Penny Blood: Serial Sensation and Working-Class Entertainment — page 264: what you’re looking at

Machine-transcribed from the original scan — historical spelling and the odd misread are preserved.

cu. xx] THE VOLCANO IN ERUPTION. 247 communication with the same subterraneous reservoir’. The level of the lava in the crater which is in eruption will be raised above that in the other, because the column beneath it 1s rendered lighter by the expansion of the increased quantity of superheated water which is passing through jt at the time. The case will be somewhat like that of an inverted syphon, the Jiquid in one leg of which is lighter than that in the other. The explanation now offered for the elevation of the lava to the surface, differs from previous theories of the same kind, on account of the supply of water-substance being drawn from the entire liquid substratum, and not from the access of it to the lava at some point higher up. The importance of this dis- tinction appears from an objection made by Richthofen*. “It must here be remarked that some of the most eminent writers on the subject of volcanoes, chiefly Poulett Scrope, Prof. Dana and others, have suggested long ago, that the ascent of lava in a volcanic channel must be due to both the fluidity and ex- pansion imparted to it by the globular state of the water which finds ingress to the channels of the lava and enters into its composition, They have anticipated; by this suggestion, in some measure, the results of experiment established by Daubrée. But the supposition was only made for the case of lava, and not for that of rocks which were ejected without volcanic action proper” (that is by massive, or fissure eruption). “Yet even in regard to volcanoes it did only explain the extension of lava to the surface from a place at a limited distance below it, and failed to give a clue to the manner in which the constant supply of matter to those places was kept up’*. Both of these objections appear to be met if the entire liquid substratum is laid under contribution for the supply of the water-substance which acts as the intermittent agent in raising the column to the surface. 1 Another explanation suggested has been that the craters, though contiguous, may be connected with different fissures. 2 ‘Natural system of Volcanic Rocks,” ‘‘Memoirs of the California Academy of Sciences.”’ Vol. I. Part 11. 1868, 3 Ibid. p. 54, note, COLA @ NOO (CO)