Solubility of Phosphatic Materials. 
179 
Amount deponiteil 
In 1 Tint. IVr (JiiUon. 
Grains. Grains. 
\ , fv { 1st Expcrimenl, 2-77 .... 22-lG 
PreciiMtai^^^^^ » 2-07 .... 21-36 
(3 CaO, rO,) still moist ..(^^^0 .. .. 2-72 .... 21-76 
In the presence of an ammonia salt, phosphate of lime thus 
becomes much more soluble than in pure water. 
The addition of 1 per cent, of sal ammoniac to the water em- 
ployed in the preceding experiments increased the solubility of 
phosphate of lime in distilled water nearly fourfold. 
Carbonate of ammonia likewise renders phosphate of lime 
more readily soluble than it is in pure water, but not to the 
same extent as sal ammoniac, as will be seen by the following 
results : — 
Amount of Phosphate of Lime dissolved by Water containing 1 per cent, 
of Carbonate of Ammonia. 
In 1 Knt. Per Gallon. 
Grains. Grains. 
I 1st Experiment 1-42 .... 11-36 
Precipitated phosphate of lime < 2nd „ 1-40 .... 11-20 
( Mean .. .. 1-41 .. .. 11-28 
In the next place, I have to record some experiments which 
have shown me that neither chloride of sodium nor nitrate of soda 
has any effect in materially increasing the solubility of pure 
phosphate of lime in water. 
Amount of Phosphate of Lime dissolved by Water containing 1 per cent, 
of Chloride of Sodium in solution. 
Calculated 
. In 1 Pint. per Gallon. 
Grains. Grains. 
!lst Experiment '52 .... 4-16 
2nd „ -55 .. .. 4-40 
3rd „ -58 .. .. 4-64 
4th „ -57 .. .. 4-56 
Mean .. ., -555 .... 4-44 
On comparing these results with those obtained by dissolving 
phosphate of lime in pure distilled water, it might appear that 
the presence of common salt had somewhat reduced the solu- 
bility of the precipitated phosphate of lime ; I do not, however, 
think this was really the case, for the precipitated phosphate used 
in the salt experiments had been kept longer and become less 
gelatinous and more dense than the specimen treated with distilled 
water, and direct experiments have shown me that this difference 
in the mechanical condition of the phosphate slightly affects its 
solubility in water. 
N 2 
