7 
Hunt.] 252 [November 20, 
ology, pp. 129, 130.] This view of Vose is confirmed by the late 
researches of Robert Mallet, communicated to the Royal Society of 
London in June, 1872, who concludes that ‘‘ as the solid crust sinks 
together to follow down the shrinking nucleus, the work expended in 
mutual crushing and dislocation of its parts is transformed into heat, 
by which at the places where the crushing sufficiently takes place 
the material of the rock so crushed, and that adjacent to it, are 
heated even to fusion. The presence of water at such points deter- 
mines volcanic eruption.” ‘This view of the source of heat is sup- 
ported by experiments on a large scale undertaken by Mallet. 
Dr. Hunt, while admitting mechanical pressure, as explained by 
Vose and Mallet, to be an important source of subterranean heat in 
the crushed and deeply buried strata, remarked, 
1st. That these, from their depth, are already at an elevated tem- 
perature, so that the heat thus developed comes in to supplement 
that derived by conduction from an igneous centre. 
2d. That it is the heat from this latter source, which, as he has en- 
deavored to show, by establishing lines of least resistance in the crust, 
localizes the effect of the contracting nucleus, and determines the 
region in which the folding and crushing of the crust, with attend- 
ant elevation of temperature, shall take place. 
3d. The seat of this process being in stratified sediments, which, 
besides water, include, in many cases, compounds of chlorine, sul- 
phur and carbon, the origin of the steam and the various gases which 
accompany volcanic eruptions, is explained without supposing an 
introduction of water to the fused mass from an exterior source. 
With the contributions of Vose and Mallet the theory of plutonic 
and volcanic action advocated by Keferstein, Herschel and the 
speaker, would seem to be well nigh complete. 
November 20, 1872. 
The President in the chair. Fifteen members present. 
Dr. Kneeland described a trout breeding establishment 
near Truckee, Cal., which he visited last June. He also gave 
a brief account of the fauna of the Sandwich Islands, which 
: 
