M. Dumeril on the General Movements of Serpents. 235 
Table shewing Comparative Expense of Light from diferent Sources ; Coal-Gas 
containing 12 per cent. of matter condensible by Chlorine, taken as unity. 
Argand Gas, - P 1.00 
Fish Tail, 2 A lO es ish alls 51.00 
Single Jet, : : 1.80 ie 1.40 Jet, 1.00 
Solar Lamp, . : . 2.00 ay 1.55 nie 1.11 
Naphtha, 5 b 2.00 Soi 1.55 arp 1.11 
Solar Oilin common Argand, 3.98 one 2.84 aig 2.21 
Whale Oil do. 5.00 as 3.88 nee 2.77 
Sperm do. 8.00 ats 6.22 ae 4.4] 
Tallow Candle (2 wicks), 12.7 ae 10.0 m. 7.18 
Cocoa Candle, : : 13.1 ot 10.2 3 7.33 
Tallow do. (1 wick), 13.5 Age 10.5 * 7.50 
Composite, ‘ : . 145 ": 11.3 ia 8.12 
Palm, 5 5 : Ss 18.9 Ae 14.7 are 10.5 
Wax, : e : - 25.9 sop 20.1 snc 14,4 
Diaphane, F A , yea Se 21.1 ae 15.1 
Margerine, : : . 28.4 apts 22.6 m3 15.6 
Spermaceti, . : - 29.2 ae 22.7 Acc 16.2 
Composition, . 292 aad 22.7 ts 16.2 
On the General Movements of Serpents. By M. Dumerin. 
The manner in which serpents move is evidently the consequence of 
their absolute want of limbs; at the same time, their destination to live 
in atmospheric air is indicated by the presence of lungs. Serpents are 
besides under the necessity of providing for their subsistence solely from 
animal food, which they must seize in a living state, and swallow at once 
entire, since nature has not granted them, as with other reptiles, cutting 
instruments suited for dividing their food into regular portions. These 
circumstances united, have impressed the characters we find inscribed, 
not only on the exterior of the bodies of ophidians, in regard to their con- 
figuration, but also on the interior throughout the whole of their struc- 
ture. In the present case we are about to consider them merely in rela- 
tion to the movements which these animals execute. Even with this in 
view, we shall have occasion to describe some of the manners and habits 
of serpents, as well as the modifications which they have required in 
many parts of their organisation. 
The body of a serpent consists of a trunk considerably elongated, with- 
out any notable distinction of regions for the different parts of its extent. 
In the interior this body has for a solid stalk, or principal support, a very 
numerous series of small bones, which are moveable, although securely 
and strongly attached to each other. These are vertebrae, all of them 
