224 HAWAIIAN ISLANDS. 
our general remarks on these kinds of craters for the present, and con- 
sider in this place 
VII. The Origin of Kilauea and the Pit-Craters of Mount Loa.— 
Leaving out of view for the present Mokua-weo-weo, and counting 
from Kilauea, the pit-craters of Mount Loa are ten in number, within 
a distance of fourteen miles. Their several peculiarities, especially 
the abrupt walls free from scoria, favour the view that they are simply 
the results of subsidence. Yet it would be surprising that areas of 
subsidence, from undermining, should, in so great a number of in- 
stances, have a nearly circular form. Moreover, the absence of scoria 
from the walls is in fact no proof that they were not ance filled with 
lava; for there is the same absence of scoria from the walls of the 
lower pit of Kilauea, although the whole black ledge was covered 
before the eruption of 1840; and so perfectly clean are these bluff 
fronts, that the facts, were they not beyond doubt, would hardly be 
credited. ‘There is the same reason, therefore, for believing that the 
Javas never filled this lower pit, as that they never filled the whole 
crater of Kilauea, or any of the other pit-craters mentioned. 
We deem it more consonant with the mode of operation in these 
volcanic regions to suppose that all these pits were once boiling lakes, 
like those now in the bottom of Kilauea; and that, like the small 
cones, they occur upon former fissures, on this part of the dome; that 
they are the points in these fissures, where, after ejections from fissures 
had partially subsided, the lavas continued to boil up, and remained 
for a while in active ebullition. ‘The facts in Kilauea itself point to 
this conclusion. New pools are opened from time to time in this 
crater ; and the steps are the same as just pointed out,—a rending of 
the surface and an overflow, after which the wider part of the open- 
ing remains as an active boiling pool. Captain Chase witnessed the 
formation of one of these boiling lakes, and describes the fissures, suc- 
ceeded by a flood of lava, which soon became “a great lake of fire.” 
We perceive, moreover, that this is the natural course of things. 
Lavas do not melt their way to the surface; for if so active in any point 
as to threaten this result, their vapours will break the crust for their 
escape, and thus open the way for the outflow of the lava. After the 
opening is made, the constant ebullition of the lavas will necessarily 
give at last a circular form to the boiling pool, whatever the shape with 
which it commenced, unless action within the fissure on which it was 
formed, causes it to become oblong. We thus comprehend the very 
regular circular outline of some of these pits, and at the same time the 
