184 
Soluhility of Fliosphatic Materials. 
solved from ordinary bone-dust. The two samples of porous bone- 
dust, as miglit have been anticipated, were more soluble than ordi- 
nary dust ; and the sample of boiled bones, which it should be 
stated was reduced to a tolerably fine powder before being placed 
in water, was slightly more soluble than the two preceding samples. 
Boiled bones, or steamed bones as they may more appro- 
priately be called — ^for they are the refuse after the gelatine has 
been extracted from them by high-pressure steam — vary greatly in 
composition and in their solubility in water. In many instances 
this bone refuse yields phosphate of lime far less sparingly 
to water than good samples of common half-inch bones, from 
which the fat and but little of the nitrogenous organic constituents 
have been extracted by boiling. 
But although in the present instance boiled bones in the shape 
of glue-makers' refuse yielded more phosphate of lime to water 
than the other substances employed did, it must not be inferred 
that this refuse material always affords, with greater readiness, a 
supply of soluble phosphates to plants. 
The two samples of commercial bone-dust were both, as 
usual in the case of green or fresh bones, impregnated with 
grease, which in a great measure prevents their decomposition 
and their solution in water. 
Experiments loith hard Bonc-Dust. 
In the next place, I tried some experiments to test the solu- 
bility of bone-dust, m.ade from hard bones, containing but little 
fatty matter. 
The first sample was a specimen of very hard and fine dust ; 
the second sample was coarser ; and the third about as fine as 
the first, but made of bones not quite so solid. On analysis the 
third sample yielded the following results : — 
Composition of fine Bone-dust made due fly from hard solid Bone. 
Moisture .. .. lO-SO 
*Organic mattor 30-92 
Phosphati's of lime and magnesia (bonc-eartli) .. 5244 
Carbonate of lime 5'IG 
Alkaline salts -84 
Sand -28 
100-00 
*Containina: nitrogen .3-51 
Equal to ammonia 4* 56 
Separate portions of each of these three samples were placed 
in glass-stoppered Winchester quarts, and shaken repeatedly with 
distilled water, the proportions being 500 grains of bone-dust for 
every decigallon of water. The liquid was then allowed to 
settle, and alter 24 hours' standing it was drawn off and filtered 
