Mr. Fox's Experiments on Subterranean Electricity. 491 



prostration, and the general character of the prostrating force 

 which these may conjointly indicate. The course of induc- 

 tion suggested in my two papers on the tornadoes of Provi- 

 dence and New Brunswick, as taken together, are believed to 

 afford sufficient grounds for a correct determination, when 

 applied to the traces of other tornadoes. It is also satisfac- 

 tory to find, that in the surveys exhibited in the above cases 

 there are several traces of individual objects moving in the 

 tornado, which fully confirm the accuracy of the more general 

 induction. 



As regards Dr. Hare's own views of the electrical origin of 

 storms, some notice has been taken of these in Silliman's 

 Journal for October 1842, p. 261-263. Since the discoveries 

 of Franklin, an electrical origin and character has often been 

 conjecturally ascribed to storms. A want of originality in 

 advancing this hypothesis will not weaken any evidence which 

 shall be adduced in its favour; but until it shall have been 

 satisfactorily supported by observed phamomena, it will pro- 

 bably continue to be rejected by scientific inquirers. And were 

 it possible to show an electrical origin in great storms and 

 tornadoes, it would in no wise alter the known fact that a de- 

 terminate rotative action has been noticed in these storms. 



LX. Notice of some Experiments on Subterranean Electri- 

 city made in Pennance Mine, near Falmouth. By R. W. 

 Fox, Esq.* 



I HAVE already communicated to the Geological Society of 

 London t some results produced by the electric action of 

 two nearly east and west metalliferous veins which have been 

 partially explored in Pennance mine. I have since made other 

 experiments in the same mine, in which ore-points, consisting 

 of copper and iron pyrites in the two veins, were connected by 

 a pair of copper wires, which in most instances acted on a 

 galvanometer or other apparatus at the surface, an end of each 

 wire having been brought up through a shaft for the purpose; 

 about 50 fathoms of wire were employed, although the ore- 

 points in the different veins were only about 14 to 18 fathoms 

 asunder in a direct line. 



A galvanometer of not much sensibility was generally used ; 

 the needle, which was 2| inches long, moved on a pivot, and 

 had a coil of fine wire passed 48 times round it. Another 

 galvanometer, consisting of a suspended astatic needle and 140 

 coils of wire, was also employed occasionally. 



* From the Transactions of the Royal Cornwall Polytechnic Society. 



f The communication here alluded to will be found in our report of 

 the proceedings of the Geological Society, pres. vol. p. 457. — Edit. 



