3oo CHEMICAL ANALTSIS of an 



/lightly, and weighed 31^ grains. By treating it with fulphuric 

 acid, I detected fome flight traces of magnefia, the reft being 

 wholly converted into fulphate of lime. 



4. T1-1 e different earths having been thus feparated from the 

 -folution, it was evaporated to drynefs, for the purpofe of ob- 

 taining the foda, which I had learned by previous experiments 

 would be wholly taken up with the other foluble parts of the zeo- 

 lite, whendecompofed by acids. After the evaporation, a white 

 fait remained, which was heated gradually in a crucible to volati- 

 lize the muriate of ammonia, formed in the courfe of the ana- 

 lyfis. When white vapours ceafed to rife, the heat was increa- 

 fed to rednefs, and a fait was left which weighed 17 grains. 

 On re-diffolving it in a fmall quantity of water, and boiling the 

 folution with carbonate of ammonia, a minute portion of carbo- 

 nate of lime was precipitated, which weighed one grain ; equal to 

 about half a grain of pure lime. I obtained the fait by a fe- 

 cond evaporation ; and after it had been expofed again to a ve- 

 ry low red heat, it weighed 16 grains, and confifled wholly of 

 muriate of foda. 



According to Mr Kirwan's experiments, 16 parts of mu- 

 riate of foda in cryflals, contain 8.5 parts of foda; but the 16 

 parts above mentioned, by having been dried in a red heat, and 

 confequently freed from water of cryftallization, would con- 

 tain fomewhat more than 8.5 parts of foda. However, the pro- 

 portion of foda in 100 parts of the zeolite, may be ftated at 8.5 

 parts, which, though probably rather lefs than the real quan- 

 tity, muft be very nearly correct. 



Having finifhed the experiments juft defcribed, I analyzed 

 the zeolite a fecond time ; and made ufe of nitric acid, for the 

 purpofe of afcertaining whether any muriatic acid entered into 

 its compoiitio.n. By the tefl of nitrate of filver, I found that 



fome 



