( 6 ) 
# 
Macpherson’s Straits, owing to its more abrupt coasts, does not exhibit 
this phenomenon, as far as I was enabled to ascertain. 
It is also a matter of great interest to decide the question whether the 
rapidity of the submersion takes place equally through the whole group of 
islands, or rather whether it is a decreasing one towards the northern 
extremities. 
Dr. Mouat, in Ms able account of the Andaman Islands (Selections from 
the Government of India, No. XXV.), maintains quite a contrary view of this 
subject, as is shown in his preface, where, writing about the Andaman Islands, 
he says—“ They are collections of islands surrounded by most dangerous coral 
reefs, which are gradually forming innumerable islands, as each becomes lifted 
above the surface/ 5 &c. 
Dr. Von Liebig (in the same Records, p. 127) points to a probable rising 
of Barren Island, recording thus—“ One of the most remarkable amongst 
these was a stratum of rounded stones, like large pebbles, cemented by tufa, 
exactly like those of the present beach, but at a considerable elevation (about 
20 feet) above the high water-mark, showing that the sub-marine base of the 
island must have been raised since those pebbles had been washed by the sea.’ 5 
Dr. Playfair (c., p. 123), however, says— “ I could not, after very careful 
examination, satisfy myself that there had been any recent upheaval of the 
islands, none of the rocks exhibiting signs of having been water-worn.” 
It may be remarked that Barren Island is an active volcano, and, therefore, 
rising and sinking can take place here as a local phenomenon. 
Prom a practical point of view, the fact of a sinking state is of impor¬ 
tance, as we see all along the shores small fertile valleys opening towards the 
sea, and preparing themselves gradually for mangrove swamps. 
Suppose the gradual submersion to he one foot in a hundred years (which 
is rather a low estimate), we should see in a thousand years all the stores and 
houses along the beach at Ross Island submerged, while Middle Straits and 
so many harbours now dangerous would become open for navigation. 
10. The temperature during April was very regular, ranging from. 
„ , .... . 86° to 87° at 6 a. m., to 91° at 1 p. m., in rare 
instances rising as high as 92 . During the night 
the thermometer sank to 85 and 86°. The atmosphere appeared tolerably dry. 
As, however, I had no instruments at my disposal, I could not make any 
observations of the amount of moisture it contained. 
About the 10th of May the regular rains set in with great force, and after 
that date there was scarcely any day without some heavy showers. The 
atmosphere became more and more saturated with moisture, the nights became 
cool, and the thermometer stood sometimes as low as 78° towards the morning, 
rising at midday to 80 and 81°. The temperature was commonly 82 to 84° at 
1 p. m., but it rose quickly to 90 and 91° whenever a few hours of sunshine 
prevailed. 
In June, the rains became heavier, and thunderstorms were frequent at all 
hours of the day. The saturation of the atmosphere was then great. The 
temperature at about 6 a. m. generally was as low as 74°, but often only 73° or 
even 72°, rising to 82° and 83° at 1 p. m., and sinking to 78° and 79° during the 
night. In the latter half of this month, the heat increased, the thermometer 
indicating a mean height of 80*7° in the mornings, 83*7° at midday, and 81*1° 
in the evening. The showers during May and June were rarely of long 
duration, hut came abruptly with great force at short intervals. I counted 
during 12 hours of daylight on the 18th June not less than seven heavy showers. 
In the first half of July, the heavy rains ceased, and several fine but 
cloudy days occurred alternately with rainy ones. The temperature decreased 
