522 Dr, Kidd’s OUefvatiom respecting 
shreds slowly subsided in the muriatic solution, derived pro- 
bably from the membranous part of the shelly matter of the 
limestone; for this insoluble residuum, when thrown into red- 
hot nitre, slightly deflagrated, and gave out an odour resem- 
bling burnt bones ; and as this residuum had been collected 
without the use of a filter, the inflammable matter could not 
well have been derived from any other source than the stone 
itself. 
The muriatic solution contained a small proportion of iron, 
and gave a very slight trace of magnesia. So that the com- 
position of the stone may be thus stated. 
Carbonate of lime _ - - - ^6 
Oxide of iron, sand, ochry clay, and animal membrane 4 
100 
In offering the following imperfect analysis of the saltpetre 
produced in the situations above alluded to, it is necessary to 
state, that the quantities on which I have hitherto had it in my 
power to operate have been very small. 
Some preliminary experiments made on a solution of salt- 
petre which had been formed during the summer, gave the 
following results. 
The solution contained no disengaged acid or alkali ; and 
upon the addition of oxalate of ammonia afforded the slightest 
possible evidence of the presence of lime. It contained minute 
portions of sulphuric and muriatic acid. A portion of it being 
evaporated left a mass of crystals -which, in their form, as in 
all their other characters, exhibited the properties of nitrate of 
potash. 
As it is usually stated by writers who speak of the subject. 
