ON THE COMPOSITION OF ZEOLITE. {^S 



had the zeolite contained any lime, as the muriate of lime* 

 would not have been decomposed by the ig^nition. 



The remaining matter, from which this muriate of soda 

 had been extracted, was repeatedly digested with marine 

 acid, till alt that was soluble was dissolved. V^'hat remained 

 was silica, and, after being made-red hot, weighed 4*9 grains. 



Th^jnuriatic solution, which had been decanted oft" from 

 the silica, was exhaled to a dry state, and the matter left 

 made red hot. It was alumina. 



To discover whether any magnesia was contained among 

 this alumina, it was dissolved in sulphuric acid, the solution 

 evaporated to a dry state, and ignited. Water did extract 

 some saline matter from this ignited alumina, but it had 

 not at all the appearance of sulphate of magnesia, a«td 

 proved to be some sulphate of alumina, which iiad escaped 

 decomposition, for on an addition of sulphate of ammonia 

 to it, it produced crystals of compound sulphate of alumi- 

 na and ammonia, in regular octahedrons. 



This alum and alumina were again mixed and digested 

 in ammonia, and the whole dried and made red hot. The 

 alumina left weighed 3*1 grains. 



Being suspected to contain still some sulphuric acid, this 

 alumina was dissolved in nitric acid, and an excess of ace- 

 tate of barytes added. A precipitate of sulphate of barytes 

 fell, which after being edulcorated and made red hot, 

 weighed l*2 grains. If we admit i of sulphate of barytes to 

 be sulphuric acid, the quantity of the alumina will be 

 — 3*1 — 0-4 = 2*7 grains. 



From the experiments of Dr. Marcetf, it appears, that 

 3*15 grains of muriate of soda afford 1*7 grain of soda. 



Hence, according to the foregoing experiments, the 10 jf- component 

 grains of zeolite analysed consisted of parts. 



Silica ' 4-90 



Alumina .,....» •••'♦j 2*70 



Soda ,..,...,.,,,.,.; 1-70 



Ice .... ♦ '. 0-95 



10-25 



♦ These names are retained for the present, as being familiar, thoug h 

 since Mr. Davy's important discovery of the nature ot wUat was calisd 

 oximiiriatxacid, the substances, to which they are aj^iJied, are l^nown not 

 to be salts, but metallic compounds analogous to oxides. 



♦ Phil. Trans. 1807 : or Journal, vol. XX, p, SO. 



