The coloured glasses which are sold in Paris for the purpose, are formed with facets on the outside, which not only produce the appearance of coloured flame, but also, according to the number of facets, the refraction and reflection of the light. Arches, pyramids, obelisks, &c. are lighted up in this manner.
The Pont Neuf, and the Seine in 1739, were illuminated at the time of the splendid exhibition of fire-works. It is unnecessary, however, to particularize on this head. We all remember the splendid illuminations in all our cities during the late war, which were indeed a true expression of our national and individual feeling. Illuminations, in this country, before that time were very rare; none we think since the peace of 1783, and the union under the federal compact.
Phosphuret of lime, of the size of peas, thrown into water, will afford, at short intervals, a brilliant flame of fire; for the phosphuretted hydrogen gas thus produced has the property of inflaming spontaneously in atmospheric air. Alcohol, containing sundry salts in solution, will give a flame of various colours, according to the salt it holds in solution. See [Alcohol.]
Illuminated works are much admired by the Italians, and particularly the Illuminated chandelier, which is considered a great addition to a collection of works. An illuminated chandelier is formed of thin wood with arms extending on each side. Holes are bored in the front of the branches and in the body, and also in the eagle (if it be added,) at top, and distant from each other about three inches. In these holes, we put illuminations, filled with white, blue and brilliant charge. Having fixed in the port-fires, they must be clothed with leaders, so that the chandelier and eagle may light together.
We may also observe, that, for the speedy lighting of a number of lamps, at one and the same time, quick-match enclosed in paper tubes has been used. This quick-match is sometimes made to communicate its fire to a sulphur match, prepared by dipping strands of cotton in melted sulphur, and from this to the lamp. Several methods are recommended for this purpose; one of which consists in dipping cotton wick in the oil of spike, and arranging it along the wicks of the different lamps, so that when inflamed the fire may pass rapidly from one lamp to another. In 1772, M. Renault, a Parisian, announced in the public papers, that he possessed a secret, by which he could light 2000 lamps in five minutes, by means of a match of communication.
We have some experiments and observations on coloured flame, by Mr. Morey, in his essay on heat and light, in the second volume of Silliman's Journal of Science and Arts, p. 120. The experiments are curious, and worthy of remark. If water, he observes, be put into one cylinder, and made to boil, and the steam be led to the bottom of another included cylinder, containing spirits of turpentine, the steam, when let out under a moderate pressure, carries off with it a sufficient quantity of the spirit to burn with a pleasant white flame, free from smoke; but if the pressure be increased, the flame will become in part or wholly blue. "Here," he adds, "as in many other experiments, I have noticed, that different coloured flames may be produced from the same materials—are the products of combustion different?" He further observes, that "if the steam of water, containing a small proportion of the vapour of rosin, be driven against iron, at or below a red heat, it burns with a pleasant blue flame, which will be extended some way back into the column of the vapour, intermixed with innumerable sparks of very white flame, evidently particles of the rosin. If the vapours, when the proportion of the rosin is very small, are made to pass between two plates of iron, at or near a red heat, they can be inflamed on the opposite sides of the plates, and will then, sometimes, burn with an entirely blue flame, although the vapour can not be inflamed, without the intervention of the plates." He states other experiments, made with tallow and steam, producing a blue flame. The blue colour seems to be owing to the pressure made use of; for, in his second communication, (page 122, of the same volume), he mentions white flame being produced by the vapour of water; and when it is in a sufficient quantity, there is no smoke. If too great, combustion ceases. Speaking of the colour of the flame, produced by mixed vapours, (of the combustible and water), such as blue, blue and white, white and intense white, he adds, that they may be imitated, at pleasure, with the patent lamp stove, by burning tar, pitch pine, or mineral coal and water. Newly made charcoal will take up about three times its weight of water. "Sand, ashes, or fine clay," he observes, "answers well for mixing with the tar, &c. If the latter be made into a paste with equal parts of spirit of turpentine and water, and cold lumps of it, of a conical form, be placed on a table, and a flame applied, the vapours burn without smoke for a short time, &c. If enclosed in a tin cylinder, and the vapour be made to issue through small holes at the top, placed as before stated, or on a plate over a chafing dish of coals, it burns with a very bright light, free from smoke. If the cylinder be tight at the top and the vapour be led from the inside at the top, down and through the bottom, and there be made to issue in an oblique direction, and from a number of small openings, it will burn with a beautiful flame and supports and regulates, very accurately, its own evaporation. The oblique direction carries the heat, in part, beyond the cylinder, when the evaporation is too great.
"Every effect may be produced in consuming the smoke, and giving an intense white flame, by using a certain proportion of water, intimately blended or mixed with these vapours, that can be from an access of oxygen furnished, by creating a very strong current of air, with a high flue." The description of Morey's lamp stove, may be seen in the same work. The steam, he observes, may be furnished by a small tin boiler, and directed to or near the bottom of the tar. An intense white flame free from smoke, may be thus produced from tar, rosin, rough turpentine or the spirit, alcohol, oil, fat, tallow, mineral coal, pitch pine wood, and the knots, birch bark, and pumpkin, sun-flower, flax, and other seeds. With regard to pine wood, he adds, it is the easiest managed, evaporates at a lower temperature, consumes a greater proportion of water in its combustion, contains the water within itself, and gives a brighter light than common candles or lamps, and without smoke. The more volatile parts are evaporated at a temperature below that of boiling water, and burn well with three parts of the vapour of water; the flame then, however, is nearly blue. Observations on the application of this mode of producing light and heat, may be seen in Silliman, p. 131, &c. It appears, that Gay-Lussac (Annales de Chimie, for June, 1819,) has commented on Mr. Morey's plan.
Professor Hare (Silliman's Journal, vol. 2d, p. 172) also observes, that the flame of hydrogen gas is rendered luminous, like that of oil, by adding a small quantity of oil of turpentine to the usual mixture for generating this gas; and that the addition of 1/17 of the same fluid to alcohol, will give it the property of burning with a highly luminous flame; and there is a certain point in the proportions, at which the mixture burns without smoke, like a gas light. In the first instance, he observes, when the ingredients are at the proper temperature, the light is greater than that produced by carburetted hydrogen gas. Speaking of this application of spirits, the professor judiciously adds: "It might be serviceable to morals, if the value of this article could be enhanced by a new mode of consumption." We find, also, that the effect of vapour on flame has been noticed by Dr. Dana, in the same Journal, vol. 1, p. 40; by which it appears, that when a jet of steam is made to pass into a charcoal fire, the vividness of the combustion is increased, and also the low attenuated flame of the coal; that it prevents the smoke of a common oil lamp, and makes the flame brighter; that the flame of spirit of turpentine, which is usually dull and reddish, is rendered bright, and no smoke is formed; or when the vapour of both are made to issue together from the same orifice, and inflamed, no smoke appears; that a jet of steam, thrown into the flame of a spirit of wine lamp, or into flames which evolve no smoke or carbonaceous matter, produces the same effect as a current of air; but that, in all flames which evolve smoke, steam produces an increased brightness and a more perfect combustion. Dr. Dana further suggests, that steam might be introduced into the flames of street lamps, which might be so contrived as to keep water boiling, to produce the steam, and thereby cause a more perfect combustion, and a greater quantity of light from the same materials.
Count Rumford has shown, that the quantity of light, emitted by a given portion of inflammable matter in combustion, is proportional, in some high ratio, to the elevation of temperature; and that a lamp, having many wicks near each other, so as mutually to increase their heat, burns with infinitely more brilliancy than the Argand lamps in common use. To measure the proportional intensities of two or more lights; place them a few inches asunder, and at the distance of a few feet or yards from a screen of white paper, or a white wall. On holding a small card near the wall two shadows will be projected on it, the darker one by the interception of the brighter light, and the lighter shadow, by the interception of the duller light. Bring the fainter light nearer to the card, or remove the brighter one further from it, till both shadows acquire the same intensity. Measure now the distances of the two lights, from the wall or screen, square them, and you have the ratio of illumination. Thus, if an Argand flame and a candle, stand at the distances of 10 feet and 4 feet, respectively, when their shadows are equally deep, we have 102 and 42, or 100 and 16, or 61/4 and 1, for their relative quantities of light.
The author of the Dictionnaire de l'Industrie, vol. iii, p. 365, in treating on the subject of illumination, mentions different modes of illuminating, both with and without transparencies. We know that various mixtures will produce different coloured flame. Thus, arsenic will burn with a beautiful white flame in oxygen gas; iron and steel will burn also, affording a brilliant light; phosphorus and charcoal with a white, and sulphur with a beautiful blue flame; zinc with a green colour, &c.