British Association for the Advancement of Science. 47 



Durham, and found a slight electric action in lead veins running 

 east and west, other veins crossing these at right angles : in Gold- 

 bury mine he found it very trifling in lead veins occurring in sand- 

 stone. Indeed, he had generally observed, that the electric action 

 was much more feeble in veins situated in sandstone and lime- 

 stone than in those placed in granite and killas. He remarked a 

 singular phenomenon in a coal-mine at Gockfield Fell : — It is well 

 known, that coal is a bad conductor, but cinders the reverse ; and 

 in this mine he found an altered coal, resembling a cinder, which 

 would not conduct at all ; but he was able to render it a good con- 

 ductor, by causing it to be heated. Mr. Pox then made some ob- 

 servations on the temperature of mines, and detailed some exper- 

 iments. He had observed, that adventitious circumstances had 

 the effect of reducing this temperature, so that experiments must 

 be made independent of accident. He had accordingly placed 

 one thermometer, in various mines, at a depth of three feet wi the 

 ground, and another upon the ground of the mine, and then 

 marked the degrees ; and he uniformly found a difference of one 

 or more degrees between the two instruments, the imbedded one 

 rising sometimes as high as 92°. Also, in a mine having an in- 

 clined lode, he placed on the floor of a horizontal gallery a pair of 

 thermometers, one instrument imbedded, the other not, and found 

 that, at a distance from the lode of twenty-four fathoms, the deep 

 one marked 85g°, and the other 84° ; at ten fathoms off the lode 

 they were respectively 86J° and 85° ; in the lode itself, and upon 

 it, 92° and 88°. Mr. Fox found the increase of temperature vary 

 in different mines, and also in the rocks themselves, which he as- 

 cribed to the percolating water — killas being more porous, becom- 

 ing sooner heated by water filtering through, than granite, which 

 is more compact. 



North American Antiquities. — Dr. Warren, of Boston, U. S., 

 then offered remarks ' On some Crania found in the Ancient 

 Mounds in North America.' Whatever related, he observed, to 

 the lost nations of North America is interesting. The fate of a 

 people which occupied the richest part of that country, for an ex- 

 tent of more than a thousand miles, is involved in the deepest 

 obscurity. Nothing remains of their history, and we can gather 

 no ideas of what they were and what they did but from the con- 

 structions existing in the territory they inhabited. These works 

 are numerous, and scattered ovei; the country, from the lakes of 



