Chap. 4.] Moft Mineral Bodies cryftallized. 23 



It would perhaps be no rafh affertion to fay, that 

 the whole mineral kingdom appears in a cryftallized 

 ftate ; and this adds greatly to [the probability that 

 chemical combination or affinity is the great principle 

 which has acted in the formation of all bodies. The 

 caufes of this peculiar diftribution of parts are not to 

 be demonftrated, and on fo abftrufe a fubjecl, all that 

 we are able to perform is to produce fome probable 

 conjectures. 



The old and fanciful chemifts and alchemifts, who 

 remarked the curious figures which faline fubftances 

 affumed during their cryftallization, imagined that the 

 falts ftill retained the vegetative powers of the plants 

 from which they were produced, and even thought 



the water will take up no more faltpetre, then he may conclude 



* that it is faturated : let it fland without being ftirred, till it 

 ' grows cold. As it cools, a great many cryftals, all of the fame 

 ' fhape, may be feen {hooting out from the fides and bottom of 



* the bafon, and increafing in fize tiil the folution becomes quite 

 ' cold. When no more cryftals can be formed by that degree of 

 ' cold which prevails in the apartment where the experiment is 



* made, pour the liquor from the folid cryftals ; this liquor is ftill 

 faturated with faltpetre; and in order to make it part with more 

 ' of its faltpetre, fome of the water which keeps it diflblved mufl 

 ' be evaporated : upon the taking away a part of the water, a 



* correfpondent part of the faltpetre lofes the power by which it 

 ' is fufpended, and ought, upon that prefumption, inftantly to fall 

 ' to the bottom : yet it muft be remembered, that the water from 

 ' its increafed heat during the evaporation, is able to fupport 

 ' more faltpetre than if it was co)d; and therefore the faltpetre 

 ' will not begin to cryftallize, notwithftanding the lofs of part of 

 ' its menilruum, till the remainder begins to cool. By repetition 

 of this procefs of evaporation and cryftallization, we may obtain 

 < all the faltpetre which was at firft diffolved, as. no portion of it 

 ' can be evaporated with that degree of heat which is ufed in 

 4 . evaporating the water.' 



Watfou's Chem. Eff. p. 90 to 92. 



C 4 they 



