[ * 3 ° ] 
a folution of vitriolum Martis, when expofed for 
fome time to the air : and an infudon of iron in 
common water alfo emits a cremor of the fame kind. 
I remember, as I was once carefully obferving a large 
glafs full of a chalybeat water, which contained much 
of this cremor ; foon after it was expofed to the air, 
I obferved a tenuicus blueifh vapour riling in the 
parts of the water next the furface, which very much 
diminifhed its tranfparency ; and by degrees this va- 
pour was emitted by the lowed parts of the water : 
but as the cremor increafed on its furface, the water 
became gradually deprived of the blueifh tinCture, 
which it received from this halituous body ; which 
was apparently nothing elfe but the parts of the cre- 
mor feparating from the water, and afcending up- 
wards. From whence we may conclude, that this 
cremor confids of the very fined: parts of iron at- 
tenuated to the highed degree. 
It has been the opinion of mod naturalids, that 
thefe kind of mineral waters do abound in fulphure- 
ous parts. This they have conjectured from the 
foetor, that often attends them. But in what quan- 
tity or form thefe parts exid in the fluid, or by what 
means they can be rendered confpicuous, has not as 
yet been diffidently determined. Yet, I think, we 
may fufpeCt fome of the parts of this cremor to be 
fulphureous. They are volatile, and, being heated, 
do fly off from the pure metalline parts, which being 
more fixed, are thereby left deditute of thofe vivid 
colours, which they enjoyed from the fulphureous 
parts. Thefe are evident marks of fulphur, and are 
altogether analogous to fome other appearances of 
that mineral. Another obfervation tending to dip- 
port this is the want of thofe vivid colours in the 
cremor. 
