a Proceedings of Philosophical Societies. [Fre 
not exceed. With the exception of one spot, the shores are 
generally shelving. The mountains and plains are generally 
covered with accumulated debris, and the soil, which is poor, 
corresponds to the rocks from which it is derived; the water is 
pure, and of the mean annual temperature of the place where 
it rises, except in the neighbourhood of Trincomalee, where 
there are hot springs of 103° to 137°. 
The valleys are in general narrow and deep, with outlets which 
render them incapable of forming lakes ; but there are some 
salt lakes formed by the sand banks thrown upon the sea- 
shore. ; 
Besides the two species of rock before spoken of there are 
masses of granite, both common and graphic, sienite, felspar, 
rock, and greenstone. 
Tron in different forms is general in the island, but no other 
metal has been discovered : its poverty, however, in this respect 
is not less remarkable than its richness in rare and valuable 
gems, which are scattered through the alluvial ground, but are 
seldom found in their native rock. The mimerals which have 
been observed by Dr. Davy are quartz, cat’s-eye, prase, hy- 
alite, &c. Tourmaline, garnet, pyrope, cinnamon-stone, zircon, 
hyacinth, spinelle, sapphire, and common corundum, several 
varieties of felspar, mica, carbonate and anhydrous sulphate of 
lime, apatite, graphite, and ceylonite. No traces are visible of 
volcanic action in any part of the island. 
A communication was read from Ed. L. Irton, Esq. of Irton 
Hall, on a third sand-tube found at Drigg. 
The remains of this tube were discovered about 10 or 15 
yards nearer to the sea than the former ones. Passing through 
about four feet of pebbles, its course was continued nearly 
eight feet through wet sand; it then became much contorted 
and irregularly formed, sometimes being. solid, and again be- 
coming tubular, and terminating at a granite pebble with only 
a small diverging ramification extending but a few inches. 
SOCIETY FOR THE ENCOURAGEMENT OF ARTS, MANUFAC- 
TURES, AND COMMERCE, 
We hope in future to present our readers with notices of the 
more important communications made to this Society, and to 
which the Society has voted rewards. Since the commencement 
of the present session, in November last, rewards have been 
adjudged for the following interesting subjects. 
Mr. W. Hardy’s Inverted Pendulum.—tThis valuable instru- 
ment has already been made known to the Sea by Capt. 
Henry Kater, F.R.S. in a late paper in the Transactions of 
the Royal Society, contaming “ An Account of Experiments 
for determining the Length of the Pendulum, vibrating Seconds, 
in the Latitude of London ;” who derived considerable adj 
vantage from it, in proving the stability of the support for his 
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