214 Of the Light tnanifested in Combustion. 



The object I had particularly in view was to de- 

 termine whether the quantity of light disengaged 

 in the combustion of inflammable bodies is or is not 

 in a constant invariable proportion to the quantity of 

 inflammable matter which is burned ; and as the flame 

 of an Argand lamp, well arranged, is exceedingly 

 bright, and when purified oil is used gives neither 

 smoke nor smell, I endeavoured to find out whether 

 the quantities of light which that beautiful lamp dif- 

 fuses are always as the quantities of oil which are 

 consumed. 



First Experiment. — An excellent Argand lamp, 

 which had been most carefully cleaned and trimmed, 

 was weighed and lighted and immediately placed 

 before the photometer, where during 30 minutes it 

 was so regulated as to furnish constantly just 100° of 

 light (the same quantity that the standard wax candle 

 furnished). 



At the end of this experiment the lamp was extin- 

 guished ; and on weighing it carefully it was found 

 that 8 grammes of oil had been consumed, = 114 

 parts. This gives 228 parts of oil per hour for 100° of 

 light, or for 100 parts of oil 48° of light, furnished 

 uniformly during one hour. 



The standard light consumed 100 parts of wax per 

 hour, and furnished uniformly 100° of light. 



Second Experiment. — The lamp having been most 

 carefully cleaned and trimmed was again weighed and 

 placed before the photometer, opposite to the division 

 of its scale marked 200°, when having been lighted 

 it was so managed during 30 minutes as to furnish 

 constantly just 200° of light, equal to that of two 

 wax candles. 



