298 CHEMICAL AN ALTS IS oj an 



deficient in tranfparency, which adled flrongly on the cru- 

 cible. 



In temperatures fufficiently high, it lofes from 4-^ to 5 per 

 cent, of its weight ; but to produce this eftedl, the heat mufl be 

 equal at leaf): to 20° or 25° of Wedgwood. Part of the volatile 

 matter thus driven off is carbonic acid ; for the zeolite, when 

 reduced to powder, and mixed with acids, produces a flight ef- 

 fervefcencc. I found, by three different experiments, that the 

 lofs of weight after the efFervefcence was about 3 per cent. ; con- 

 fequently, the remaining 2, or 2- parts, may be prefumed to 

 confifl of moiflure. 



This fubftance produces a jelly, as moft other zeolites do, 

 with the ftronger acids. When ground to powder, and mixed 

 with the fulphuric, nitric, or muriatic acid, the mixture becomes 

 a firm jelly in a few minutes, provided the acids are not much 

 diluted, or ufed in too great quantity. That which is formed 

 by the a<5tion of the nitric or the muriatic acid, is nearly tranf- 

 parent ; but the ftone contains fo much lime, as will prefently 

 be fliown, that with the fulphuric, the jelly is white and opake, 

 on accovmt of the fulphat of lime which is generated. 



The prehnite in which it was inclofed, as already mentioned, 

 is of a light green colour, with fome luftre, and a confiderable 

 degree of tranfparency. It gives fire with fteel, can be readily 

 melted with the blowpipe, and froaths up much before fufion. 



Having made thefe preliminary experiments refpecfling the 

 general properties of the zeolite, I fubjedled a portion of it in 

 the next place to analyfis, to afcertain of what earths it was com- 

 pofed, and found that it confifted almofl wholly of filex and 

 lime, vi-ith a certain proportion of foda. The following were 

 the methods by which it was analyzed. 



I. One hundred grains, reduced to fine powder in a mortar 

 of flint, were mixed with 500 grains of muriatic acid, and 1000 



grains 



