Soluhilitij of Phosphatic Materials. 
185 
perfectly clear. A weighed quantity of the clear solution was 
acidulated with hydrochloric acid and evaporated to dryness in 
a waterbath ; the amount of nitrogen in the dry residue being 
subsc(|uently determined in the usual manner by a nitrogen com- 
bustion with soda-lime. When a watery solution of bone is 
boiled down to dryness some ammonia evaporates, especially 
when the bones are in a state of putrefaction ; for this reason a 
few drops of hydrochloric acid were added to the clear bone-solu- 
tion, and thereby the volatilization of any ammonia prevented. 
In another weighed quantity (generally 1 decigallon) of the 
clear bone-solutlon the phosphates were determined by first 
evaporating the solution to dryness, heating the residue in a 
platinum capsule, and proceeding further as before described. 
The bone-dust remaining undissolved was again shaken up 
with as much distilled water as was employed in making the first 
solution, it was then allowed to settle for 24 hours, and the filtered 
liquid was treated precisely in the same way as the first solution. 
In like manner a third solution was obtained from the same 
bone-dust which was employed for making the first. 
The object of these successive exhaustions with water was to 
ascertain if, with the removal of the more soluble nitrogenous 
constituents of bone, the solubility of the bone-phosphates re- 
mained the same or became less. 
In the first watery extract the proportion of nitrogenous organic 
constituents, as we shall see presently, was much more consider- 
able than in the liquids obtained by a second or third exhaustion 
with water, and as some organic matters appear to exercise a 
solvent action upon phosphate of lime, it was deemed desirable 
to try the effects of successive portions of water upon bone. 
Calculated per gallon the following results were obtained in 
the several experiments : — 
Table showing amount of Bone-phospliates and of Nitrogen = to Ammonia 
dissolved by 1 gallon of Distilled Water from hard Bone-dust, digested for 
24 hours in Cold Water, in the proportion of 500 grains to 1 decigallon 
of Water. 
Amount of Grains of 
Bone-phosphates. Nitrogen = Ammonia. 
[ 1st sokition .. MjS .... 9-10 = 11-05 
1, Very hard bone-dii.st .. < 2nd extraction 
I with water 
1-40 = 1-70 
Somewhat coarser bone- C 1st soUition .. 2-46 .... 13-26 = lG-11 
diistmadecbieflyfrom] 2ud extraction ) n , 1 ^ aq o cc 
solid bone .. ..( with water \^'^^ - - '^'^'^ = '^■'''^ 
jlstsokition .. 2-80 .... G-30 = 7-GC 
Fine bone-dust madel 2nd extraction 2-10 .... 2-10 = 2-55 
chiefly from solid bone] 3rd extraction 
\ -with water 
80 .. .. -70 = 
