Ill. Of the Frexipizity of the BraziL1AN Stone. By 
James Hutton, M.D. F.R.S. Epin. and Member of 
the Royal Academy of Agriculture at PaRIs. 
[Read Feb. 7. 1791+] 
O quality is more inconfiftent with the character of a ftone 
than flexibility. A flexible ftone, therefore, prefents an 
idea which naturally ftrikes us with furprife. For though 
among mineral bodies, we find flexible fubftances of the ftony 
kind, fuch as mica, mountain leather, and amianthus, thefe 
minerals owe their flexibility, either to their thinnefs, or to the 
fibrous ftru@ure of their parts. Therefore, when a ftone of 
any confiderable thicknefs is faid to have flexibility, we are led 
to think that here is fomething very extraordinary ; and we with 
to know upon what depends that quality, nowife proper to a 
ftone. 
Sucu, however, is the ftone from Brazil, of which the Baron 
de Dizrricu read a defcription in the Royal Academy of 
Sciences, in January 1784. There is alfo at prefent, in the pof- 
feffion of Lord GARDENSTON, a fpecimen of ftone, which 
correfponds with that defcription, inferted in the Journal de 
Phyfique for the year 1784*. The length of the {tone which I 
have examined is twelve inches, the breadth about five, and 
the thicknefs half an inch. When this ftone is fupported by 
. the 
* Tom. xxiv. p. 275, 276. 
