180 
Solubility of Phosphatic Blaleiials. 
Amount of Phosphate of Lime dissoked hj Water containing 1 per cent, 
of Nitrate of Soda. 
. , ... . Calculated 
In 1 J'liit. p„ 
oiaiiis. 
I, ■•,,11 1 , pv ( 1st Experiment "87 .... 6'96 
1 rccipilalcd phosphate ot hnie ) ' g.gQ 
in moist coudition .. .. ( '[^ _ 6-88 
The material employed in this experiment was recently pre- 
pared and very bulky, and on this account dissolved rather 
more readily than the phosphate of lime of another preparation 
in the previous trial with distilled water. 
Making due allowance for the differences in the meclianical 
state of aggregation of the particles of the phosphate and the 
unavoidable errors which attach to all analytical determinations 
of that kind, I believe the results of the several determinations 
decidedly prove that neither common salt nor nitrate of soda 
increases the solubility of phosphate of lime in water. 
In the next place, I determined the amount of phosphate of 
lime which distilled water is capable of taking up from pure 
bone-ash, commercial South American bone-ash, coprolites, and 
a number of other phosphatic materials, mentioned in the sub- 
joined tabular statement of results. 
In operating upon phosphatic minerals, guanos, &c., it is not 
sufficient merely to evaporate the watery solution to dryness ; for, 
besides phosphates of lime, water dissolves more or less car- 
ijonate of lime, magnesia, and traces of alkalies, which, added to 
the weight of the phosphate of lime, in many instances would give 
quite erroneous results. By leaving an excess of the several 
materials in contact with water for a week, and subsequently filter- 
ing, a perfectly clear liquid was obtained in each case ; of this 
two pints were evaporated separately to dryness ; the residue was 
then dissolved in as little hydrochloric acid as possible, and the 
solution precipitated with ammonia ; in some instances the pre- 
cipitated phosphate was redissolved and thrown down a second 
time with ammonia, and, after washing witlr a little water, dried, 
burnt, and weighed. 
The pure bone-ash was made from the shank-bone of a horse ; 
and was washed with distilled water for a long time to free it 
from all saline matter contained in it before trying the solubility 
of the phosphate. Its composition in 100 parts was as fol- 
lows : — t 
