EXPERIMENT ON CANDLE LIGHT. 219 



XIV, 



Experiment to determine the relative Quantities of Light afforded 

 by Candles of different Dimenfions, in a Letter from a Cor- 

 respondent. 



To Mr. NICHOLSON. 

 SIR, 



A HOUGH your ingenious correfpondent Mr. Ezekiel Prefatory re- 

 Walker, aflerts with confiderable decifion, that the light af- ?*«J£5 ,n 

 forded by candles, is proportioned to the quantity of material perimentsoa 

 con fumed, yet as he has not given the detail of his experi- light, &c » 

 ments, but feemsin fome meafure to have deduced thisrefult 

 by argument, from the fuppofed nature of the fubjecl ; and 

 as the quantity of light does undoubtedly follow a very dif- 

 ferent ratio in candles which require muffing, accordingly as 

 that operation is either performed or neglected. I think it 

 very detirable, that a courfe of experiments (hould be infti- 

 tuted for the purpofe of affording the refults you have your- 

 felf enumerated in your annotation upon one of that gentle- 

 man's papers. In the mean time, I prefent you with a tingle 

 experiment upon his two wax candles, which were taken by 

 me in preference, becaufe they require no fnuffing. 



One of thefe candles was a taper of iixteen to the pound, Experiment with 

 and meafured in length twelve inches; the other was a^j^^ 

 thicker candle of fix to the pound, and nine inches long. It candle. 

 is not neceflary to ftate the diameters, becaufe they are not 

 required in the prefent eftimate, and might if neceflary, be 

 deduced with greater precilion from the weight and length, 

 than from actual admeafurement ; and with regard to the 

 wicks, I have only to remark, that they were well adapted to 

 the candles — though it was impoffible for me to afcertain their 

 weight or finenefs in the manufactured ftate. 



Thefe two candles were lighted at the fame time, and when 

 tfiey were in the ftate of full and perfect combuftion, their 

 lengths were refpe&ively meafured and noted down. The 

 intenfities of their lights, were compared by the method of 

 fhadows. The diftance between the two candles was twenty- 

 four inches; and when the fhadows were of equal intenfity, 

 the diftance of thefcreen from the neareft candle was ieventy- 



two 



