12 THE CANADIAN NATURALIST. [Vol. X. 



ON THE GASEOUS SUBSTANCES CONTAINED IN 

 THE SMOKY QUARTZ OF BRANCHVILLE', CONN. 



By Arthur W. Wright, Yale College .* 



The existence in quartz of numerous cavities containing a 

 liquid substance is a matter of familiar occurrence, and great 

 interest has attached to the investigation of the character of 

 these inclusions, xllthough 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 pre- 

 vented a direct examination of them. The quartz from Branch- 

 ville 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. f The fortunate circumstance, noticed 

 by him, that when exposed to a moderately high temperature it 

 decrepitates and is speedily resolved into small fragments, made 

 it possible to obtain with great ease and convenience enough of 

 the enclosed subst;mces for an extended examination. The 

 material employed was derived from the collection of minerals 

 from Branchville, of Professors Brush and Dana. 



The temperature required for the disintegration of the quartz 

 is much below that of red-heat, and the bursting of the solid 

 material is evidently due to the increased tension of the gas, as 

 it does not occur in those fragments which contain no cavities. 

 The first trials were made with glass vessels, but the sharp frag- 

 ments of the mineral were shot off with such violence as to destroy 

 them immediately. Recourse was therefore had to a porcelain 

 tube about one centimeter in diameter, glazed inside. This 

 was carefully cleaned with pure distilled water, one end stopped 

 with a plug cemented in, and the other provided with a perforated 

 brass cap, into which could be screwed a piece through which 

 passed a slender glass tube, the joint being rendered tight by a 

 thin washer of india-rubber or paper. The closed end of the tube 

 was filled for some 12 centimeters with pieces of clean glass rod, 



* Reprinted from the Amer. Journal of Science of March, 1881. 



f Dr. Hawes' interesting article is not reproduced here, as it would 

 he incomplete without the illustrations. 



