98 ON THE ABSOEPTION AND EADIATION OF HEAT BY GASEOUS IkiATTEE. 
purchased, burnt for an hour at Chamouni, and the loss of weight determined. The 
same candles were lighted for the same time on the summit of the mountain, and the 
consumption determined. Within the limits of error, the consumption above was equal 
to that below. The light below was immensely greater than that above, still the amount 
of stearine consumed in the two cases was sensibly the same. Professor Feaxelaad 
sm'mised this to be due to the greater mobility of the rarefied air, which allowed a freer 
interpenetration of the flame by the oxygen *, and the foregoing experiments show that 
the augmentation of mobility is just such as would account for the observed effect. 
* The influence of interpenetration is ■well seen in the exposed gas-jets of London, particularly iu the 
butchers’ shops on a Saturday night. A gust of wind, which carries oxygen to the centre of a flame, sud- 
denly deprives it of light. A simple and beautiful experiment consists of passiug a lighted candle swiftly 
to and fro through the air ; the white light reduces itself to a pale-blue band. Buxsex’s burner is an illus- 
tration in the same fine. 
