1895.] Fluorine as a Test for the Fossilization of Animal Bones. 455 
human bones in all deposits, for the different chemical com- 
positions of the deposits may produce differences in the com- 
position of the bones which will neutralize all our efforts in 
this direction. 
The incident at Billancourt affords an excellent illustration, 
Mons. Riviére, of Paris, sent to Mons. Carnot at the Ecole des 
Mines, two fragments of animal bones and one human tibia 
to be submitted to analysis (Bull. Soc. Anthrop., Paris: No. 6, 
15 July, 1893, Vol. 4, 4th Serie, page 309). The animal bones 
were white, friable and quite dense ; the human tibia was brown- 
ish-yellow, light and soft enough to crush under reasonable pres- 
sure. The ignition showed the following: In the animal bones, 
the organic matter was from 12.93 to 12.69 ; with the human tibia 
it was 19.65, and, therefore, the decomposition of the latter was 
much less than that of the first. The ash of the animal bone 
was a greenish-white; of the human, a bluish-gray attributa- 
ble probably to phosphate of iron. The determination of per- 
oxide of iron gave in effect 0.19 to 0.21 for the animal bone, 
and 3.06 for the human tibia. This difference gives a pre- 
sumption against the age of the two sets of bones being the 
same. The proportions of carbonate of lime differed slightly ; 
for carbonic acid, the animal bones gave from 6.06 to 4.75, 
while it was 6.15 in the human tibia. The determination of 
the phosphoric acid and fluorine were as follows: 
+ 
Long bones. 
Fossil animal. 
Scapula. 
Modern ? 
Human Tibia. 
m #2 | Fossil animal. 
as 
os 
t à 
w 
pP 
om s] 
IY 
Phosphoric acid | 
Fluorine { 
` 
= 
The phosphoric acid, then, had diminished more in the 
human bones than in the animal as though the latter had 
been more ancient. But the relationship between the phos- 
phoric acid and the fluorine is found as follows in the three 
cases : 
| 23,9 19,4 | 168,9 
