m the Cavities of Minerals, 29 



*- 



The residue of the first fluid is volatilized by heat ; and it 

 is also dissolved, but without effervescence, by the sulphuric, the 

 nitric, and the muriatic acids. After standing some time, both 

 these substances acquire a brilliant lustre, as if some metallic 

 body entered into their composition *. 



SECT. VII. On the Existence of Moveable Crystals in a Fluid 

 Cavity of Quartz. 



Although particles of opaque solid matter have been observed 

 in the cavities of crystals containing fluid, as will be described 

 in the next section, yet, so far as I can find, no crystallized 

 body, and, indeed, no matter capable of crystallization, has ever 

 been discovered in them. The quantities of saline impregna- 

 tion, indicated by a scarcely perceptible cloudiness in solutions 

 of silver and muriate of barytes, were so minute in Sir HUMPHRY 

 DAVY'S experiments, that he considered the water as nearly pure. 

 I was, therefore, in no small degree surprised, when I discover- 

 ed, in a cavity of a quartz crystal from Quebec, from the cabinet 

 of Mr ALLAN, not only insulated crystals, but a tolerably large 

 group, which were moveable through the fluid upon turning the 

 specimen f . The crystal was perfectly sound round the cavity, 



* In opened specimens, which had stood more than a month exposed to the air, 

 I observed small green spheres resting on the surface. They were soft and semi- 

 transparent, like green wax, and varied from j^th to 3 J r ,th of an inch in dia- 

 meter. They were not acted upon by any of the above mentioned acids, and were 

 therefore a distinct substance from that of the two new fluids. They occurred in no 

 fewer than 25 out of 40 crystals, three being sometimes found in one specimen ; 

 and there can he no doubt that they consisted of fluid matter which had oozed out 

 >f the crevices of the mineral. 



-f- There were also numerous opaque particles in the cavity, which descended 

 slowly in the fluid. 



