I AR Ee eae ee Cr Cea eget, eee 
A. W. Wright—Gases in Smoky Quurtz. 209 
night the vibration of the two bubbles having the slower rates 
of motion had ceased. 
A specimen of granite containing very movable bubbles, 
included in water cavities, was likewise treated. In the morn- 
currents of heat, by producing alternations of evaporation and 
condensation, can cause motions like those seen in the bubbles 
floating in these fluids, and that the changes of temperature suf- 
ficient to move these bubbles are very small in amount, and 
very difficult to avoid. This explanation is not new, and 
would, I think, suggest itself to most physicists, but it has not 
been shown to be sufficiently probable to receive acceptation. 
result of my examination of the cavities in quartz from 
Branchville has been most plainly to identify these cavities as 
being of the same nature as those that have been studied by 
several eminent microscopists in topaz and other erystals, and 
In granites, gneisses, basalts and other rocks. Quantities of 
condensed gas sufficient for exhaustive analysis have not how- 
ever been heretofore found, and therefore the associated com- 
munication of Professor Wright will have a general interest to 
geologists, since it bears upon a class of long studied phe- 
nomena, 
— 
Art. XXV.—On the Gaseous Substances contained in the Smoky 
Quartz of Branchville, Conn.; by ArtHuR W. Wricut, Yale 
College. 
_ THE existence in quartz of numerous cavities containing a 
liquid substance is a matter of familiar occurrence, and great 
Mterest has attached to the investigation of the character of 
these inclusions. Although the presence of carbon dioxide 
and water had been well established, the difficulty of separating 
the contents of the cavities in sufficient quantity has hitherto 
tanchville is remarkable for the great size and number of 
the Cavities, the peculiar characteristics of which are described 
by Mr. Hawes in the preceding article. The fortunate circum- 
