218 Of the Light manifested in Combustion. 



made with a more simple apparatus, whose results 

 were extremely interesting. 



Fourteenth Experiment. As bleached beeswax is 

 one of the purest of -the inflammable substances used 

 in producing artificial light, I was desirous of finding 

 out whether the light furnished by wax candles of 

 different sizes is always in proportion to the quanti- 

 ties of wax consumed. To ascertain this point, I 

 began by placing a small wax taper, four tenths of an 

 inch in diameter, before the photometer, where it con- 

 tinued to burn very steadily during 30 minutes. 



As its wick was much thicker in proportion to its 

 diameter than that of a common wax candle, it fur- 

 nished very uniformly 64 of light, notwithstanding its 

 diminutive size. During this time it consumed at the 

 rate of 77 parts of wax per hour, consequently for 

 100 parts of wax it gave only at the rate of 83 of light, 

 instead of 100 which the standard light constantly fur- 

 nished. The result of the following experiment was 

 much more striking : 



Fifteenth Experiment. A small wax taper, with a 

 very thin wick (called a veilleuse in France), six tenths 

 of an inch in diameter and two inches in height, after 

 having been carefully weighed, was placed upright and 

 afloat in a small cylindrical vessel filled with water, 

 where it was suffered to burn quietly during two hours 

 and forty minutes : it was then extinguished, and, being 

 taken out of the water and wiped till it was quite dry, 

 it was again weighed, when it was found that just 

 4! grammes of wax had been consumed in the experi- 

 ment. This is at the rate of 25 parts of wax per hour; 

 and if this taper had given as much light, in propor- 

 tion to the wax it consumed, as a wax candle of the 



