Geology and Geography. 361 



had detected in water taken from diflferent mines, and also taken 

 from parts of the same mine, seemed to indicate another probible 

 source of electricity ; for can it now be doubted, that rocks impreg- 

 nated with or holding in their minute fissures different kinds of 

 mineral waters, must be in different electrical conditions or rela- 

 tions to each other ? A general conclusion is, that in these fissures 

 metalliferous deposits will be determined according to their relative 

 electrical conditions ; and that the direction of those deposits must 

 hare been influenced by the direction of the magnetic meridian. 

 Thus we find the metallic deposits in most parts of the world ha- 

 ving a general tendency to an E. and W. or N. E. and S. W. bear- 

 ing. Mr Fox added, that it was a curious fact, that on submitting 

 the muriate of tin in solution to voltaic action, to the negative pole 

 of the battery, and another to the positive, a portion of the tin was 

 determined like the copper, the former in a metallic state, and the 

 latter in that of an oxide, shewing a remarkable analogy to the re- 

 lative position of tin and copper ore with respect to each other, as 

 they are found in mineral veins. 



Artificial Crystals and Minerals. — A. Crosse, Eso of Broomfield, 

 Somerset, then came forward, and stated, that he came to Bristol 

 to be a listener only, and with no idea he should be called upon to 

 address a section. He was no geologist, and but little of a mine- 

 ralogist ; he had, however, devoted much of his time to electricity, 

 and he had latterly been occupied in improvements in the voltaic 

 power, by which he had succeeded in keeping it in full force for 

 twelve months by water alone, rejecting acids entirely. Mr C. 

 then proceeded to state, that having observed in a cavern in the 

 Quantock Hills near his residence, that part of it which consisted of 

 slate was studded with crystals of arragonite, while the limestone 

 part was covered with crystals of calcareous spar^ he subjected por- 

 tions of each of these substances in water, to long continued galvanic 

 action (ten days action), and obtained from the slate crystals of arra- 

 gonite, from the limestone crystals of calcareous spar. In order 

 to ascertain if light had any influence in the process, he tried it 

 again in a dark cellar, and produced similar crystals in six days, 

 with one-fourth of the whole voltaic power. He had repeated the 

 experiments a hundred times, and always with the same results. He 

 was fully convinced that it was possible to make even diamonds, 

 and that at no distant period every kind of mineral would be formed 

 by the ingenuity of man. By variations of his experiments he 



