122 Experiments of Candle Wicks, Sfc 



from the combustible compounds lowers their temperature. 

 . renders the combustion less complete, and produces a yellow 

 flame instead of the usual white flame which diffuses more 

 light. In consequence of this imperfect combustion, a portion 

 of carbon is deposited, which either passes off in the form of 

 smoke, or adheres to the Wick increasing- its size. It is there- 

 fore of importance that the "Wick should be of a proper 

 length, that it may on the one hand afford sufficient surface? 

 on which combustion may take place, and on the other not 

 diminish more than is necessary the effect of the light which 

 the combustion renders sensible. 



The thickness of the Wick is of importance as well as its 

 length. When not sufficiently thick it is apt to incline down- 

 -ds and fall upon the Candle; or if it remain upright it 

 s not attract a sufficient supply of melted Tallow for the 

 combustion: when it is too thick, though a sufficient quantity 

 of melted Tallow may be attracted and consumed, the illumi- 

 nating effect is diminished in the same way as when it is too 

 long, the diminution being greater in proportion to its size. 

 To remedy this it was suggested to me to try the effect of a 

 flat Wick ; accordingly I made a Candle with a Wick con- 

 sisting of three separate Cords placed in a plane with each 

 other, the breadth of which consequently exceeded its thick- 

 ness; I also made another Candle with two Wicks placed at a 

 distance from each other, each Wick containing live threads; 

 a third with three Wicks each, containing five threads ; and a 

 fourth with one round Wick, containing twenty threads, and 

 compared the illuminating effect of each with that of a common 

 Wax Candle. The manner in which the experiment was made 

 was the following : two square boxes were procured, each 

 having one side open, the top and bottom being closed, these 

 were placed with the open sides facing a wall ; in one I 

 placed t'ne Wax Candle, in the other box each of the other 

 Candles successively, and between the two boxes a cylindrical 

 object at trie distance of four inches from the wall. Both 

 Candles being lighted and snuffed so as to have the Wicks of 

 the length best adapted for giving the maximum of light. 

 Keeping the Wax Candle at the distance of 18 inches from 

 the wall, the others were moved backwards or forwards accord- 

 to circumstances, so as to obtain a shadow of equal 

 intensity from each Candle. The following are the results 

 which I obtained, but which considering that the flame of a 

 Candle is at all times variable, can only be looked upon as 

 approximations to the average effect. As the number 18 

 indicates the distance in inches at which the Wax Candle was 

 placed from the wall, so the number opposite eacli of the other 

 Candles shows the distance at which they severally produced 

 .a light equal to that from the Wax Candle. 



