WATERS from ICELAND. 117 



water, does not precipitate filver * ; and to prevent any part of 

 the filver being precipitated by the alkali of the water. I added 

 of purified aquafortis, more than enough to faturate the alkali, 

 before I added the folution of filver. 



Another fet of experiments, on the fame plan, but made 

 with Glauber's fait and the folution of barytes, in place of com- 

 mon fait and folution of filver, enabled me to afcertain with equal 

 exactnefs the quantity of Glauber's fait contained in thefe waters. 

 I firit learned that if pure Glauber's fait be perfectly exficcated, by 

 evaporating the water that is in its crydals, 10 parts of this 

 exficcated fait are fufHcient to precipitate as much barytes, from 

 its folution in muriatic acid, as will form 17 of barytes vitrio- 

 lica. This fact being afcertained, I added fome of the diffolved 

 barytes, to feparate portions of the Iceland waters, fo long as 

 any muddinefs and precipitation was produced ; and I care- 

 fully collected, wafhed, dried and weighed the precipitates. 

 I thus learned, that the water of Rykum contains in gr. 10,000 

 of it, as much Glauber's fait as would give gr. 1.28 of exficcated 

 Glauber's fait, and the water of Geyzer as much as would give 

 gr. 1.46 f. 



In making thefe laft experiments alfo, I added fome purified 

 nitrical acid to the Iceland waters, to prevent any precipitation 

 of the barytes which might have been occafioned by the alkali 

 of the water. 



In reviewing the experiments I have now defcribed, if we 

 neglect the fmall quantity of fulphureous gas, the contents of ' 

 thefe waters will appear as follows : 



In 



See the appendix to this paper. 



\ The method by which thefe fmall quantities of fediments and precipitates were col- 

 lected and weighed, is explained in the appendix to this p<iper. 



