Sohibility of Phosphatic Materials. 
Ill 
lion more espcci;illy to the circumstances which affect the solu- 
bility of bones, 1 shall have occasion to offer some remarks on 
t\\v. relative efficacy of the various forms in which bone manures 
are presented to the notice of the agriculturist. 
Solubility of jmre tribasic Phosphate of Lime (Bone-earth) in ; 
distilled IVatcr. 
In the first place, tribasic phosphate of lime, artificially pre- 
pared, was chosen for experiment. Its preparation was simply 
effected by pouring a neutral solution of chloride of calcium into 
a solution of ordinary phos})hate of soda, taking care not to com- 
pletely precipitate the soluble phosphate contained in the latter. 
The precipitate produced under these conditions was washed 
until a drop of the washings was not rendered in the slightest 
degree turbid by nitrate of silver. 
Dried and heated, it is a compound consisting of three 
c(|uivalents of lime and one equivalent of phosphoric acid — 
hence its name, tribasic phosphate of lime. 
100 parts contain : — 
Lime (3 CaO) 54-19 
Phosphoric acid (P 0,) 45-81 
100-00 
Some of the precipitated pure phosphate of lime was left in a 
moist gelatinous condition and in that state its solubility in water 
was tested. 
The remainder was burnt and afterwards fin^ely ground. 
In each case a considerable excess of the gelatinous and moist 
precipitated phosphate of lime and of the finely-powdered and 
burnt phosphate was mixed with about half a gallon of cold 
and distilled water, repeatedly shaken up from time to time, 
and left in contact Avith the water for a week. The clear liquid 
resting on the undissolved phosphate of lime was then drawn off 
with a syphon and filtered perfectly clear through fine filtering- 
paper. A pint of the clear solution was then evaporated to 
dryness, and the heated residue finally weighed. In each case 
two pints of liquid were evaporated separately, and the following 
results obtained : — 
Amount of Phosphate of Lime (3 CaO, PO5) dissolved in 
Pure tribasic phosphate of lime, pre- 
cipitated, burnt and finely ground 
Pure tribasic phosphate of lime, pre- 
cipitated, and still moist 
VOL. IV. — S. 
1 Pint. 
Per Gallon. 
Graius. 
Giainb. 
1st Experiment 
-28 .. 
.. 2-24 
2nd 
•27 . 
.. 2^16 
Mean 
-275 . 
.. 2-20 
1st Experiment 
-72 . 
.. 5-76 
2nd „ 
•67 . 
.. 5-36 
Mean 
-695 .. 
... 5-56 
