190 BULLETIN OF THE BUSSEY INSTITUTION. 
that it is something which he would not naturally undertake, and which 
he cannot be expected to do as well as a trained artificer. It has been 
shown, moreover, by analysis of home-made superphosphates, that had 
been prepared from raw bones, that it is by no means an easy matter 
to obtain high-grade products by operating on that material. ‘There is, 
for that matter, good reason to doubt whether the old notion that the 
bones procurable at a farm should be treated with sulphuric acid can 
be justly commended. In the lack of facilities for reducing the bones 
to dust or meal, it is probably true as a general rule that they had 
better be decomposed by meaus of wood ashes ‘or some other alkali. 
It is now well known that raw bones are but slowly acted upon by 
sulphuric acid, unless, indeed, they are finely powdered, and in that 
event they had probably better be applied directly to the land, as bone- 
dust, in most instances. 
From what has been said already, it will be plain that the making of 
superphosphate at home, from a proper material, is really a valuable. 
resource to the farmer. He can in this way readily protect himself not 
only against actual fraud, but against the excessive prices which in this 
country are so often demanded by the makers and vendors of super- 
phosphates. Mr. Saltonstall’s results show clearly that while the prices 
of the raw materials remain as they are now, the farmer has it in his 
power to prepare his own superphosphate, from spent bone-black,* at 
a cost that is not only very much lower than the prices at which 
superphosphates have been commonly sold in our markets hitherto, but 
which is really and intrinsically small, as compared with the least pos- 
‘sible price. 
It is to be remembered, moreover, that in case the supply of bone- 
black should prove to be inadequate to any new demand that might 
arise, there would still be available, for the farmer’s purpose, those bet- 
ter kinds of phosphatic guanoes which are readily decomposed by 
sulphuric acid, as well as the bone-ash that is brought from South 
America. 
* To be obtained at sugar refineries, as well as of the dealers in fertilizers. 
