1820.] Mr. Dalton on Sulphuric Ether. 131 



no doubt the volume of gas would be greaily increased, and end 

 in pure hjalrog'en mixed with azote. 



These experiments are not decisive ; but they evidently point 

 out the composition of the atom of ether to be 1 carburettedf 

 hydrogen, 1 charcoal, and 1 water, or 2 defiant gas, and 1 water. 



The best method of analysis is by firing the vapour of ether 

 mixed with oxygen gas in Volta's eudiometer. This method I 

 discovered in September, 1803, and have used it occasionally 

 ever since. It may be proper to describe the various modifica- 

 tions of which this process is susceptible. 



When a few drops of ether are passed through water into tlie 

 eudiometer containing oxygen gas, the volume of the gas is in u 

 few minutes enlarged more or less, according to the temperature. 



In temperatures from 60° to 70°, the volume is about doubled; 

 but belovv' those it is less than doubled ; and above more than 

 doubled, agreeably to the principle before explained. 



(«) If the air be doubled or more, and an electric spark be 

 taken in it, the probability is, that no explosion will ensue ; if by 

 repeated sparking an explosion take place, it is feeble, and may 

 be repeated a few seconds aftervvards, sometimes once or twice. 

 The residue of gas being examined is found to contain a little 

 carbonic acid, some new combustible gas, and oxygen in varioiis 

 proportions. In short, the operation is very incomplete, owing 

 to an excess of ether vapour. 



(J)) If the oxygen gas be good, and the volume be increased 

 from 100 to 160 by the vapour (which will natural'v arise in 

 temperatures between 40° and 50°, and in higher temperatures 

 the volume may be reduced by cautious agitation, till the water 

 has absorbed part of the superfluous ether and vapour), then a 

 spark produces a violent explosion. The gaseous volume is 

 doubled, or from 150 becomes 300 ; and upon examination is 

 found to consist of carbonic acid and new combustible gas, but 

 chiefly the latter. Little or no oxygen is found. 



If the ether vapour be only from 3 to 10 per cent, of the 

 volume of oxygen, the explosion is vigorous, and a complete 

 combustion takes place. The residue consists of carbonic acid 

 and oxygen gases only. Ten volumes of ether vapour require 

 about 60 of oxygen, and produce about 40 of carbonic acid. 



(t) If 100 oxygen be increased by ether vapour to 120 or 130, 

 a violent explosion ensues, and the whole of the vapour is con- 

 verted into carbonic acid, water, and new combustible gas ; a 

 little charcoal is sometimes deposited, so as to make the air 

 umddy at the instant after explosion ; no oxygen is found in tlie 

 residue. 



{d) The combustion of ether vapour may be effected by com- 

 mon air as well as by oxygen gas, only the proportion of vapour 

 to air is very small and limited. If the vapour exceed five per 

 cent, it v/ill not fire ; and if it fall short of two per cent, it rarely 

 fires. The combuslion is attended with the production {;f ncvr 

 combustible gas, or otherwise complete, according to the 



I 2 



