Notwithstanding, therefore, the competition of gas and petroleum, and, it may be added, possibly of the electric light, there seems no reason for believing that the candle trade will do other than increase with the needs of the population, and will continue to repay every effort devoted to its improvement which is founded upon truly scientific and sound commercial principles.
Night-lights.—The making of night-lights is an important branch of candle manufacture. In 1877, Price's Caudle Company, who enjoy almost a monopoly of the production of these useful articles, turned out 32 millions of them. There are two distinct kinds of night-light ; the common form, so long known as Child's, from the inventor, whose son now manages this department of Price's Candle Company's factory, and the Company's new patent night-light. The former are made by running molten fatty matters into little wooden cases, which are the result of a series of operations. Balks of timber, free from knots, are the foundation of the manufacture ; the best American pine is preferred, but it is now becoraing scarce and dear, and the so-called " tulip-wood " has often to be substituted for it. The balks of timber are brought under a huge planing machine, which shaves eft' beautifully even slices, no thicker than stout paper. These are used as well for the boxes iu which the night-lights are packed for transport as for the cases of the night-lights themselves. It is perhaps a little out of order, but at any rate it is convenient, here to complete the account of the manufacture of the packing boxes. The slices of wood are cut iuto rectangular form of the required size, and corresponding sheets of tough, but very thin, paper are pasted over them, by boys, at great speed. In this condition, they are pressed, to ensure adhesion, and Etre then taken to a machine for the purpose of having incisions made in them, where the edges are to be turned up to form the sides and ends. The cutters of this machine are so beautifully adjusted, that they completely sever the wood without so much as scratching the paper backing, which remains to form the hinges or angles. The satne thin slices of wood are used in making the night-light cases. The slices, each of a size to fortn about a dozen cases, are coated with paper. This, like all the remaining processes in the tnanufacture of Child's night-light cases, is performed in a most dexterous manner by girls. The slices are placed on a table before a girl, who with one hand pastes a. printed yellow label on the wood, while with the other hand she costs the paper label with gum, which gives it a glazed appearance, and st the same time renders it waterproof, the latter being an important consideration, as the light has to be burnt in a saucer of water. The double slices are immediately rolled to
a given diameter, and are then carried on trays to a heated room to dry. After drying, each roll is subdivided into the proper number of cases, by means of a lathe, at the rate of 150 per minute. Next they are bottomed with cardboard, by means of a fitting stick, and an aperture is punctured in the centre for the introduction of the wick. This is provided with a tiny square tin-foil sustainer, which is secured to the ease by means of a single drop of wax. The cases, thus prepared, are placed on trays to be filled. This operation is entrusted to boys, who manifest a skill and exactitude quite astonishing, and have proved themselves superior to any mechanism which has yet been tried for the purpose. The creamy fat is poured from ,,, can with a narrow straight spout, sufficient being tipped at one operation into each case to exactly fill it and no more. When cool, the exterior of each case is soraped with a blunt knife to remove accidental splashes, and the lights are ready for packing in the boxes already alluded to.
The new patent night-lights differ from the foregoieg, not only it, being made front very much better materials, but also in the method of manufacture and mode of burning. Cases are dispensed with, a,nd the fatty material, usually derived from palm oil, is moulded to the required shape by being run into a frame, which consists of a number of moulds or cups securely fitted to a bcd of iron or wood. Into these, the melted material is poured and left to cool. When culd, the excess of fat is scraped off with a blunt tool, and the night-lights, ready punctured for the insertion of the wick, Etre lifted out by a screw. The wicks are introduced by boys. On each wick, cut to the proper length, is threaded a tiny square of tin-foil, which is to serve as a support for it during the latter stage of the combustion of the light ; the wick is then thrust through the little disc of opaque white fat, aud is secured by a cleat effected by R sharp blow on a miniature verticEt1 anvil. The rapidity and precision with whioh the lads perform this operation is something to admire. The lights are now ready for burning, for which purpose they are placed without water ie little glass cups. Night lights are made of various sizes, calculated to burn for six, eight, or ten hours.
(See Glycerine ; Oils ; Ozokerit ; Paraffin ; Photometry ; Soap ; Spermaceti ; Wax.)