﻿Acetylene. 109 



summary seems unfavourable to use of liquefied acetylene,, 

 except in places where sufficient space can be had to 

 isolate the cylinders as gasoline tanks are now isolated. 



It will be seen later that these cylinders may be ex- 

 posed to a special danger, although a very improbable 

 one, from the explosive decomposition of acetylene under 

 the impulse of a certain kind of shock. 



The Temperature of the Acetylene Flame. 



When we compare acetylene and common gas illumi- 

 nation from the point of view of the products of com- 

 bustion which vitiate the air of a room, or of the heat 

 which is given off', the conclusions are very favourable to 

 acetylene lighting, because ten times as much common 

 gas has to be burnt to obtain the same amount of light. 

 as would be given by a unit measure of acetylene. The 

 heating effect, however, is not in the ratio of ten to one. 

 Ten cu. ft. of Boston gas give 2.42 times as much heat as 

 1 cu. ft. of acetylene. 



Prof. Lewes^ has calculated the amount of carbonic 

 acid given off by different illuminants, and linds, for an 

 equal amount of light,, that coal gas gives off six times 

 as much as acetylene, and he estimates that the heat from 

 acetylene would not be much greater than from the ordi- 

 nary incandescent lamp. 



The true relations are for the same amount of light : — 

 Heat from incandescent light, 1 ; acetylene, 3 ; water 

 gas, 9. 



Prof. Lewes says, in the same connection : — " The flame 

 of acetylene, in spite of its illuminating value, is a dis- 

 tinctly cool flame, and in experiments which I have made 

 by means of the Lechatelier thermo-couple, the highest- 

 temperature in any part of the flame is a trace under 

 1,000° Cent. While coal gas, burning in the same way 



1 A p«per read before the Society of Arts, London, 



