1895.] Fluorine as a Text for the Fossilization of Animal Bones. 307 
mains or fragments of two human skeletons. These human 
bones were transmitted to the museum with the suggestion 
that they belong to the same epoch and, consequently, were of 
the same antiquity as the deposit of Billancourt, although MM. 
Riviére and Gaudry, judging from the aspect, texture, density 
and, in fact, in all their physical characters, were of a contrary 
opinion. "This last proposition was combatted by several 
members of the Congress, and it was insisted that the human 
bones were contemporaneous with the ancient animal bones. 
These bones were afterwards, and for the purpose of settling or 
aiding at least in settling the disputed question, submitted to 
Mons. Carnot, who reported in his analysis that fluorine in the 
human tibia was but rvs of one per cent, while in the animal 
bones it was found in quantities of one per centand x. Mons. 
Carnot reports that, taking the average of the specimens, the 
presence of fluorine in the animal was from seven to nine 
times greater than that in the human skeleton, and that the 
human skeleton contains nothing or but slightly more than 
was to be found in modern bones; and his conclusion was that 
the human bones were much more recent. Mons. Carnot has 
given the results of his investigation, the manner of the con- 
duct of his experiments, his method of analysis, and his-opin- 
ion of the whole matter in a recent paper in the Annales des 
Mines, 2nd Bulletin of 1890, page 155. 
The remainder of this paper is, for the most part, a transla- 
tion of that of Mons. Carnot which, made by the present 
writer, has very kindly been revised for correction of chemical 
terms and formule by Prof. R. L. Packard. 
Process of Analysis pursued and recommended by M. Carnot.— 
Bones are composed partly of mineral and partly of organic 
matter. We are to deal only with the mineral, but must first 
determine the amount or proportion of the organic matter, and 
to this end the specimen to be operated upon is calcined at a 
moderate temperature, in such way as to preserve only the 
ashes or burnt bones. The caustic lime produced by calcina- 
tion is converted into carbonate of lime by the addition of car- 
bonate of ammonia, evaporation and calcination near 200 de- 
grees before weighing the ashes. By taking the weight of 
