Hunt.) 250 [November 6, 
Mr. Brigham said that the last regular eruption of Mauna 
Loa was in 1868, while that described by Dr. Kneeland seems 
to be merely a temporary activity, which, however, it is pos- 
sible may burst forth with much greater violence. He then 
described the usual condition of the crater which’he had vyis- 
ited with the late Mr. Horace Mann. Mr. Brigham remarked 
that it was very difficult to account for the jet of lava de- 
scribed by Dr. Kneeland, for while the fountains hitherto ob- 
served have been situated below some basin of molten lava, 
upon which their existence evidently depended, this fountain 
was at the summit of the mountain. 
Dr. T. Sterry Hunt spoke of the various theories which 
had been proposed to account for the phenomena of volea- 
noes. 
After alluding to the now discarded chemical theory of Davy, he 
referred to that view which supposed a centre in igneous fusion, 
covered by a thin crust. This, for various reasons, is now rejected 
by the best physicists, who are led to regard the earth as having a 
crust of several hundred miles in thickness, if not indeed solid to the 
centre. To conciliate this condition of things with the phenomena 
of volcanic eruptions, the notion of a portion of the origina! igne- 
ous mass still remaining in a liquid condition between the solidified - 
centre and the crust, has been maintained by Hopkins and Scrope, 
but is far from satisfactory. There is, however, still another view 
which was put forward by Keferstein and by Sir John F. W. Hers- 
chel in 1834 and 1836, and for the past fourteen years had been re- 
peatedly set forth, explained and developed by the speaker. Accord- 
ing to this hypothesis the seat of volcanic activity is to be sought not 
in still uncongealed portions of the once liquid globe, but in deeply 
buried sedimentary strata, which, permeated by water and brought 
into a state of imneo-aqueous fusion, generate by the chemical reac- 
tions between their heterogeneous elements, both the gaseous and the 
liquid products of voleanoes, as well as the various plutonic rocks. 
This was maintained by Dr. Hunt in the Canadian Journal for May, 
1858, the Quar. Geol. Journal for November, 1859, in Silliman’s Jour- 
nal for May, 1861, and more recently in the Geological Magazine for 
June, 1869, in a paper “ On the Probable Seat of Volcanic Action.” 
In these various papers, and elsewhere, the relations apparent be- 
