Analysis of Shells. 365 
One hundred grains of oyster shell will therefore give, 
Carbonate of lime, - - - - - 95.18 
Phosphate of lime, - - - - - 1.88 
Silex, - - - - - - - 0.40 
Water, - - - - eR N= - 1.62 
Insoluble animal matter, - - - - 0.45 
Loss, &c. - - - - - - 0.46 
100.00 
As the quantity of carbonate of lime above stated was estimated 
by deducting the ascertained amount of certain ingredients, it was 
deemed important to verify the calculation by a direct determination 
of the proportion of the carbonate. Accordingly 100 grs. of shell 
were treated with muriatic acid,—filtered and then supersaturated 
with ammonia to precipitate the phosphate of line. ‘The liquid fil- 
tered from the phosphate was then acted on by oxalic acid and the 
oxalate of lime as before converted into carbonate. ‘The carbonate 
when dried agreed in weight very closely with the computed number, 
being very slightly more than 95.18 grains. 
The oyster shell is therefore a carbonate of lime, nearly in a state 
of purity, and it isin this light that it should claim attention either in 
agriculture or medicine. 
The scollop shells (Pecten Jeffersonius and P. Madisonius) of the 
marle beds of the southern states of which I have recently analyzed 
several specimens, yield a larger proportion of animal matter than 
the recent oyster shell, and indeed in many instances these shells 
would seem to have sustained no loss of this or in fact of any of 
their original constituents. 
The large variety of coral (Astrea) which belongs to the same 
marl, contains a very minute proportion of animal matter, and nearly 
the same per centage of phosphate of lime, as the oyster shell. 
Further observations upon the chemical structure, of our living 
and fossil shells I reserve for a future communication. 
