92 The Production and Generation 

 nay, fometimes with pieces in them like water- 

 mts 9 which fcarce cohere in one fingle point, often 

 not at all. Upon the whole, all circumftances a- 

 gree, that neither an exhalation nor inhalation, but 

 ^ cryftallifation from waters, like the mooting of 

 falts or fugar, is the genuine, if not the only caufe 

 of rnountain-cryftals, and the like tranfparent, 

 variagated (tones. I (hall fay nothing of their 

 figures,, which, like common fait, are either cubi- 

 cal -, or like nitre, prifmatical -, or like tartarus 

 vitriolatuSy of irregular angles, and unequal fides, 

 commonly hexagonal : ncr mention, that an unfa- 

 line cryftal earrh, rho' not in fuch plenty as a fa- 

 line, is yet as intimately mixed in the water, nay, 

 in the fulled degree of clearnefs, pafles through 

 the clofeft drainers ; confcquencly, the cryftalhfa- 

 fation of fait is here not improperly alledged for a 

 model, or pattern. In fhort, the pyrites is a thing 

 that has grown, {till grows at this day, and will 

 continue to grow on druje, fo long As the interior 

 parts of this mafs of earch are fubjecl: 10 thofe mo- 

 tions and dhTolutions they hitnerto have undergone. 

 Here 'tis worth remarking, that the pyrites gene- 

 rally poflefs the eminences of the drufe, and often 

 their outmoft tacks or teeth, and that only with 

 one of their angles touching in the feweft points 

 ppflible, and not lying, but (landing thereon ; 

 (hewing that they were not there produced, but 

 conveyed thither from fome other quarter. 



I have had many famples of mixt-work 9 with 

 rents and breaks in the rock ; the former filled up 

 with, and the latter joined together again by py- 

 rites. Some drufe, or quartz, manifeft fuch cracks 

 and apertures, as plainly (hew they were formerly 

 entire, and afterwards burft or fprung afunder; 

 and in thefe fnTures the pyrites has been found in- 

 weathered, or lodged : fo that I know not whether 



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