t88 On the Cofl of Illumination l>y different Kinds ofCandlet, 



Firjl experiment with a wax candle of the fixe of fix to a pound. — A white wax candle 

 weighing exaftly 2 ounces 11 drachms {^\ Loth.) avoirdupois iveight*, was lighted and 

 kept burning for one hour in a calm place ; after which combuftion it exhibited a Icfs of 

 weight of 115 grains. According to this proportion the combuftion of the whole candle 

 would have required 1 1.2 17 hours, or which is the fame, 11 hours and 13 minutes. The 

 burning of this candle proceeded quietly, with a tranquil, not undulating flame, and with- 

 out notable fmoke and foot. 



Second experiment -with a mould tallow candle of fx to the pound. — The candle weighed 

 a ounces, 10 drachms, {^\Loth.) and loft in weight 185 grains after an hour's burningi 

 the whole of it would therefore have been intirely confumed in 6 hours and 45 minutes* 

 The flame was flightly agitated, and emitted much vapour. 



Third experiment with a mould tallow candle of eight to the pound.— The weight of this 

 candle was i ounce, 15 drachms, and 4 grains (3!- Loth.) When it had burned one hour, 

 it had loft 1 40 grains ; whence it might have burned 6 hours and 40 minutes. The other 

 phenomena during its combuftion were like thofe of the preceding. 



Fourth experiment with a mould candle of nine to a pound. — Its weight was I ounce 12 

 drachms, (3^ Loth.) and the lofs of Weight after one hour's burning was 140 grains ; con- 

 fequently this candle would have lafted feven hours before its intire confumption. The 

 flame refembled that of the laft. 



The refults afforded by thefe experiments appear to me deferving of attention in various 

 points of view. It was on this account that I refolved to make various kinds of candles, 

 compofed of pure fpeimaceti, of fpermaceti and tallow, and of tallow and wax, in various 

 proportions of tlie ingredients. And laftly, I made trial of a mixture of wax, tallow, and 

 fpermaceti. The refults which I obtained in thefe experiments were the following : 



Fifth experiment with a mould candle, made of two parts of tallow and one of wax. — This 

 candle weighed Z^ ounces, 24 grains (5 Loth.) It was lighted, and after an hour's com- 

 buftion loft 166 grains ; it might confequently have burned for the fpace of 7 hours and 

 22 minutes. The flame of this candle was a very good one ; It emitted fcarcely any va» 

 pour, and in this refpeiSl it very much refembled the candle made of pure was:. 



Sixth experiment with a candle manufaElured of one part wax and three parts of tallow.-^ 

 The weight of this candle was 2 ounces and a half, and 34 grains. From the lofs of 19,3 

 grains, which it fuftaincd by burning one hour, it appears that it would have required 

 6 hours and 23 minutes to be wholly confumed. The flame of this candle was likewife 

 fteady, and afforded but a fmall quantity of foot. 



Seventh experiment with a mould candle made of pure fpermaceti. — ^I made a candle of this 

 defcription, of the weight of 2 ounces and 3 drachms, (4^ Loth.) When lighted and kept 



• The Berttn pound of 32 Lcths, or 16 ounces, is equal to 3616.3 Englifh grainsi fo that one ounce 

 Berlin is equal to 226, and the drachm to 14. | Englifli grains, diiiegarding the fmall decimal fraflion of 

 3-lOths of a grain in the pound. The fubdivillon of the Englirti avoirdupois weight into 16 ounces, each. 

 into 16 drachms has been employed here without faither reduftion.—Tranfl, 



burning 



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