Candle, a small cylindrical body of tallow, wax, spermaceti, or other fatty substance, formed on a loosely twisted wick, used for a portable light. Although in the English translation of the Bible we find occasional mention of candlesticks, it appears that these were really lamps for burning olive oil, and not the supports for what we now call candles. Nor did the ancient Greeks and Romans possess any nearer approach to these useful inventions than the rude torches prepared by dipping strips of papyrus or rushes into pitch, and coating them with wax. In the middle ages, according to Fos-broke, this kind of candle was in use, some of them being of 50 lbs. weight, and containing a twisted tow wick. The tallow prepared from the fat of animals afterward came to be used for the manufacture of candles, and at a still later period the similar product, called spermaceti, of the fluid fat of the whale. The vegetable kingdom, too, has been largely drawn upon to furnish from its oils, as those of the palm especially, and of the cocoanut, a solid material for this same use.
The mineral kingdom, at last, has been made to yield from the bituminous coals, in the substance paraffine, another excellent material for candles. - Common dipped candles have long been made by introducing wicks of cotton yarn into warm semifluid tallow, and, when they have become saturated, taking them out and suspending them by one end till the tallow cools; they are then dipped again, and again cooled, and so by each dipping accumulate more tallow, till they attain the required size. A mixture of mutton suet and beef fat is preferred to either alone. Instead of the old-fashioned method of dipping by hand, a simply contrived machine has been devised, consisting of an upright revolving post, which carries 12 horizontal arms, at the end of each of which is attached a frame of six rods; from each of these hang 18 wicks, making in all 1,296. As the post is turned round, each arm comes in succession over the reservoir of tallow. The frame upon it is arranged so that the wicks can be let down into the tallow. Thus one set after another receives an application of tallow, and is cooled as it revolves around, before its turn comes for another dip. "When the weather is not very warm, the whole can be completed in about two hours.
An improvement upon the dipping process was the substitution of cylindrical moulds of the size of a candle, made of tin or pewter, and a number of them arranged in a frame: moulds of glass have recently been substituted for those of metal. A wick is secured through the centre of each mould, the tallow is poured in, and the wick being stretched tight, they are set away to cool. Wax is often added to tallow, to give it greater hardness; and it is also at times introduced first into the moulds, and by turning these round made to line them entirely, leaving a smaller cylindrical cavity, into which the tallow is afterward poured; the candle is thus made to have its exterior part of wax. - The greatest improvements in the manufacture of tallow candles have resulted from the investigations of M. Chevreul into the composition of animal and vegetable oils and fats. In 1813 he announced the discovery that most of these bodies consist of a number of compounds of different acids with one base, which he called glycerine. Combined with stearic acid, it forms stearine; with oleic acid, oleine; and with palmitic acid, palmitine. These bodies are called glycerides.
Oleic acid is a fluid oil, which, according to its proportion in combination with the other solid acids, gives fluidity to the mass, and the tendency to run in the candles. Glycerine, the base, is a sweet sirupy substance, which adds little to the inflammability of the stearic and margaric acids with which it combines. By removing it from these acids, and then expressing from them the oleine, an excellent material for candles is obtained, hard and firm, and almost equal to those made of spermaceti. - The best candles in general use in this country are made of spermaceti. This substance, which is fluid in the whale, becomes when taken from the animal a white crystalline mass, composed of a liquid oil and a solid matter, which is the pure spermaceti. The oil is removed by first straining off so much as will pass through the bags used as filters. The sperm is next placed in hempen bags and subjected to machine pressure. After this the substance is reduced to powder, placed in other bags, and pressed much more powerfully than before. The spermaceti cakes are next melted and boiled with a soda ley, just sufficient in quantity to form a soap with the oil in the sperm, without acting upon the solid matter.
The soap floating upon the surface is skimmed off, and the sperm is set to crystallize in moulds; only, however, to be again ground, pressed, boiled with an alkaline ley, washed with water, and moulded into blocks. From these blocks the candles are moulded as may be convenient. The moulds require to be heated to the temperature of the melted sperm, and slowly cooled after filling to prevent crystallization of the material, and the same precaution is required with stearic acid candles. The English are in the habit of adding about 3 per cent, of wax, which answers the same purpose of preventing the material from assuming the brittle, crystalline structure. They, and the French also, sometimes introduce coloring matters into the candles, in so small quantity as not to destroy their beautiful transparency, nor to affect the brilliancy of their light. Gamboge gives to them a yellow tint like wax; chromate of lead is used in France for this color, carmine for red, and Prussian blue for blue. - Wax candles are now little used compared with the other kinds. They are made by dipping, and by pouring the melted wax over the wicks. The shape is given during the process and at its close by rolling the candles between marble slabs.
The candles are sometimes shaped by-drawing them through a machine made for the purpose, as wire is drawn. There is a difficulty in moulding wax candles, owing to the substance adhering to the interior surface of the mould. Moulds of glass, however, have been successfully used, greater strength and security being given to them by incasing each one in a tube of gutta percha. By dipping them for an instant in hot water, the glass expands sufficiently to free the candle, which should be extracted as the mould comes out of the water. Wax requires smaller wicks than other candles, and they should be made of twisted Turkey cotton unbleached. The large wax candles used in Roman Catholic churches are made by rolling a sheet of wax placed upon a slab over the wick laid down upon it, and then giving shape to them by rolling in the usual way between marble slabs. Coloring matters similar to those used for coloring spermaceti candles may first be melted into the wax. - Paraffine candles are not yet prepared upon a large scale, but the practicability of obtaining from bituminous coals a large amount of oil from which this beautiful material for candles may be extracted, has been fully established.
It is a true chemical compound of carbon and hydrogen, in those atomic proportions which appear most suitable for producing the best light. - Candle wicks have been the subject of special attention on the part of the manufacturers. It is found that the more perfect the wick, and the better adapted it is to the particular kind of candle, the more brilliant is the light and the less the consumption of material. The coarse threads used for tallow candles raise the melted grease to very little height, and are soon covered with a burr of carbonaceous matter, which must be removed by frequent snuffing. Wicks of finer threads have a greater capillary action, and require less snuffing. So long as the threads of the wick remain in the body of the flame, they are protected from the action of the oxy-' gen of the air, and the material is charred without being consumed. By turning the top of the wick to one side, so as to project from the flame, the light is no longer obscured by this burr, which soon disappears by its combining with oxygen. The plaited or braided wicks were contrived to effect this result, the plaits opening at the top and spreading out to the edge of the flame.
A twist has been given to wicks by winding them around a cylinder, and in this state saturating them with the melted material; after being drawn out and stretched in the candle, they still retain the tendency to assume the spiral form, and as the candle is consumed, the end of the wick coils out from the flame and is burned without obstructing the light. Wicks made of two parts twisted in opposite directions and wrapped around with a fine thread are also used. Other expedients have been devised to effect the same purpose; and ingenious and expensive machinery is in use in large candle factories for the manufacture of wicks alone.