On the tajl of llluminailott by different Kinds of Candles. 185; 



burning for one hour, it loft 250 grains of weight, fo that the whole time of its combuftion 

 would have amounted to 4 hours, 12 minutes. Whence it follows, that the candles made 

 of fpermaceti are far lefs oeconomical with regard to expence, than wax or tallow. Bcfides 

 which, the flame produced by this candle was very unfteady, fleeting, and it alfo gave out 

 ?. quantity of fmoke and foot. 



Eighth experiment •with a candle compofed of equal parts of fpermaceti and talloiu. — This 

 candle weighed 2 ounces, 6 drachms, and 4 grains, (4|- Loth.) I fufFered it to burn one 

 hour, and found it to have loft 2x3 grains j whence the whole time of its combuftion 

 would have been 5 hours 22 minutes. Its flame difl^ered very little from that obferved ia 

 the foregoing experiment. 



Ninth experiment with a candle made of one part fpermaceti and two parts of tallow. — The 

 weight of a candle of this mixture was 2 ounces, 6 drachms, and 5 grains, (4I Loth.) of 

 which it loft 200 grains by one hour's burning. Its total combuftion, therefore, would 

 have been accompliftied in 5 hours, and 43^^ minutes. This candle guttered or overflowed 

 very much, and afforded a bad, footy flame. 



Tenth experiment with a candle prepared of one part of fpermaceti mixed with three parts of 

 tallow. — This candle weighed exaftly 2 ounces, 6 drachms, and 45 grains, (4I Loth.) By 

 burning for one hour, it fuftained a lofs of weight of 235 grains ; hence the whole time of 

 its combuftion would have amounted to 5 hours and 3 minutes. The flame of this candle 

 alfo was not notably different from that of the laft. 



Eleventh experiment with a candle compofed of equal parts of wax and fpermaceti, together 

 with three parts of tallow. — The weight of this candle amounted to i ounce, 6 drachms, 

 and 56 grains, (3^ Loth.) During the combuftion for one hour it loft 246 grains, and 

 would confequently have lafted 3 hours, 54 minutes, before it was intirely confumed. In 

 other refpefls the flame of this candle was very bad } and it depofited a quantity of fmpke 

 and foot. 



Computation ^ the Expence attending the Confumpfion of thefe different Kinds of Candles com- 

 pared with each other. 



In order to obtain a very accurate proportion of the faving of expence that might be 

 made by burning thefe various fpecies of candles, it would be neceflary, not only that the 

 candles themfelves (hould confift of equal maflTes, but likewife of equal diameters or cir- 

 cumferences : for fince, as I fliall prove in the fcquel, it refults from my experiments, 

 that the faving in the burning of a candle is proportional to the fmallnefs of its diameter, 

 and fince the candles employed in experiment 3 and 4 had a fmaller diameter than the 

 others, the following calculation with regard to the oeconomy in burning thefe two fpecies, 

 is only an approximation j whereas it is perfeftly accurate with regard to all the others,. 

 becaufe they were ufed of exaftly the fame diameter. It will be eafily perceived, that I 

 have calculated the faving to be made ia the burning of » candle from the (juamity of fuet 

 3 or 



