198 
ANALYSIS OP A CALCULUS.' 
4. Water dissolves a minute quantity of the calculus. 
When the aqueous solution is evaporated nearly to 
dryness, mixed with a few drops of hydrochloric 
acid and bichloride of platinum, and then allowed to 
stand for a few minutes, a yellow ciystalline pre¬ 
cipitate forms, proving the presence of potash. 
[Note.]—The calculus did not contain any ammonia. 
The yellow potassium precipitate was collected on 
a filter, and the fluid which passed through the filter 
communicated a bright-yellow colour to the flame of 
the blowpipe, thus showing the presence of soda. 
5. llippimc acid was carefully tested for, but not detected. 
6. Carbonic acid was the only acid discovered. 
From the results of the qualitative analysis of the calculus, 
we evidently arrive at the conclusion that it consists of a 
mixture of the carbonates of lime, magnesia, potash, and 
soda, with organic matter. 
(3. (Quantitative. 
Three or four determinations were made of the amounts 
of lime, magnesia, and carbonic acid (the principal 
ingredients), contained in as many different fragments 
of the calculus, and in most cases the results differed 
considerably from each other, thus proving that the 
concretion did not possess a homogeneous composition. 
However, the following tabulated statement may be 
taken as representing correctly the average or mean 
proportional weights of the components contained in 
one hundred parts of the calculus : 
Carbonate of lime 
„ of magnesia 
Carbonates of potash and soda 
Organic matter 
Moisture 
5k32 
14-75 
traces 
28-2G 
2-67 
10000 
