From an experiment which we have witnessed with spermaceti candles, made by Mr. Miller according to the plan described, they appear to answer the purpose intended.

Mr. John Murray, in a letter to the editor of Brewster's Journal, states that tallow candles may be materially improved by previously steeping the cotton wicks in lime water, in which there has been dissolved a considerable quantity of the nitrate of potass. The chlorate of potass is preferable to the nitrate, but the great expense of the former salt precludes its employment on the large scale. The wicks should be well dried before the tallow is put to them. By this process, Mr. Murray states that the candles afford a purer flame and a more brilliant light; the combustion of the wick is so complete as to render the snuffing of them nearly superfluous; and that they do not run or gutter.

With similar objects in view, Mr. William Palmer, of Wilson-street, Finsbury-square, London, obtained a patent, dated 10th August, 1830. He applies to about a tenth portion of the strands composing the wick, a quantity of bismuth in a finely divided state, or else the nitrate, or any other similar preparation of bismuth. The portion of wick thus prepared is to be surrounded with more strands, till it becomes half the thickness required for the wick. It is then to be cut into pieces, corresponding in length with twice that of the candle for which it is intended. The wick is next twisted spirally round a thick wire in contrary directions, a notch being made in the lower end of the wire to receive the middle of the wick; and the upper end is bent into a rectangular loop, to retain the two ends of the wire together, and to facilitate its removal when the making of the candle is completed, which is to be effected by either moulding or dipping in the usual manner. The combustion of the wicks of candles manufactured in this way, with a portion of bismuth in combination with the wick made of the double spiral form, causes the two upper extremities of the spiral, in the act of burning, to curl over to the opposite sides of the candles, where they are accessible to an additional quantity of oxygen, and the combustion is in consequence so intense as to leave no carbonaceous matter to impede the light, or to require removal by snuffers.

We shall close our article on this subject by the translation of a French Brevet d' Invention, granted to M. Lorraine, of Paris, for the manufacture of perfumed imitative wax candles, which we think is calculated to afford some useful practical hints to the British tallow chandler. " Candles made of tallow only," observes M. Lorraine, " are unctuous, opaque, greasy, little sonorous, especially in summer, liable to run or gutter, and readily acquiring a rancid smell. These inconveniences are avoided by putting fat, which has been melted and run into cakes, to ferment in a stove where the heat is moderate; this fat distils, and throws off an oily liquor, which is removed with a piece of linen or a sponge. To free the grease from the fleshy and fibrous parts by which it is accompanied, it is first chopped, and after being washed in several waters, it is boiled with a given quantity of Roman alum. The alum soon separates and destroys the heterogeneous parts, and we obtain a pure clear fat, which will last a very long time. The fat chopped and melted, is run into buckets full of water distilled from aromatic simples, such as lavender, thyme, rosemary, etc. The fat and water are beaten together with a spatula, to effect an union.

After forty-eight hours the fat is separated from the water, by means of a water bath; the water alone is disengaged, and the aromatic and odoriferous parts remain incorporated with the fat. To complete the purification, the fat is liquefied and scummed, till no foreign substance nor water remains: this will be known by the limpid state of the fat, which then yields only a pure white scum. Still greater purity is obtained by a second quantity of alum incorporated with the tallow. Before casting or running the candles, a composition is made of half wax and half spermaceti, which serves to prepare the wicks. This composition, harder and more cohesive than the tallow, .lakes the candles less subject to gutter, to become firmer, last longer, and require less snuffing. At the moment of removing the pure liquefied tallow from the fire to cast the candles, a certain quantity of gum Arabic, dissolved in water, and united with a small quantity of wax and alum, is incorporated with it The whole are beaten together; and when the tallow has settled well, and cooled to a certain temperature, it is poured into the moulds.

By this preparation, in proportion as the cooling takes place, the foreign substances proceed to, and fix at the surface of the candles, forming a kind of covering pleasant to the touch, like wax candles. This covering also prevents the candles from guttering, and enables a person to handle and even rub them without greasing the fingers, and without communicating any other smell than that of the aromatics entering into the composition. The last operation for preventing the guttering of the candles when burning, and giving more solidity to them, is to prepare some glover's size very weak, and boiled with another quantity of gum and alum, and to pass a hair pencil dipped in this size, all over the candles, and the next day after they may be used. Candles prepared in this way are clear, transparent, sonorous, and last longer than others; they feel like bougies, and have the colour of pure wax."