208 ANNUAL OF SCIENTIFIC DISCOVERY. 



this principle, the wicks may be modified to suit the various require- 

 ments of the different materials employed in candle-making, each of 

 which requires a different character of wick. This was shown by several 

 candles being burned, having wicks slightly differing from those which 

 were best for each particular case, proving that great observation and 

 skill are requisite in the manufacturer, in order to adjust the material 

 and wick to each other in every case. Attention was also called to the 

 fact, that, up to the present time, manufacturers have not been able to 

 employ platted wicks in wax candles or tallow candles. 



Ordinarily, in making mould candles, the wicks are placed by hand 

 into the moulds, and the same are retained fast therein by pegs at one 

 end and by wires at the other. A great improvement has been intro- 

 duced into this part of the mechanical processes, by causing the can- 

 dles, as they are discharged from the moulds, to draw fresh wicks into 

 the moulds ; and, on the candles being then cut off from the wicks, an 

 instrument takes hold, simultaneously, of all the wicks, and retains them 

 correctly in position in the several moulds. 



About thirty years ago, a celebrated French chemist, (Chevreul,) 

 when investigating the properties of fatty matters, discovered that they 

 consisted of certain acids ; and many efforts were made to introduce one 

 of the acids (stearic acid) into the manufacture of candles, but with 

 little if any practical effect, owing to its high crystallizing properties. 

 In order to correct this properly, recourse was had to the use of arse- 

 nic, which was found to break up the crystals ; and candles were 

 extensively made and consumed, rivalling spermaceti in appearance, 

 whilst they were sold at a much less price. But public attention hav- 

 ing been called to the injurious effects produced by the vapors of arsenic 

 thrown off by such candles, this greatly increasing manufacture met 

 with a severe check ; and, if the manufacturer had not discovered a 

 means of employing stearic acid without arsenic in the manufacture 

 of candles, the public would probably have ceased to purchase them. 

 This, probably, is one of the most interesting events in the history of 

 the manufacture. On investigation, it was discovered that the crys- 

 talline character found to prevail in stearic acid candles is consequent 

 on the pouring very hot melted stearic acid into cold moulds ; and it 

 was found that by pouring the matter when nearly set into moulds 

 warmed to about the same temperature as the candle stuff, and by 

 using a small quantity of wax, candles of stearic acid can be made pos- 

 sessing very excellent properties. Hence, this class of candles has of 

 late years very largely prevailed, which, being made with suitable 

 platted wicks, like spermaceti candles, do not require to be snuffed. 



Another class of candles, which came largely into use about the same 

 time, was produced from the stearine of cocoa-nut oil ; but this candle 

 required snuffing. A great step of improvement in the manufacture of 

 candles resulted from combining these two matters, viz., stearic acid 

 of tallow with stearine of the cocoa-nut. It is found that stearic acid 

 of tallow burns with a somewhat red flame and is liable to smoke ; it 

 contains too large a quantity of carbon ; whilst the stearine of cocoa- 

 nut oil contains too much hydrogen, and burns with a white flame. 

 The effect of combining these two matters was to obtain a better flame 



