3 1 8 Elements of Mineralogy. 



viates in hot water, what remains undiffolved 

 is filex ; to the folution he adds a cauftic vo- 

 latil alkali, which precipitates the iron and 

 argill, but keeps the zinc in folution, as it is 

 foluble in vitriolic ammoniac ; the precipitate 

 he re-diflblves in vitriolic acid, and feparates 

 the iron and argill as before. 



IV. VARIETY. 



Mixed with a notable proportion of Si/ex. 

 Zeolytiform. 



12. The real contents of this fubftance 

 were firft difcovered by Mr. Pellet ier, a moil 

 accurate Parifian chymift. It was long taken 

 for a zeolyte, being of a pearl colour, cryfta- 

 lized, femi-tranfparent, confifting of laminse, 

 diverging from different centers, and be- 

 coming gelatinous with acids. It was com- 

 monly called zeolyte of Friburgh, he found 

 loogr. of it to contain from 48 to 52 of 

 quartz, 36 of calx of zinc, and 8 or 1 2 of 

 water. 



SPECIES III. 

 Mineralized by the Vitriolic Acid. 



13. This has already been mentioned in 

 the fecond part. 



SPECIES 



