346 ESSAYS awn OBSERVATIONS 
a half; this I immediately poured into a China 
tea-cup, and, when cold, filtrated it: the fil- 
trated liquor was clear and limpid, and had a 
{trong chalybeate tafte; this was evaporated by 
a fand-heat, in a wide-mouthed glafs; there 
was left a falt of whitifh-brown colour, 
which had an aluminous and ftrong chaly- 
beate rough tafte. The whitifh-brown co- 
lour of the falt was owing, I believe, to its 
having been a little fcorched at the bottom 
of the glafs ; for, when I afterwards gently 
exhaled the water before the fire, the falt 
was of a pure white. 
15. A little of this falt put into a glafs of 
water, made the water of a yellowifh co- 
lour; and, in alittle time, it began to fepa- 
rate into {mall yellowifh coloured flakes, which 
growing gradually larger, and thicker, pre- 
cipitated ; after ftanding a night, the water 
was quite clear, with a few detached, {mall 
flakes, floating clofe to the fides of the glafs ; 
the water had the original tafte of the Spaw, 
but rather ftronger. 
I poured off the clear water, half into 
one glafs, and half into another: into the 
firft poured off, which was the cleareft, I . 
dropt fyrup of violets; after ftanding a little, 
it 
