107 
in the Cavities of Minerals. 
There is one geological relation, however, of the preceding 
facts, which may deserve some attention. Hitherto the con- 
tending theorists have limited their idolatry to two of the ele- 
ments ; but the existence of two new substances in minerals, one 
of which combines a great degree of fluidity with the high ex- 
pansive power of the gases, renders it probable, either that these 
substance existed at the formation of the globe, or that they are 
the result of laws of crystallographic combination which have 
escaped the notice of the philosophical geologist. Were such 
fluids the product of the ordinary processes of crystallization, 
they would occur in artificial as well as in natural crystals : and, 
consequently, while they remain undiscovered in the cavities of 
the first of these classes of bodies, we are entitled to attach a 
new difficulty to the aqueous hypothesis. 
Had the two new fluids occurred only in one mineral, or in 
minerals of a particular composition, they might have been sup- 
posed to have some relation to the elementary principles of the 
body, and to have arisen either from some accidental irregula- 
rity, which prevented them from crystallizing, or from the de- 
composition of the matter subsequently to its crystallization. 
The perfect identity, however, of the two fluids, as found in 
pure Quartz, in Amethyst, in Topaz, and in Cymophane,— 
minerals brought from the most opposite parts of the globe, — ■ 
from Scotland, Siberia, New Holland, Canada and Brasil, — 
establishes the universality of their existence, and adds to the 
probability of the supposition that they have performed some im- 
portant function in the organization of the mineral world. 
Art. XI . — Observations on the Natural History and Structure 
of the Aquatic Salamander, and on the Development of the 
Larva of these Animals from the Egg , up to the perfect Ani- 
mal, by Mauro BuscojNI, M. D. Member of various Socie- 
ties, and lately Lecturer on Physiology in Pavia *. 
In two former papers -J-, I communicated the substance of a me- 
moir on the Proteus Anguinus, by Professor Configliachi and Dr 
* Read before the Wernerian Natural History Society, April 4. 1823. 
Edin. Phil. Jouxn. vol. iv. p. 398,— and vol. v. p. 84. 
