Of the Light manifested in Combustion. 2 1 5 



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 1 00 parts of oil 1 1 2° 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 



