Miscdlmu9us Localities of Minerals. 247 



wards the angle formed by this side, and one side of the ter- 

 minating pyramid. What adds to the interest of the speci- 

 men is, that by carefully inclining the crystal, so as to make 

 the enclosed bubble of air approach the angle, the property 

 of double refraction is distinctly seen, and we have present- 

 ed to us two bubbles instead of one. By an attentive ex- 

 amination of specimens in my possession, I had the good for- 

 tune to find several pieces, most of which contain one each, 

 and several three globules. Mr. Mason has since found 

 other similar specimens among those belonging to the 

 above named society, and among some in his own collection. 

 One of these has an undulating motion, rising in about the 

 centre of the cavity, so as to form a curve, and again de- 

 scending on the other side ; resembling in its movement, that 

 <jf a boat over a wave. One in my possession, instead of 

 passing backwards and forwards, will, when the crystal is 

 kept revolving, describe a trapezium ; two others per- 

 form circuitous courses ; in one crystal there are two cavi- 

 ties parallel to each other, containing globules that move 

 simultaneously in the same direction. With but one excep- 

 tion, none of the cavities hitherto noticed, are straight, 

 which renders it necessary to change a little the position of 

 the crystal, in order to facilitate the passage of the liquid. 

 Most of these specimens have been found among such as 

 were rejected on account of being too pale for good cabinet'- 

 specimens, which will therefore enhance the value of many, 

 that have heretofore been considered as uninterestingp 

 Some of these present every appearance of containing glos 

 bules ; but they are not moveable, in any position of the 

 specimen. One of these apparent globules, is so situated 

 as to exhibit the refractive power of the amethyst, equally 

 well as the one first noticed. 



Crystals of quartz, containing similar globules, are occa- 

 sionally found at Cape Diamond, near Quebec, which locali- 

 ty I b'^lieve has never yet been mentioned. 



It is probable that such specimens occur more frequently 

 than is generally supposed, and our ignorance of their exist- 

 ence may be fairly imputed, in part at least, to our not ex- 

 amining specimens from different localities, with that cau- 

 tion which we should ; for many of them are so placed, that 



