pusev. 
