PART 2.] 
Mallei: Mud volcanoes of Rdmri and Cheduha. 
208 
quantities of stones, and of mud, doubtless reduced to spray by the violence 
of the action, are being shot into the air, the friction of the ejecta amongst 
themselves, must necessarily produce large quantities of electricity, and it is, 
I believe, to the sparks, or lightning on a small scale, thus produced, that the 
ignition of the gas is due. The flames at the surface are sufficient to account 
for the calcination of the fragments of shale mentioned above. 
It will be observed that the fire of the mud volcanoes differs from that so 
often popularly spoken of in connection with lava-emitting volcanoes, in that 
the former is due to real flames, the latter being the reflection of the light from 
glowing lava by masses of condensed vapor, or of dust and scorire, or, in other 
cases, the light from Jets of incandescent lava-drops. 
In the mound south of Kyauk-gale we have an instance of a mud volcano in 
Extinct mnd volcanoes. dormant 
condition. Instead of the u.sual heap of bare stony- 
looking debris, the mound is clayey at the surface and covered thinly with grass, 
■with a few scattered ca-suarinas around. When I saw it there "oms one small mud 
cone at the centre from which bubbles of gas were being given off, but the amount 
of mud recently ejected,— i. e., covering, instead of covered by, grass,—did not 
exceed a few cubic feet. The mound, about 100 yards in diameter and perhaps 
15 feet high, is situated on a raised beach, whose present elevation of about 20 
feet above the sea only dates back to the middle of the I6th or 17th century 
Previous to that time there may of course have been submarine eruptions, but if 
so, the loose ejecta must have been canned away by the sea. The present mound 
can never have been exposed to the surf, and as it is now very nearly extinct, 
the maximum length of its pjeriod of subabrial activity can be inferred. 
The third of the Kyauk Phyu volcanoes, counting from the sea, is in a still 
more advanced stage. It is a cone of low gradient, ■with a depression a few yards 
m diameter at the summit, containing a pool of water bordered by I’ushes— 
a miniature crater lake. The cone is thinly overgrown with gi-ass, and casuarinas 
are dotted over it accompanied by other trees. After eruptions have ceased, the 
salt is gradually washed out of the debris by rain; slowly probably on account 
of the impervious character of the mud. The cone thus by degree.s becomes 
less fit for the gro^wth of casuarinas, and more suited to that of ordinary Jungle, 
which ultimately doubtless usurps the place of the former trees completely. 
I have already alluded to the position of the Arrakan salses at or near the 
^.. . „ , , end of the great Sunda group of volcanic vents. 
Ungin 01 the mud volcanoes. .vt i t 1 i t-i 
The next to them are iNarkondam and nari-en Island, 
both of which are volcanoes in the ordinary sen.se of the term. 
There is of course a wide gulf between the two classes of volcanic phenomena. 
Indeed some authorities, like Dr. Daubeny and Mr. Scrope, do not regard salses 
as truly volcanic at all, grouping them as pseudo-volcanic phenomena. 
For the production of any volcanic cone tlu’ee main conditions are necessary ; 
1st, the reduction of rock at a greater or less depth beneath the surface to a 
mobile condition; 2nd, a practicable vent by which such rock can be forced to 
p. 190. 
