WATERS from ICELAND. . 123 
Aji de yak iN Gi Dye TX, 
In order to fhew, that fuch a fmall proportion of a vitriolic 
falt as is contained in the Iceland waters, has not the power to 
precipitate filver, I diflolved gr. 0.3 of exficcated Glauber’s falt, 
in gr. 2000 of diftilled water, which thus contained a propor- 
tion of Glauber’s falt rather greater than that contained in the 
Iceland waters. I then added five drops of purified aquafortis, 
and five drops of the folution of filver. The mixture remain- 
ed tranfparent feveral days. I afterwards added gr.o.7 more 
of the exficcated Glauber’s falt, without diminifhing in the 
leaft the tranfparency of the mixture. After a few days more, 
I added gr. 9 of the exficcated Glauber’s falt. This produced 
a diminution of tranfparency, and the fediment fubfided in a 
few days more. This fediment being carefully collected and 
dried, weighed gr. 0.3; but the clear liquor which had been 
filtrated from it, ftill retained the greater part of the filver. 
I therefore added to it fome pure common falt, which precipi- 
tated all the reft of the filver, and this laft precipitate, being 
alfo colleéted and dried, weighed juft one grain. 
Wuen I examined thefe two precipitates by means of the 
blowpipe, their qualities appeared to me fo much the fame, 
that I fufpect the firft was produced by a fmall quantity of 
common falt, contained imperceptibly in the Glauber’s falt. If 
there were 12 or 13 parts of common falt in roo0o of the 
Glauber’s falt, they were enough to produce the above quantity 
of the firft precipitate ; and as Glauber’s falt is prepared from 
common falt, we can eafily underftand how a {mall quantity of 
the common falt may remain in it. 
Q2 For 
