1895.] in the Flames of Hydrocarbon Gases. 457 



separation of carbon. He also points out* that " combustible matter, 

 when diluted with indifferent gases, requires to be maintained at a 

 higher temperature, in order that it may burn with a luminous flame T 

 than when it is undiluted with such gases." 



Dr. Percy Erankland, in his researches on ths effect of diluents 

 upon the illuminating value of hydrocarbons,! showed that ethylene, 

 which was capable of developing a light of 68*5 candles power when 

 burnt by itself, became non-luminous when diluted with about: 



Hydrogen 90 per cent. 



Carbon monoxide 80 ,, 



Carbon dioxide , . . 60 ,, 



Nitrogen 87 



results which all show that excessive dilution by inert gases destroys 

 luminosity. 



In order to see if dilution had the same effect upon acetylene,, 

 experiments were made by diluting it with pure hydrogen. The 

 gases were mixed over water, the proportion of acetylene actually 

 present in the gas being determined by analysis at the burner, and 

 although the water in both holder and meter was, as far as possible r 

 saturated with the gas, yet, as the analyses show, the precaution was 

 an important one. 



Composition of mixture. 



Showing that dilution with between 80 and 90 per cent, of hydrogen 

 rendered the acetylene non-luminous when the mixture was burnt 

 from a burner suitable for the higher values of gas. 



In order to determine the point at which luminosity was destroyed 

 when consuming the mixture in a burner suited to develop the light 

 from a gas of low illuminating power, the experiment was repeated,, 

 using a 3-in. flame burning from the London argand, and also from a 

 No. 4 Bray union jet, the latter being employed as it is difficult to 

 determine the temperature in the argand flame. 



* ' Liebig's Annalen,' vol. 183, Part I, pp. 102131. 

 f ' Chem. Soc. Jour.,' vol. 45, p. 30 and p. 227. 



