Dr. Eajon on Cryftallization . 33 
in England, is better known by the name of 
Derbyfhire Spar. All the bodies belonging to 
this clafs have- lately been (hewn to confift of 
a calcareous earth, and an acid of a very peculiar 
nature, which has the property of corroding glafs, 
and of converting water into flint. Flint, there¬ 
fore, is probably not a Ample earth, as philofo- 
phers have generally fuppofed, but a compound 
fubltance, confiding of water, and this lately 
difcovered acid. 
The verifiable, or flinty earths, bear, never- 
thelefs, ftronger marks of a Ample fubftance, than 
any body hitherto known ; and we are now cer¬ 
tain, that it forms the bafis of rock cryftals, * 
and a part of the whole tribe of precious ftones 4 
except the diamond. All thefe (tones have 
evidently been formed by the cryftallization of 
the matters which enter into their compofition ; 
and all the phenomena relating to their figure. 
* II feroit d’ailleurs difficile de penetrer affiez profonde- 
ment dans le interieur du globe pour recueillei 4 de la terre pri¬ 
mitive, & qui n’auroit eprouv6 aucune alteration. 11 paroit 
certain, que fi Ton pouvoit fe procurer de cette efpece de 
terre, & un degre de feu fuffifant pour la faire entrer 
Cn fufion, on la reduiroit en une maffie auffi belle que Ie 
beau cryftal de roche, & qu’on ne pourroit dillinguer l’un 
de l’autre. 
Chymie Experimentale & Raifonnee, par 
Mr. Baume, Tom. I. p. 104. 
VOL. I. 
D 
tranf- 
