conformity with the Dynamical Theory of Heat and Gases. 257 



A hydrocarbon, C 2 H 5 = 29, lias been discovered in addition 

 to etherine, C 2 H 4 =28, and defiant gas, CH 2 = 14. Ether, 

 C 2 H 5 0* = 37, is considered better represented by C 2 Ii 5 . 0* 

 than by C 2 H 4 . HO*; alcohol better represented by C 2 H 5 . 0*. HO*, 

 with some mark or expression appended to signify that such a 

 molecule occupies two volumes, than by CH . HO* = 23 without 

 any mark. 



As the chemical evidence with respect to the formation of ether 

 and decomposition of alcohol is not deemed of importance, I may 

 revert to a fact which appears from the researches of MM. Fabre 

 and Silberman, namely that the quantity of heat evolved by the 

 combustion of alcohol and ether is exactly equal to what it would 

 be if they were simple hydrates of CH 2 and C 2 H 4 . These (and 

 all other ?) hydrocarburets, when burnt, evolve the same amount 

 of heat as if the carbon and hydrogen were burnt separately; so 

 that the force of union between the C and H of these bodies 

 appears to have no sensible dynamical equivalent as between the 

 C and of carbonic acid, and H and of water, which unite 

 with an immense evolution of force. The heat developed in 

 burning a unit weight of ether, C 2 H 4 . HO* = 37, is 16249; in 

 burning the C 2 , or § ^ths of a unit weight of carbon separate, the 

 heat is 9430, and the H 4 , or 3 4 f ths of a unit weight of hydrogen 

 separate, is 6700 : these two added make 16130, being almost 

 exactly the same as the unit of ether. If the other element of 

 hydrogen belonged to a hydrocarbon and not to a water-molecule, 

 there would be 1675 to add. The same mode applied to alcohol 

 and pyroxylic spirit gives results even more striking, and pre- 

 cisely such as might be expected if they were hydrates of C 2 H*, 

 CH 2 , C* H respectively. 



What is the nature of the evidence afforded by the organo- 

 metallic bodies? "Ethyle is a colourless gas burning with a 

 brilliant white flame, and decomposes at less than a red heat," — 

 so far being similar to olefiant gas. Its specific gravity is 29, 

 the carbon being 24, and hydrogen 5. The sulphide and bisul- 

 phide of ethyle have vapour-densities such that they may be 

 regarded either as primary compounds of this gas and sulphur, 

 or secondary compounds of etherine and the sulphuretted hydro- 

 gens. The chloride of ethyle has vapour-density 32 1 ?, being 18 

 chlorine, 12 carbon, and 2 J hydrogen. It may thus be viewed 

 as half 'a gas-molecule of chlorine combined with half a gas- 

 molecule of ethyle, or one gas-molecule of olefiant gas in union 

 with one gas-molecule of muriatic acid. The same remark 

 applies to the iodide and bromide, also to the oxide (ether). 



The hydride of ethyle has specific gravity 15, the carbon 

 being 12 and hydrogen 3, being half a molecule of ethyle com- 



Phil. Mag. S.*4. Vol. 26. No. 175. Oct. 1863. S 



