390 ESSAYS and OBSERVATIONS 



colour of the fait was owing, I believe, 

 to its having been a little fcorched at the 

 bottom of the glafs ; for, when I after- 

 wards gently exhaled the water before the 

 fire, the fait was of a pure white. 



15. A little of this fak put into a glafs 

 of water, made the water of a yellowifh 

 colour ; and, in a little time, it began to 

 feparate into fmall yellowifh coloured 

 iiakes, which, growing gradually larger 

 and thicker, precipitated ; after {landing 

 a night, the water was quite clear, with 

 a few detached fmall ll?ikes, floating 

 (clofe to the fides of the glafs ; the water 

 had the original taile of the fpavv, but 

 rather ftronger. 



I poured off the clear water, half into 

 pne glafs, and half into ano'iher : Into the 

 firft poured off, v.'hich was the cleareft, I 

 dropped fyrup of violets ; after flanding 

 a little, it gave a faint green tindlure : To 

 the other half, I added powder of galls; 

 jt flowly changed to a violet colour, then 

 to a purple, and, after (landing all night, 

 it was of a very dark blue, inclining to 

 black : Into the remaining water, with the 



fediment, 



