158 PICKERING. — LUNAR AND HAWAIIAN PHYSICAL FEATURES COMPARED. 
Of the three great Hawaiian representatives of the engulf ment type, Mokuaweoweo, 
the summit crater of Mauna Loa, Figure 9, and Kilauea, Figure 10, are coneless, while 
Haleakala, Figure 3, has in places a well-defined outer slope. This might lead us to 
suspect that it was of composite origin, an impression that is further confirmed by the 
fact that both its inner and outer slopes are made up in part of lava, and in part 
of scoria and sand. It seems to have originated partly by the engulfment process and 
partly by explosions of steam. 
No evidence of the great crater of Mokuaweoweo is to be seen until just before we 
reach its rim. It measures 3.7 by 1.7 miles in diameter, and is 300 to 400 feet in 
depth. It is composed of three confluent craters, of which the middle one is much 
gest. A portion of the 
shown in the figure, the view 
being taken in a direction nearly due south. The crater floor corresponds very 
closely in its nature to a lunar mare. 
Kilauea is much more accessible than Mokuaweoweo. Twenty-two miles in the 
train from Hilo, and nine miles by stage brings us to the Volcano House, situated 
upon its brink. Kilauea consists of a black lava plain measuring two mil 
bounded on all sides by precipices, often vertical, ranging from 200 to 500 feet 
in height. The view, Figure 10, was taken from its southeastern rim looking north. 
It is a curious fact that the black lava usually shows in the photographs to be much 
lighter colored than the gray cliffs surrounding it. Since the whole lava surface is 
very irregular, the fact that it is shiny and therefore bright in spots, cannot be given 
as an explanation of this fact. The surface is distinctly convex, d p. 171, as is the 
case with the smooth crater floors upon the Moon, and is not unlike in shape and 
curvature to the flattened summit of Mauna Loa, Figure 4. A in the section 
indicates the location of the Volcano House. The line B is on a level with it. The 
highest part of the floor is near Halemaumau, and in 1905 measured 230 feet above 
the edge where the Volcano House trail strikes it. The edge is 410 feet below 
the Volcano House at this point. 
Halemaumau, « the house of eternal fire," is situated three-quarters way across the 
— from the Volcano House. It is at present a nearly circular pit, 2,000 feet in 
d 
with practically vertical sides, and when the writer was there 
August its depth was estimated at 500 feet. Its floor consisted of a comparatively 
smooth lava surface, crossed here and there by narrow cracks, which at night showed 
bright red. That it was liquid only a few inches below the surface was shown by an 
occasional outbreak, when a flow of lava 5 to 10 feet broad by 20 to 50 feet in length 
would sluggishly stretch itself across the floor, glow for a few minutes, and then cool 
