n 
[VOL, Tt. 
Records of the Geological Survey of India. 
up.^ The natives only drank cocoanut-water, and they probably obtain the fresh water 
which they require for domestic purposes, &c., like the boiling of Melon, from the fresh 
water swamps, which are locally to be met with in ravines. Of wells, except that made 
near the village Malacca on 1ST an cowry and which is now half in ruin, I saw nothing. 
Car-Nicobar, however, though also composed of argillaceous strata, as the abovementioned 
islands, has no want of good, drinking water, because the large coral land raised from 
8 to 12 leet above the level of the sea, permits the digging of those remarkable wells, the 
fresh water of which falls and rises with the ebb and tide. The explanation of this rare 
phenomenon does not rest in the filtering of the seawater by the coral-sand, but is 
rather the fact that the lighter rainwater floats on the heavier seawater, and the porous 
coral rock only prevents the mixing of the two. I have seen several such reservoirs on 
Car-Nicobar near the villages Mns and Saui, they were all dug from 8 to 10 feet 
through the coral mass nearly to the level of the sea at its highest flood, and contained 
good drinking water. Besides this, a river flows into the Northern Bay of Car-Nicobar, 
which we named Areca Bi ver from the luxuriously growing Areca-palms on its banks ; 
this river is navigable with flat boats two miles upwards, and near the small rapids which 
one meets it also offers good drinking water, containing only a small portion of calcareous 
constituents in solution. 
I have not become acquainted with any mineral or warm springs. The clay-marl 
rocks of the Nancowry haven are, however, seen covered with an inch-thick incrustation of 
sulphate of magnesia (epsom salts) in fine fibres with a silky lustre; this indicates a quantity 
of sulphate of magnesia in the clay-marls, and by digging holes in them, epsom salt waters 
may probably be obtained, such as is the case with the bitter sand 3 T -marls near Bilin in 
Bohemia. 
V.—Observations on the temperature. 
As we had, according to our instructions, to measure the temperature of rivers and 
springs, and as this task fell to my lot, as far as opportunity offered itself, I would put upon 
record here the few observations in this respect, besides a few remarks on the temperature. 
a.—Temperature of the different waters. 
1 . 
2 . 
3. 
4. 
5 . 
23rd February, on Car-Nicobar, water in the well near the village Saui in 8 feet 
depth in perfect shade 
27th February, on Car-N icoba r, Areea river in the shade of the primeval forest ... 
4th March, on Tillaug chong, western side, a spm>g ij, the shade of primeval forest 
4th March, on Tillan g chong, another spring 
8th March, on Nan cowry, old well of the Moravian Brothers near the village 
Malacc a, water in 8 feet depth in shadow 
25- 7C. 
25'0C. 
2.V5C. 
26- OC. 
25-7, C. 
If it were permitted to make from these few observations a conclusion upon the mean of 
the annual temperature of the Nicobars, this mean would be 25‘58C. (=78'04 Fahrt.) 
I have also measured the temperature of several other wells and streams, but as their 
water was temporarily exposed to the sun, very different results were obtained, as for instance: 
on € a r-N i c o b a r 
24th February, well near M u s, water in 3 feet depth 
25th „ a stream between M u s and Saui 
26th „ rivernearSaui 
onCamorta 
9th March, two streams with muddy stagnant water 
on P u 1 o M i 1 u 
18th March, stagnant, stream water 
27*0C. 
27-8C. 
29'OC. 
27 OC. 
26'5C. 
o.—Temperatures of the soil. 
To obtain further materials for the determination of the mean annual temperature 
I made a few observations on the temperature of the soil, and these gave the following 
results:— 
8th March, on Nancowry near the village In nan g, the thermometer, after it had been 
exposed in a permanently shaded place for 6 hours, showed, when buried in 3£ feet 
depth underground ... ... ... ... ... ... 25*7,C. 
20th March, on Kondul, also in 3£ feet after 6 hours ... ... ... ... 253,C. 
These two observations give, as did those made in water, an 
annual mean of 25'5,C. (=77'9 Fahrt.) 
