go The Production and Generation 



when we confider the feeds of it may be conveyed 

 along with the water we ufe. 



'lis true, a very fmall matter of the tender ef- 

 fential fait of urine is incorporated in thefe fmall 

 Hones, as may be eafily obferved by its volatility, 

 and extraordinary agreeable fmell, upon ignition -> 

 yet fo incorporated, nay, fixed as it were, that 

 neither the tafte can perceive, nor hot boiling water 

 extract any of it. Moreover, it is impoffible to 

 exhibit either a faline, or other water, whether na- 

 tural or artificial, containing earth, that ever yield- 

 ed the like cryflals > all the vitriolic, aluminous, 

 nitrous, &c. waters, always mooting into their 

 own proper faline cryftals, be the time appropri- 

 ated for that purpofe never fo long ; yet, with this 

 remarkable difference, that the longer time they 

 take to moot, the cryftals prove much larger, 

 harder, more durable, and fo far approach nearer 

 to the nature of ftone ; but, in a pure, infipid, 

 earthy water, tho' ftanding never fo long, no ex- 

 periment to this purpofe is extant ; and indeed, 

 from waters entirely devoid of fait, no fuch thing 

 is to be expected, as they want the requifite cement 3 

 or interpofing fubftance. 



The fhiver- mines of Ilmenau in Franconia, af- 

 ford thofe well known bodies, called kidneys, of an 

 oblong oval figure, and enclofed in fhiver, as in a 

 fhell. In thefe we often find, together with the 

 figures of fifh, figured cavities, often containing a 

 clear water, bearing the impreffions of ears of corn, 

 fpray of the pine-tree, or rather, a kind of coral, 

 the circumference of which is fet round with fmall, 

 tranfparent, white ftones, like fugar-candy - 9 and 

 tho' thefe ftones may be eafily crufhed under the 

 teeth, yet, in the fire they lofe nothing of their 

 hardnefs or tranfparency. Now 'tis impoflible to 

 imagine thefe fmall ftones were originally created, 

 the circumftance of the water contained in the ca- 

 vities 



