Formula Ph. Equivalent = 32.

1. History

Phosphorus was discovered in 1669, by Brandt, alchemist of Hamburg. He was engaged in researches on the philosopher's stone, or the art of converting common metals into gold. Brandt thought, that by mixing urine with the metals that he wished to transmute, he should succeed better; but instead of obtaining what he was searching for, he discovered a new body, luminous by itself, burning 2 with an energetic power. It was the phosphorus. Surprised by the appearance of this new body, he sent a specimen to Kunckel, a German chemist, who showed it to Kraft, of Dresden. This latter found it so marvellous, that he immediately started for Hamburg, with the intention of buying the secret of its preparation ; and, accordingly, he bought it for two hundred dollars, on condition that the secret would not be revealed. Kunckel, wishing to know it, and seeing that Kraft would not reveal it to him, resolved to discover it by experimenting himself, and, after many trials, he succeeded in 1674.

However, the process of preparation was kept secret till 1737, at which epoch, a stranger coming to Paris, made some of it before four commissioners named by the Academy of Sciences, Hellot, Dufay, Geoffroy, and Duhamel. When the preparation was made public, Hellot described it, with details, in 1737,* and Rouelle repeated it in his public lectures of the same year. The process consisted in evaporating to dryness, putrefied urine, and heating strongly the residue in an earthen retort, the neck of which communicated with water.

* Memoire de l'Academie des Sciences, for 1737.

Phosphorus was prepared by this process for some time; and a few years after, by the advice of Margraff, a salt of lead was added to it. Notwithstanding this useful addition, phosphorus was so rare that it passed for an object of curiosity, to be found only in chemical laboratories.

In 1674, Gahn discovered it in bones, and with Scheele published a process which permitted of obtaining it in considerable quantities. It is this same process, slightly modified, which is now followed.

Phosphorus becoming more common, chem-ists could study its properties. The most remarkable works on this subject are those of Pelletier, who combined it with sulphur and some metals; Lavoisier, who discovered its combinations with oxygen; Dulong and Davy studied its different acids, and Berzelius not only examined them, but also their combinations with bases.

2. Physical Properties

Phosphorus is solid, insipid; pure, it is so flexible that it can be bent seven or eight times without breaking. One six hundredth part of sulphur is sufficient to render it brittle.

The nail scratches it easily, the knife cuts it without any difficulty.

Its specific gravity = 1.77. Its odor is weak, and similar to hydrogen gas or arsenic in vapor. Sometimes it is transparent and colorless, sometimes transparent and yellowish, sometimes half transparent as horn, sometimes black and opalescent.

In the dark it is always luminous, provided it has the contact of the air; from that property, its name of two Grecian words, , light, and bearing.

4. Natural State

Since phosphorus burns with so much facility, it does not exist pure in nature; and in which it has been met only in combination with other bodies, viz,, with oxygon, and me-tallie oxides, in some phosphates, particularly the phosphate of lime, which forms the solid basis of bones of animals, in the milt of the carp, and a part of the cerebral matter and nerves, substances composed of oxygen, carbon, nitrogen, and phosphorus.