140 Proceedings of Philosophical Societies. [Fes. 
the second and third lines, 940 feet; the elevation of the others 
was not ascertained. The mean elevation of the flats and valleys, 
and champaign land of the county, is about 240 feet. 
Most of the individual mountains, and the chains themselves, 
generally speaking, have a greater declivity to the S. than to the 
N.; but this declivity is more rapid on the N. than on the S., 
amounting in the former to eight, and in the latter to only two, 
feet in 100. The slopes to the N. are encumbered, and rendered 
uneven, by fallen blocks and bowlders, while those to the S. are 
quite smooth and even. 
A letter from the Rev. Archdeacon Barnes to Mr. Buckland, 
dated Bombay, March 31, 1815, was read. 
In this letter Mr. Barnes communicates, on the authority of Mr. 
Copland, Assistant Surgeon to the European forces in the Guzerat, 
some particulars relative to the carnelians of Cambay. 
These are all procured from the neighbourhood of Broach, by 
sinking pits during the dry season in the channels of torrents. The 
nodules which are thus found lie intermixed with other rolled 
pebbles, and weigh from a few ounces to two or three pounds. 
Their colour, when recent, is blackish olive, passing into grey. 
The preparation which they undergo is, first, exposure to the sun 
for several weeks, and then calcination. The latter process is per- 
formed by packing the stones in earthen pots, and covering them 
with a layer five or six inches thick of dried goat’s dung. Fire is 
then applied to the mass; and in 12 hours time the pots are suffi- 
ciently cool to be removed. The stones which they contain are 
now examined, and are found to be some of them red, others pink, 
and others nearly colourless; the difference in their respective tints 
depending in part en the original quantity of colouring matter, and 
in part perhaps on the difference in the heat to which they have 
been exposed. 
—=__—— 
ROYAL INSTITUTE OF FRANCE, 
Account of the Labours of the Class of Mathematical and Physical 
Sciences of the Royal Institute of France during the Year 1814, 
MarTHEMATICAL Part. 
By M. le Chevalier Delambre, Perpetual Secretary. 
(Continued from vol. vi, p. 463.) 
M. Mongez, Member of the Class of Ancient History and Lite- 
rature, has presented to that of the Sciences an antique piece of 
armour found on the banks of the Somme, and which is formed of 
a flint fixed in a handle of hart’s-horn. ; 
M. Barbie du Bocage, Member of the same Class, has’ read a 
memoir of M. le Comte Andreossi on the bosphorus of Thrace, in 
which there is a long diseussion about the actual state of the shore, 
which ought to furnish important information to judge of the 
