It is obvious, that if the brimstone is impure, the effect of it in fire-works will be imperfect. Flowers of sulphur, however, may be almost always depended on. In all artificial fire, in which sulphur forms a part, the flame is more clear, as the sulphur is pure.
Several modes are recommended for the separation of sulphur from charcoal, in gunpowder, which may be seen by referring to the analysis, or chemical examination of gunpowder.
Sulphur constitutes one of the ingredients, generally speaking, of incendiary compositions, used for military purposes, and, in such cases, is usually mixed with pitch, tar, saltpetre, and sometimes gunpowder. It is said to be one of the substances, which entered into the composition of the ancient and celebrated Greek fire; but the principal character of which, that of burning in water, was owing to the presence of camphor. This substance, associated with sulphur, pitch, and nitre, forms one of the most effective incendiaries of all military fire-works. For such purposes, it is hardly necessary to add, that the common roll brimstone is sufficiently pure.
As to the mode of preparing these works, the custom is to melt the resinous substances first, then to add the sulphur, and finally the saltpetre; and after the whole are melted and thoroughly mixed, to remove the pot from the fire, and add gradually the gunpowder. If a carcass is to be made, tow or hemp, or untwisted rope, is immersed in the composition while hot, and taken out and formed into a ball of the size required. Rope, treated in the same manner, with the same composition, will make a more active tourteaux than the common kind. (See Carcass and Tourteaux.)
All oils, whether expressed or essential, can dissolve sulphur. To make this solution, the oil must be poured on the sulphur, and sufficient heat applied to melt the substance. While the oil dissolves the sulphur, it acquires a reddish or brown colour, an acrid, disagreeable taste, and a strong fetid smell, somewhat hepatic, resembling that of oil with sulphuric acid.
Sec. V. Of Phosphorus.
We mention this substance, because it is used in some experiments, although not in extensive fire-works. It is a very inflammable substance, inflaming either by friction, or an increase of temperature. It produces a most brilliant fire, and when mixed with some substances, exhibits very pleasing phenomena. It usually comes to us in sticks, which must be constantly kept in water to prevent its inflammation. Phosphoric matches, phosphoric fire-bottles, &c. are made of it. These are made in various ways. Phosphorus and sulphur melted together in a small phial, forms the fire-bottle, or some add a portion of lime. A sulphur-match dipped in this mixture and gently rubbed, immediately inflames. They do not last any time, in consequence of the acidification of the phosphorus. Phosphoric tapers are usually made with a glass tube, on the breaking of which, it inflames. When rubbed upon a wall in a dark room, it appears very luminous. Dissolved in ether, and poured upon boiling water in the dark, the vapour as it ascends appears remarkably luminous, and has a pleasing effect. Dissolved in oil, as olive-oil, it forms the phosphorized oil, which may be rubbed on the face and hands without injury. This oil has the same appearance in the dark. The time of night may be known by the light it produces. When mixed with nitrate of silver, sulphuret of antimony, sulphur, chlorate of potassa, &c. and struck with a hammer, it produces an explosion more or less loud. A variety of explosive compounds may be made with it, but they must be used with great care.
When combined with hydrogen, it inflames spontaneously when brought in contact with atmospheric air. It inflames also in chlorine gas. It is supposed to be the cause of the ignes fatui, or Will-with-the-Wisp. The formation of phosphoretted hydrogen gas may be shown in a variety of ways, as the following: throw some pieces of phosphuret of lime into water, and bubbles of gas will rise, which will take fire on coming to the air; or, put into a flask some phosphorus, iron or zinc filings, water, and sulphuric acid, and the gas will be generated; or, introduce into a small retort, a solution of potassa, and a piece or two of phosphorus, and apply heat, immersing the beak of the retort in a basin of water, the gas will pass over, and inflame as it comes to the surface of the water. In all these experiments, the water is decomposed; its oxygen goes to a part of the phosphorus in the first experiment, and the hydrogen of the water then unites with another portion of phosphorus, which is then evolved; in the second experiment, the oxygen oxidizes the metal, and the hydrogen dissolves a part of the phosphorus; and in the third experiment, the phosphorus unites with the potassa, forming a phosphuret, which decomposes the water, the hydrogen of which passes off in combination with some of the phosphorus, forming the phosphuretted hydrogen gas.
The cause of the spontaneous combustion is, that the oxygen of the atmosphere unites with the hydrogen and the phosphorus, and forms water and phosphoric acid; the latter producing a beautiful corona as it rises in the air. The heat and light given out proceeds as well from the oxygen gas, as from the phosphuretted hydrogen gas. When saturated with oxygen, it is no longer inflammable.
There are some other experiments which can be made with this singular substance.
It was formerly obtained from urine, as that fluid contains some phosphoric salts. It is now prepared from bones. These are burnt to an ash, and diluted sulphuric acid is poured on it; the phosphoric acid it contains is then disengaged, and remains in the fluid. The sulphate of lime is then separated, the fluid boiled to dryness, and the dry mass is mixed with charcoal, and distilled in the open fire.
The phosphoric pencil, for writing on a wall, paper, &c. to be luminous in the dark, is nothing more than a bit of phosphorus put into a quill. It must be kept in water, and when used, frequently dipped in water, to prevent its taking fire.
The phosphoric stone of M. Bucholz, described in the Archives des Découvertes, ii, p. 109, is a phosphuret of magnesia, prepared by melting thirty grains of phosphorus in a small flask, and adding twenty or thirty grains of calcined magnesia. Although this process is given by Bucholz, yet, as it is difficult to prevent the inflammation of the phosphorus, the best mode would be to bring the vapour of phosphorus in contact with magnesia, in the same manner as in preparing phosphuret of lime.
The pyrophorus of Wurzer is nothing than a phosphuret of lime. It is prepared by taking two parts of pulverized quicklime, and one part of phosphorus; introducing them into a bottle, and covering it with three parts of quicklime, leaving one-third of the bottle empty; then putting the bottle into a crucible surrounded with sand, previously stopping the mouth with clay, and applying heat. Remove the phial when the phosphorus appears to sublime of a red colour. When the bottle is opened it becomes luminous, and brought out it inflames.
Phosphorus in the state of acidification, and united with lime, is found in abundance. Whole mountains in the province of Estremadura in Spain, are said to be composed of this combination. According to Mr. Bowles, this stone is whitish and tasteless, and affords a blue flame without smell when thrown upon burning coals. Mr. Proust observes, that it is a dense stone, not hard enough to strike fire with steel, and is found in strata, which always lie horizontally upon quartz, and which are intersected with veins of quartz. He adds, that it does not decrepitate on burning coals, but burns with a beautiful green light. This stone is the common phosphorite. It contains, according to Klaproth, 32.25 per cent. of phosphoric acid.
Several substances are known under the name of phosphorus, although they do not contain it, such as Baldwin's phosphorus, or ignited muriate of lime, Canton's phosphorus, or oyster-shells calcined with lime, and Bologna phosphorus, or calcined sulphate of barytes.
Sec. VI. Of Charcoal.
Charcoal performs an important part in all the various kinds of fire-works. The facility with which it decomposes nitric acid, when it is combined with salifiable bases, as with potassa in saltpetre, and its action in all cases wherein nitre is concerned, are sufficient examples of its effect.
Pure carbon is the diamond. It affords by combustion in oxygen gas, the same gas as common charcoal, when charcoal is burnt in oxygen, or in atmospheric air. This gas is carbonic acid, or fixed air. Charcoal has been considered a long time an oxide of carbon,