9 I Prof. V. B. Lewes. [Feb. 1, 



containing sodic pyrogallate and sodic hydrate, to absorb all traces 

 of oxygen, and on analysis gave 



Ethylene 98'80 



Nitrogen 1'20 



The gas was then passed through the combustion tube, until it was 

 considered that all air had been displaced, and the tube was main- 

 tained for 100 hours at 400 C. Oil and a very small quantity of 

 carbon deposited in the tube, and the volume decreased from 100 

 to 61. The gas was then removed from the tube and analysed. 



In all the analyses described in this paper the following procedure 

 was adopted. Carbon dioxide was absorbed by means of a 50 per 

 cent, solution of sodic hydrate, the oxygen estimated by absorption 

 with alkaline pyrogallate, the unsaturated hydrocarbons next ab- 

 sorbed by means of a solution of bromine in potassium bromide, care 

 being taken to remove bromine vapour from the gas by agitation with 

 caustic soda before measurement, the carbon monoxide was next 

 estimated by acid cuprous chloride, and after removal of any acid 

 fumes the residual gas was treated with paraffin oil, previously 

 prepared for use by heating it over a water-bath for at least an 

 hour. 



Experiments show that in the case of mixtures of methane with 

 higher members of the same group, agitation with paraffin prepared 

 in this way, or mere standing in contact with it with occasional agita- 

 tion for twenty to thirty minutes, will remove the ethane and any 

 higher saturated hydrocarbons which may be present, together with 

 a small proportion of the methane. The amount of residual methane 

 can then be determined by explosion with oxygen, and subsequent 

 estimation of the carbon dioxide formed, the volume of gas absorbed 

 by the paraffin plus the volume resulting from explosion giving the 

 total volume of saturated hydrocarbons. Details of the results ob- 

 tained by this method of procedure when dealing with gaseous 

 mixtures of known composition will be found, ' Jour. Soc. Chem. 

 Industry,' vol. 10, p. 407. 



The analysis of the heated ethylene gave 



Carbon dioxide 0'82 



Oxygen O'OO 



Unsaturated hydrocarbons 7'00 



Carbon monoxide 1'17 



Saturated hydrocarbons Paraffin. . 40' 18 "I , .<,<> 



Explosion 21-64 / 



Hydrogen 22'18 



Nitrogen 7'01 



100-00 



