u6 An ANALYSIS of 



Experiments to learn the quantity of the neutral fait s. 



The only ingredients of thefe waters, the quantity of which 

 had not yet been examined, were the neutral falts. The preli- 

 minary experiments, and the appearances obferved in the wa- 

 tery folutions of the extracts of thefe waters, gave me reafon 

 to be fatisfied, that thefe neutral falts were partly common fait 

 and partly Glauber's fait. To afcertain the quantities of them, 

 I made the following experiments : I had fome common fait, 

 which had been refined by a fecond cryftalization, and was in 

 folid dry and large cry Hals. Of this I weighed ten grains ex- 

 actly, which were diffolved in about half a pound of diftilled 

 water. I then added a folution of filver, which contained a 

 little fuperfluous acid. The filver w,as precipitated in the form 

 of luna cornea or argentum muriatum ; and I took care to add 

 rather more than the quantity which the ten grains of common 

 fait could precipitate. The luna cornea, after complete fubft- 

 dence, and decantation of the faline water from it, was care- 

 fully collected on a fmall filtre, and well warned with diftilled 

 water, and thoroughly dried and weighed. I thus learned, that 

 ioo parts of common fait are fufficient to give 235 of luna 

 cornea. This enabled me to learn, by fimilar experiments, how 

 much common fait is contained in the Iceland waters, and I 

 found that the quantity contained in 10,000 grains of Rykum water 

 was gr. 2.90, and in the fame quantity of the Geyzer water, I 

 found there was gr. 2. 46 of common fait. Some of my readers 

 may perhaps be inclined to fufpect, that the Glauber's fait 

 contained in the Iceland waters, might, by means of its vitriolic 

 acid, cotribute to the precipitation of a part of the filver ; but 

 experiments have fatisfied me, that a fmall quantity of vitriolic 

 acid, or of any vitriolic fait, dilTolved in a large quantity of 



water, 



