Phosphorus, a term gene-raily given to such bodies as are luminous in the dark, without emitting heat or flame.

According to modern chemists, phosphorus is a simple, inflammable substance, which cannot be decomposed : when pure, it is transparent, and of a whitish colour ; being slightly tenacious, and fusible in a degree of heat inferior to th3t of boiling water. It constitutes a part of all organized bodies, whether of the animal, vegetable, or mineral kingdom. Thus, if wood be decomposed by putrefaction, in a certain degree of heat and moisture, then broken into fragments, and exposed to the oxygen of the atmosphere, it will become luminous in dark places. Putrescent veal also shines under similar circumstances; and likewise the sea-weeds usually employed in packing oysters.

The existence of phosphorus in vegetables, was first ascertained by M.MargraaF, who observed, that farinaceous grains, when exposed in close vessels to an intense heat, in a peculiar degree possessed this property of emitting light. It has, farther, been discovered in sugar; gum-arabic; flour; dung: urine; bone-ashes; and in every other animal and vegetable substance ; by the processes adopted in preparing the artificial phosphori of Homberg, Kunkel, and other chemists.

Properties o/Phosphorus :- Characters drawn on paper with solid phosphorus, will appear like a flame in the dark ; though, in the light, a dense smoke only will be perceptible : and, if such paper be held near the fire, the letters will immediately become black, and continue to be as legible as those formed with ink. Great caution, however, ought to be observed in making such experiments; because, if a particle of phosphorus be rnbbed between two papers, they will immediately take fire, which cannot be easily extinguished; hence it will be advisable to keep this inflammable matter continually immersed under water.

As phosphorus exists in all vegetables, Dr. Darwin conjectures that it forms one of the articles of their food, and is absorbed entirely by their vessels, as often as it occurs in a state of solution ; though it may also be occasionally formed, and secreted, by plants. In his opinion, it essentially contributes to their growth, and imparts firmness to timber-trees.—See Phosphoric Acid.

In a medicinal view, phosphorus has a remarkable effect, on the human frame ; and, when administered with judgment and circumspection, forms a very powerful and valuable remedy. According to M. BarchEwitz, and other Continental writers, it has proved of essential service in paralytic, epileptic, melancholic, and maniacal attacks ; in every species of eruptive fevers; particularly in those where the eruption strikes in, and is accompanied with anxiety, convulsions and other nervous symptoms. He directs it to be given in doses of one grain, mixed with conserve of roses, or with any of the syrups.—Farther, a variety of cases have lately been published by M. Leroi, in France, who administered phosphorus internally with the greatest success, in consumptive diseases; in malignant fevers,where it effectually checked the progress of gangrene; and especially contri buted to the recovery of persons who had been reduced by intemperance. So potent a medicine, however, ought to be employed only with the utmost caution, and under the immediate superintend-ance of a competent judge.

Phosphoric Acid, is a peculiar acid, fixed in the fire, and composed of phosphorus, in combination with oxygen. It constitutes a material part of bone-ashes, from which it may be easily extracted by calcination, in the following manner : Take a large glass-jar, and dilute one pound of oil of vitriol with twelve pounds, or pints, of water ; then add gradually, under constant agitation of the mixture, one pound and a half of finely pulverized ashes of bones, calcined to whiteness. During this process, an effervescence takes place, and a Very pungent odour is disengaged. The vitriolic acid now forms gypsum, or sulphat of lime, by combining with the calcareous earth of the ashes ; and the phosphoric acid, thus separated, unites with the water.—We have purposely inserted this experiment; as we have reason to believe that the phosphoric acid, when largely diluted (for instance, in the proportion of one or two drams of the acid to every gallon of water) will prove highly fertilizing to the vegetable mould employed by gardeners. And, though we cannot sufficiently corroborate such conjecture from our own experience, yet there appears to be ample ground to recommend farther trials to be made with this active and powerful agent. We have already remarked, that it exists throughout the vegetable kingdom, and is supposed (by one of our most profound inquirers into the arcana of Nature) to have a considerable share in the process of vegetation. It has also been discovered in the mineral kingdom; tor instance, in the apatite, or phosphat of lime ; and in the green lead-spar found at Zschopau, in Saxony.-. This acid produces similar effects in the animal economy with the solid phosphorus ; and, when used as an ingredient in lemonade, M. Le-Roi informs us, that it has proved of eminent service in the disorders-above mentioned.