Solabilitij of Phosphatic Materials. 
195 
ally wlien tliey arc hard and crystalline, are very little acte.l 
upon by water. 
8. For agricultural purposes, pliospliatic minerals as well as 
bone-ash should be treated with a cjuantity of sulphuric acid 
sufficient to convert the whole of the insoluble phosphates therein 
contained as completely as possible into soluble combinations. 
It is a waste of good raw material to leave much of tire in- 
soluble phosphates unacted upon by acid. 
9. Insoluble phosphates present in superphosphate, or similar 
artificial manure, have little or no practical value to the farmer. 
10. The different kinds of bone-dust vary much in their 
solubility and practical efficacy as manures. 
11. Bone-dust made from solid bones, even when reduced to a 
fine powder, is less soluble in water and acts more slowly on 
vegetation than much coarser bone-dust made from porous or 
spongy bones. 
12. Fresh bones impregnated with grease do not readily enter 
into decomposition, and are less valuable as a manure than bones 
from which most of tlie fat has been removed by boiling in an 
open copper. 
13. Fat or bone-grease has no fertilising value whatever, and 
as it retards the solution of bone-dust in water, it is decidedly an 
objectionable constituent of fresh bones, as far as the agriculturist 
is concerned. 
14. Water dissolves much more phosphate of lime from rotten 
than from fresh bones. 
15. During the putrefaction of bones, soluble nitrogenous 
organic compounds and ammoniacal salts are produced from the 
gelatine contained in bones. These compounds act power- 
fully and quickly as fertilising constituents, and are indirectly 
useful in greatly enhancing the solubility of bone-phosphates in 
water. 
16. Bone-dust kept in a heap for a period of 3 or 4 months, 
heats and becomes more efficacious as a manure than bone-dust 
applied to the land fresh from the mill. 
17. Ivory-dust (or bone-shavings) is frequently adulterated with 
gypsum, fine sand, or vegetable ivory, but when genuine is the 
best form in which bone can be used for the production of home- 
made superphosphate. 
18. High-pressure steam renders bones so brittle that they 
can be readily ground into a fine powder, which is readily 
assimilated by plants. 
19. Bone-meal prepared by high-pressure steam contains not 
much less nitrogen than ordinaiy bone-dust, and as a manure 
is far more efficacious and valuable than the latter. 
20. Placed in a heap with ashes or sand, and occasionally 
O 2 
