PAKT 4.] 
Ball: Barren Bland and NarJcondam. 
87 
side were, no doubt, blown off by a violent eruption, and tbe present cone was subsequently 
formed inside. 
For a long time Barren Island was considered by Yon Buch and others of his school 
as a most favourable example of his elevation theory of craters. 
The gap or fissure in the surrounding walls bears about north-west-by-west from 
the centre of the island. It is the only place where an entrance can be obtained to the central 
valley. 
Hot Spring .—Close to the landing place, there is a hot spring which has been mentioned 
in several of the accounts of the Island. Dr. Plaj’fair found the temperature to exceed 140°, 
—the limit of his thermometer. Dr. Liebig’s thermometer was only graduated up to 104°, 
but judging from the feel to the hands, he estimated it to be Bear the boiling point. The 
Andaman Committee record it at from 158° to 163°. At the time of our visit the highest 
temperature of the water where it bubbled out of the rocks, close to high watermark, was 
130° F. We failed to boil some eggs in it which we had brought with us for the purpose. 
The water is perfectly clean and sweet,* and there was no trace of sulphureous vapours. 
Strange to say, where, though mingled with the sea, it was still too hot for the hand to he 
retained in it with comfort, there were a number of brilliantly colored fish swimming about. 
Facing the landing place is the termination of a flow of lava which extends backwards 
from this for about a mile to the base of the cone, round which it laps for perhaps f of the 
circumference. The height or thickness of this flow of lava is about 10feet at first, gradually 
rising to 50 feet where it emerges from the base of the cone. The upper surface is deeply 
cleft and covered over with blocks of black cellular lava which rest upon one another in con¬ 
fused piles. Sometimes they are poised so insecurely on one another that it is a matter of 
some risk to attempt scrambling over them. Towards the base of the flow the rock from its 
slower cooling is more compact and less cellular. In places it contains white crystals of a 
mineral resembling lencite. In others it is a true basalt with numerous crystals of olivine. 
As pointed out by Dr. Leibig, the older lava seen in the section of the ridge differs from 
this ; it consists of a reddish matrix with crystals of felspar (probably sanidine), olivine, and 
augite. A somewhat similar rock occurs on Narkondam. 
On our way to the central cone from the landing place we at first endeavoured to avoid 
the rough surface of the lava-flow by keeping on the slope of the gap; but after a short 
distance tbe bushes and unevenness of the grouud compelled us to strike down on tbe lava, 
when we found, to our astonishment, a sort of path which must have been made by the 
committee sent from Port Blair to report upon the grass. 
Arrived at the foot of the cone, we commenced the ascent from the west. The loose 
ashes and shingle rendered it somewhat toilsome work ; and those in front found it difficult 
to avoid loosening fragments of lava which hounded down the hill in a most unpleasant way 
for those who were following. 
Dr. Liebig appears to have ascended from the north side, where it seems to have been 
equally difficult. 
About if of tbe way from the top there is a shoulder of rock which shows very well in 
the photograph. This probably marks the position of an old vent. There is a good dea. 
of firm ground about it. 
The summit of the cone is truncated, and contains an oval-shaped depression, one-half 
of which is 'partly filled with debris, and the other, some 20 yards in diameter and 50 feet 
* The Andaman Committee do not appear to have realised this fact, as they spent no little time and trouble 
in excavating a well without finding a trace of water. 
