Of the Light manifested in Combustion. 215 



In this experiment 10.3 grammes of oil were 

 consumed. This is at the rate of 271 parts of oil 

 per hour for 200 of light, or for 100 parts of oil 74 

 of light 



Third Experiment. The lamp having been cleaned 

 and properly arranged was again placed before the 

 photometer. In this experiment it was made to fur- 

 nish 300 of light during 30 minutes, and 10.7 grammes 

 of oil were consumed. This is at the rate of 305 parts 

 of oil per hour for 300 of light, or for 100 parts of oil 

 98 of light. 



Fourth Experiment. In this experiment the lamp, 

 which had been arranged with the utmost care, fur- 

 nished during 30 minutes 400 of light, and consumed 

 12.7 grammes of oil. This is at the rate of 361 parts 

 of oil for 400 of light, or for 100 parts of oil 112 of 

 light. ^ 



This is the first experiment in which a given quan- 

 tity of oil was found to furnish more light than an 

 equal quantity of wax. But without stopping here to 

 make any particular remarks on that circumstance I 

 shall hasten to give an account of still more interesting 

 results. 



In order to shorten my narrative as much as pos- 

 sible, I shall here place in a table the results of the 

 four experiments of which I have just given the details, 

 and shall add to them the results of five other simi- 

 lar experiments which complete this particular course. 

 These nine experiments were all made on the same 

 day, with the same lamp and the same standard light ; 

 and I will venture to say that no pains were spared to 

 render them as complete and satisfactory as possible. 

 Their results are so very striking that they hardly stand 



