A substance which shines by its own light. The discovery of this singular substance was accidentally made in 1677, by an alchemist of Hamburgh, named Brandt, when he was engaged in searching for the philosopher's stone. Mr. Boyle is also considered to have discovered it; he communicated the process to Godfrey Hankwitz, an apothecary of London, who, for many years, supplied Europe with phosphorus; and hence it went under the name of English phosphorus. In the year 1774 the Swedish chemists, Gahn and Scheele, made the important discovery, that phosphorus is contained in the bones of animate; and they improved the process for procuring it. The most convenient process for obtaining it seems to be that recommended by Fourcroy and Vauquelin, which we shall transcribe. Take a quantity of burnt bones, and reduce them to powder: put 100 parts of this powder into a porcelain or stone-ware basin, and dilute it with four times its weight of water; 40 parts of sulphuric acid are then to be added in small portions, taking care to stir the mixture after the addition of every portion. A violent effervescence takes place, and a great quantity of air is disengaged. Let the mixture remain for twenty-four hours, stirring it occasionally to expose every part of the powder to the action of the acid.
The burnt bones consist of the phosphoric acid and lime; but the sulphuric acid has a greater affinity for the lime than the phosphoric acid. The action of the sulphuric uniting with the lime, and the separation of the phosphoric acid, occasion the effervescence. The sulphuric acid and the lime combine together, being insoluble, and fall to the bottom. Pour the whole mixture on a cloth filter, so that the liquid part, which is to be received in a porcelain vessel, may pass through. A white powder, which is the insoluble sulphate of lime, remains on the filter. After this has been repeatedly washed with water, it may be thrown away; but the water is to be added to that part of the liquid which passed through the filter. Take a solution of sugar of lead in water, and pour it gradually into the liquid in the porcelain basin; a white powder falls to the bottom, and the sugar of lead must be added so long as any precipitation takes place. The whole is to be again poured upon a filter, and the white powder which remains is to be well washed and dried: the dried powder is then to be mixed with one-sixth of its weight of charcoal powder.
Put this mixture into an earthenware retort, and place it in a sand bath, with the beak plunged into a vessel of water; apply heat, and let it be gradually increased till the retort becomes red hot. As the heat increases, air-bubbles rush in abundance through the beak of the retort, some of which are inflamed when they come in contact with the air at the surface of the water. A substance at last drops out similar to melted wax, which congeals under the water; this is phosphorus. To have it quite pure, melt it in warm water, and strain it several times through a piece of chamois leather, under the surface of the water. To mould it into sticks, take a glass funnel with a long tube, which must be stopped with a cork; fill it with water and put the phosphorus into it: immerse the funnel in boiling water, and when the phosphorus is melted and flows into the tube of the funnel, then plunge it into cold water; and when the phosphorus has become solid, remove the cork and push the phosphorus from the mould with a piece of wood. Thus prepared, it must be preserved in close vessels containing pure water. When phosphorus is perfectly pure it is.semi-transparent, and has the consistence of wax: it is so soft that it may be cut with a knife.
Its specific gravity is from 1.77 to 2.03. It has an acid and disagreeable taste, and a peculiar smell, somewhat resembling garlic. When a stick of phosphorus is broken, it exhibits some appearance of crystallization. The crystals are needle-shaped, or long octahedrons; but to obtain them in their most perfect state, the surface of the phosphorus, just when it becomes solid, should be pierced, that the internal liquid phosphorus may flow out, and leave a cavity for their formation. When the phosphorus is exposed to the light it becomes of a reddish colour, which appears to be an incipient combustion. It is therefore necessary to preserve it in a dark place. At the temperature of 90° it becomes liquid; and if air be entirely excluded, it evaporates at 219°, and boils at 554°; at the temperature of 43° or 44° it gives out a white smoke, and is luminous in the dark; this is a slow combustion of the phosphorus, which becomes more rapid as the temperature is raised. When phosphorus is heated to the temperature of 148°, it takes fire, burns with a bright flame, and sends out a great quantity of white smoke.
Phosphorus enters into combination with oxygen, azote, hydrogen, and carbon; it is soluble in oils, and, when thus dissolved, forms what has been called liquid phosphorus, which may be rubbed on the face and hands without injury; it dissolves, too, in ether, and a very beautiful experiment consists in pouring this phosphoric ether in small portions, and in a dark place, on the surface of hot water. The phosphoric matches consist of phosphorus, extremely dry, minutely divided, and perhaps a little oxygenized. The simplest mode of making them is to put a little phosphorus, dried by blotting-paper, into a small phial; heat the phial, and when the phosphorus is melted, turn it round, so that the phosphorus may adhere to the sides. Cork the phial closely, and it is prepared. On putting a common sulphur-match into a bottle, and stirring it about, the phosphorus will adhere to the match, and will take fire when brought into the air.