PHOSPHORUS

, a matter which shines, or even burns spontaneously, and without the application of any sensible fire.

Phosphori are either natural or artificial.

Natural Phosphori, are matters which become luminous at certain times, without the assistance of any art or preparation. Such are the glow-worms, frequent in our colder countries; lantern-flies, and other shining insects, in hot countries; rotten-wood; the eyes, blood, scales, flesh, sweat, feathers, &c, of several animals; diamonds, when rubbed after a certain manner, or after having been exposed to the sun or light; sugar and sulphur, when pounded in a dark place; sea water, and some mineral waters, when briskly agitated; a cat's or horse's back, duly rubbed with the hand, &c, in the dark; nay Dr. Croon tells us, that upon rubbing his own body briskly with a well-warmed shirt, he has frequently made both to shine; and Dr. Sloane adds, that he knew a gentleman of Bristol, and his son, both whose stockings would shine much after walking.

All natural Phosphori have this in common, that they do not shine always, and that they never give any heat.

Of all the natural Phosphori, that which has occasioned the greatest speculation, is the

Barometrical or Mercurial Phosphorus. M. Picard first observed, that the mercury of his barometer, when shaken in a dark place, emitted light. And many fanciful explanations have been given of this phenomenon, which however is now found to be a mere electrical effect.

Mr. Hawksbee has several experiments on this appearance. Passing air forcibly through the body of quicksilver, placed in an exhausted receiver, the parts were violently driven against the side of the receiver, and gave all around the appearance of fire; continuing thus till the receiver was half full again of air.

From other experiments he found, that though the appearance of light was not producible by agitating the mercury in the same manner in the common air, yet that a very fine medium, nearly approaching to a va- <*>uum, was not at all necessary. And lastly, from other experiments he found that mercury inclosed in water, which communicated with the open air, by a violent shaking of the vessel in which it was inclosed, emitted particles of light in great plenty, like little <*>ars.

By including the vessel of mereury, &c, in a receiver, and exhausting the air, the phenomenon was changed; and upon shaking the vessel, instead of sparks of light, the whole mass appeared one continued circle of light.

Farther, if mercury be inclosed in a glass tube, close stopped, that tube is found, on being rubbed, to give much more light, than when it had no mercury in it. When this tube has been rubbed, after raising successively its extremities, that the mercury might flow from one end to the other, a light is seen creeping in a serpentine manner all along the tube, the mercury being all luminous. By making the mercury run along the tube afterwards without rubbing it, it emitted some light, though much less than before; this proves that the friction of the mercury against the glass, in running along, does in some measure electrify the glass, as the rubbing it with the hand does, only in a much less degree. This is more plainly proved by laying some very light down near the tube, for this will be attracted by the electricity raised by the running of the mercury, and will rise to that part of the glass along which the mercury runs; from which it is plain, that what has been long known in the world under the name of the Phosphorus of the barometer, is not a Phosphorus, but merely a light raised by electricity, the mercury electrifying the tube. Philos. Trans. numb. 484.

Artificial Phosphori, are such as owe their luminous quality to some art or preparation. Some of these are made by the maceration of plants alone, and without any fire; such as thread, linen cloth, but above all paper: the luminous appearance of this last, which it is now known is an electrical phenomenon, is greatly increased by heat. Almost all bodies, by a proper treatment, have that power of shining in the dark, which at first was supposed to be the property of one, and afterwards only of a few. See Philos. Trans. numb. 478, in vol. 44, pa. 83.

Of Artificial Phosphori there are three principal kinds: the first burning, which consumes every combustible it touches; the other two have no sensible heat, and are called the Bononian and Hermetic Phosphorus; to which class others of a similar kind may be referred.

The Burning Phosphorus, is a combination of phlogiston with a peculiar acid, and consequently a species of sulphur, tending to decompose itself, and so as to take fire on the access of air only. This may be made of urine, blood, hairs, and generally of any part of an animal that yields an oil by distillation, and most easily of urine. It is of a yellowish colour, and of the consistence of hard wax, in the condition it is left by the distillation; in which state it is called phosphorus fulgurans, from its corruscations; and phosphorus smaragdinus, because its light is often green or blue, especially in places that are not very dark; and from its consistence it is called solid Phosphorus. It dissolves in all kinds of distilled oils, in which state it is called liquid Phosphorus. And it may be ground in all kinds of fat pomatums, in which way it makes a luminous unguent.—So that these sorts are all the same preparation, under different circumstances.

The discovery of this Phosphorus was made in 1677, by one Brandt, a citizen of Hamburgh, in his researches for the philosopher's stone. And the method was afterwards found out both by Kunckel, and Mr. Boyle, from only learning that urine was the chief sub-| stance of it; since then it has been called Kunckell's Phosphorus. It is prepared by first evaporating the urine to a rob, or the consistence of honey, and afterwards distilling it in a very s<*>rong heat, &c. See Mem. Acad. Paris 1737; Philos. Trans. numb. 196, or Abr. vol. 3, pa. 346; Mem. Acad. Berlin 1743.

Many curious and amusing experiments are made with Phosphorus; as by writing with it, when the letters will appear like flame in the dark, though in the light nothing appears but a dim smoke; also a little bit of it rubbed between two papers, presently takes fire, and burns vehemently; &c. By washing the face, or hands, &c, with liquid Phosphorus, they will shine very considerably in the dark, and the lustre will be communicated to adjacent objects, yet, without hurting the skin: on bringing in the candle, the shining disappears, and no change is perceivable.

Bolognian or Bononian Phosphorus, is a preparation of a stone called the Bononian stone, from Bologna, a city in Italy, near which it is found. This Phosphorus has no sensible heat, and only becomes luminous after being exposed to the sun or day light. For the method of preparing it, see the Mem. Acad. Berlin 1749 and 1750.

The Hermetic Phosphorus, or third kind, is a preparation of English chalk, with aqua fortis, or spirit of nitre, by the fire. It makes a body considerably softer than the Bolognian stone, but having otherwise all the same qualities. It is also callėd Baldwin's Phosphorus, from its inventor, a German chemist, called also Hermes in the society of the Naturæ Curiosorum, whence its other name Hermetic: it was discovered a little before the year 1677. See Acad. Par. 1693, pa. 271; and Grew's Mus. Reg. Soc. p. 353.

Ammoniacal Phosphorus, first discovered by Homberg, is a combination of quick-lime with the acid of sal ammoniac, from which it receives its phlogiston. Mem. Acad. Par. 1693.

Antimonial Phosphorus, is a kind discovered by Mr. Geoffroy in his experiments on antimony. Mem. Acad. Par. 1736.

Phosphorus of the Berne-stone, a name given to a stone from Berne, in Switzerland, where it is found, and which becomes a kind of Phosphorus when heated. Mem. Acad. Paris 1724.

Canton's Phosphorus, a very good kind, prepared by Mr. Canton, an ingenious philosopher, from calcined oyster shells. Philos. Trans. vol. 58, pa. 337.

Phopshorus Fæcalis, a very good kind, exhibiting many wonderful phenomena, and prepared, by Mr. Homberg, from human dung mixed with alum. Mem. Acad. Par. 1711.

Phosphorus Metallorum, a name given by some chemists to a preparation of a certain mineral spar, found in the mines of Saxony, and other places where there is copper. Philos. Trans. numb. 244, p. 365.

Phosphorus of Sulphur, a new-discovered species, which readily takes fire on being exposed to the open air, and invented by M. Le Fevre. Mem. Acad. Par. 1728.

, in Astronomy, is the morning star, or the planet Venus, when she rises before the sun. The Latins call it Lucifer, the French Etoile de berger, and the Greeks Phosphorus.