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 Cockfield 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. Fox 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 in the 
ground, and another wpon 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 854°, and the other 84°; at ten fathoms off the lode 
they were respectively 864° 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. me, Warren, of icicle, 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 over the country, from the lakes of 
