394 The Philippine Journal of Science 1914 
cept during rains, the ridges may rise as high as 150 meters. 
They are covered with ash and mud, although in many places 
the erosion has uncovered the original soil or has exposed layers 
of coarse cinders or rock. 
The active crater is in the center of the island. It is about 
2.3 kilometers long and 1.7 kilometers wide at the top. More 
than half of the bottom is occupied by a lake, whose elevation 
is about 2.5 meters above sea level, the same as that of the 
surrounding Lake Bombon. The water of the crater lake is 
clear, although dark colored, and salty. Its temperature de- 
creased from about 37° C. in October, 1913, to about 32° in 
April, 1914. Swimming in it, although much like salt water 
bathing, was of course more exciting. Very little steam, if any, 
arose from the lake in either October or December, 1913, but 
in April, 1914, some steam was noticed arising from a few 
places along the shore of the lake, as well as from small vents 
in the north crater wall, both inside and outside the crater. 
From certain points on the crater rim sulphurous odors are 
noticeable, but none were detected in the bottom of the crater. 
Steep precipitous walls formed the boundary of the crater on 
all sides. At the foot of the walls, especially on the east side, 
large quantities of ash and mud have been washed down and have 
accumulated. The crater rim is highest on the south and north 
sides with altitudes of 304 and 230 meters, respectively. Nearly 
all of the west side is low, the minimum elevation being about 
95 meters. There are other low points on the east side. 
Radiating from the crater rim are steep ridges. The slopes 
are about as steep as ashes can maintain. This is steeper than 
in sand dunes, on account of the adhesive properties of some of 
the constituents of the ash. At the corners of the island are 
peaks, which were former centers of eruptive activity, in the 
case of Mount Binintiang Malaki, as late as 1707. 
Previous to the eruption of 1911, the region outside of the 
crater was vegetated from the strand to the rim of the crater. 
The vegetation could all be summed up as trees, parang, grass- 
land, and culture in various combinations. Some trees over 
75 cm in diameter were present even on the crater slope. With- 
in the crater a tree of Ficus indica was present. A number 
of barrios were located along the shore, particularly in the north- 
ern part of the island and in their vicinity a number of cul- 
tivated plants are even yet to be found. 
During the eruption of 1911 the ground was entirely denuded 
of vegetation, virtually all of which was completely destroyed. 
