178 
Solahilitij of Pliosphatic Materials. 
It will be seen that tribasic phosphate of lime in a j^elatinous 
and still moist condition is much more soluble than it is after 
being dried and burnt. In the latter condition, accordina; to 
these experiments, 1 part requires 31,818 parts of water to effect 
its solution, whilst in a gelatinous condition 1 part dissolves in 
14,388 parts of distilled water. 
Solubility of tribasic Phosphate of Magnesia in distilled Water. 
Phosphate of magnesia being a constituent of the bones of all 
animals, I tried some experiments with artificially prepared 
tribasic phosphate of magnesia, obtained by pouring a neutral 
solution of sulphate of magnesia into a solution of ordinary 
tribasic phosphate of soda, and thoroughly washing the pre- 
cipitated phosphate. 
In distilled water phosphate of magnesia is considerably more 
soluble than phosphate of lime, as will be seen by the fol- 
lowing determinations. 
Amount of Phosphate of Magnesia (3 MgO, 80^ dissolved hj 
finely ground 
Phosphate of magnesia in a 
condition 
: Piut of 
DistUled Water. 
Grains. 
Per Gallon. 
Grains. 
1st Experiment 
•87 . 
.. 6^9« 
2nd 
•89 . 
.. 7^12 
Mean .. .. 
•88 . 
.. 7^04 
1st Experiment 
1-78 . 
.. 14^24 
2nd 
1^80 . 
.. 14:^48 
Mean 
1-79 . 
14-36 
Here again we see that the precipitated and still moist phos- 
phate is much more soluble in water than that which had been 
burnt and ground. 
Solubility of Phosphate of Lime in Water containing 1 per cent, of 
Chloride of Ammonium {sal ammoniac'), and in solutions contain- 
ing 1 per cent, of Carbonate of Ammonia. 
A large excess of phosphate of lime was placed in a bottle 
and repeatedly shaken with a solution of chloride of ammonium. 
After a lapse of seven days the clear liquid was drawn from the 
undissolved phosphate of lime and filtered ; 1 pint was then 
evaporated to dryness and the residue heated ; the heated residue 
was dissolved in a few drops of hydrochloric acid, and the solution 
precipitated with ammonia ; the precipitate was washed with a 
little distilled water, and then dried, heated, and weighed, when 
the following results were obtained : — 
