Reports and Proceedings — Geologlcal Society. 571 
temperature that could be produced on Mallet’s bypothesis. He 
calculates that a mass 100 square miles in area, sinking 1 metre, on 
the assumption that half the heat developed was produced by 
friction, and that its effect extended to a distance of one metre on 
each side of the surface of rupture, could not produce along this 
surface a rise in temperature of more than 54-7° Centigrade. 
In Appendix II. (pp. 20-24) he cites many observations which 
show that inolten metals contain considerable quantities of different 
gases, and disengage them in cooling and solidifyiug. 
In Appendix IJI. (pp. 24-26) he shows that on the supposition 
of a large number of assumptions the amount of gas developed from 
the earth would be more than sufficient to account for the volcanic 
activity we see. His assumptions are, Poisson’s calculation of the 
heat lost annually by radiation : that the additional amount lost by 
hot springs, lava vents, etc., is one-tenth more : that the latent heat 
of consolidation is that of iron (which he estimates ingeniously) : 
that the molten materials at great depths disengage in solidifying 50 
times their volume of gas : and that the velocity of eruption of gas 
from a volcanic vent is fifteen metres per second. His result is that 
the gas disengaged would be sufficient to keep in vigorous activity 
20,000 volcanic vents, each one square metre in area. 
Though the author’s tlieory is open to some of the objections 
which he urges against other hypotheses, and though his calcula- 
tions, as is apt to be the case with such estimates, are of little im- 
portance, yet it does seem likely to be a partial cause of terrestrial 
volcanic activity, perhaps the whole cause of solar eruptions ; and 
the paper, as a clear Statement of the theory, is a valuable one. 
E. H. 
REPORTS -A-ZCsTID IFIROCIEIEIDIlsra-S. 
I. — Geological Society of London. — November 7th, 1877. — 
Prof. P. Martin Duncan, M.B., F.K.S., President, in the Chair. 
The President announced that Mr. Frederick L. Woodward had 
been appointed Junior Assistant in the Library and Museum. 
The following Communications were read : — 
1. A letter dated Foreign Office, September 14, 1877. 
“ Sir, — I am directed by the Earl of Derby to state to you, for the 
Information of the Geological Society, that his Lordship lias received 
a despatch from Her Majesty’s Minister at Teheran, reporting that 
a mining engineer had arrived there from Berlin, who, at the re- 
quest of the Persian Government, had been selected by Messrs. 
Siemens to ascertain what foundation there was for the reported 
existence of a rieh vein of gold in the vicinity of Zengan ; that he 
had visited the locality, and reported that auriferous quartz does 
exist, but that he had not yet succeeded in finding any vein or de- 
posit of the metal. — I am, Sir, your most obedient, humble Servant, 
“The Secretarv, Geological Society, etc. Julian Pauncefote.” 
2. “ Notes on Fossil Plants discovered in Grinnell Land by Capt. 
H. W. Feilden, Naturalist to the English North Polar Expedition.” 
By Prof. Oswald Heer, F.M.G.S. 
