310 -The American Naturalist. [April, 
of the different elements (without separating the iron and 
aluminum): 
(1.) P,O,Fe,0,=p, P,0,=0,47p, Fe,0,—0,58p. 
(2.) P,O;(4§28!)=p, P,O,=0, 50p, (49262) =0,50 p. 
If the precipitation is somewhat voluminous, the elements 
are determined by separating the phosphoric acid by mol- 
ybdate of ammonia. The acetic liquid, from which phosphate 
of iron and aluminum has been removed, is diluted to 200 
cubic centimetres. Exactly the half is then taken to deter- 
mine the lime, the magnesia and the phosphoric acid; the 
other half is put in reserve to verify the result in case of need. 
The addition of oxalate of ammonia, neutral and pure, will 
determine the precipitation of lime, which is separated as ox- 
alate and is determined as caustic lime, carbonate or sulphate 
of lime. The filtered liquid, supersaturated with ammonia, 
is left in repose during 24 hours and gives a precipitate of am- 
moniomagnesium phosphate, of which the weight, after igni- 
tion, enables us to calculate the magnesia and a part of the 
phosphoric acid. : 
P,0,2MgO—p,, 2MgO=0,36p,, P,0,—0,64p, 
The rest of the phosphoric acid is precipitated in the final 
solution by the magnesia mixture, and is determined as 
P,O,2Mg0. 
Rapid Methods.—In the large series of modern and fossil 
bones which have been examined, it would have taken a long 
time and been, perhaps, without penefit to make the complete 
analysis. In most cases it is sufficient to make, along with 
the qualitative analysis, the exact determination of fluorine as 
fluosilicate of potassium and the rapid determination of phos- 
phorie acid by means of a standard solution of uranium. 
This operation is executed in the following manner: 2 grams 
of the ash are dissolved in hydrochloric acid, and the liquid is 
neutralized and the phosphate of iron or iron and aluminum 
separated as before described, of which we take 47 or 50 per 
cent. to represent the weight of the phosphoric acid. Almost 
