1895.] Extinctive Atmospheres produced by Flames. 



355 



Percentage Composition of the Residual Atmosphere and of the 

 Artificial Atmosphere in which Flame is just extinguished. 



In the above table the results are given, which were obtained by the 

 analysis of the residual atmospheres, in which the flame had burnt until 

 it was extinguished. Since the proportions of carbon dioxide contained 

 in these atmospheres are small, the composition of the artificial atmo- 

 spheres consisting of nitrogen and oxygen only, in which the flames 

 were just extinguished when they are inserted, are also stated for 

 comparison. It will be noticed that the general agreement in com- 

 position shown by the two classes of extinctive atmospheres, so 

 differently produced, is well maintained ; and when the conditions of 

 the experiments are taken into account the recent series of results are 

 confirmatory of the general accuracy of those previously obtained. 



I have to acknowledge the assistance rendered by M. E. Feilmann, 

 B.Sc., in carrying out the experimental work involved in this 

 investigation. 



[February 18, 1895.] It is noteworthy that the composition of the 

 extinctive atmosphere produced by the flame of a candle, or of oil, or 

 of alcohol, closely corresponds with the average composition of air 

 expired from the lungs. The composition of the last portion of air 

 which is expired varies somewhat with the length of time during 

 which the air has been retained in the lungs. The following percentage 

 composition by volume was determined : 



