found possessed of phosphorescence. In genera scolopendra and nereis five or six ze luminous, which were all the species obed by Dr. M'Culloch. The other known era in which luminous species were observed e phalangium, monoculus, oniscus, iulus, ticella, cercaria, vibrio, volvox. To these Dr. Culloch adds, among the fishes, a new species leptocephalus. The remaining luminous imals consisted of new genera, or at least of imals which could not be referred to any as t to be found in authors. Dr. M'Culloch ems to think that the ling and other fish which habit the submarine valleys, at depths to which e light of day cannot penetrate, must perceive Ieir food, and pursue their avocations, by the Tosphorescence of their prey, or of the animals hich abound in the sea, or by phosphorescence icited from their own bodies. Dr. M'Culloch's bservations were generally made in harbours, ut never at a distance exceeding eight or ten iles from land. See the Journal of Science, Literature, &c., vol. xi. p. 248.

ions :

On the phosphorescence of the lampiris noctiluca nd splendidula. In a curious paper on the phoshorescence of the lampyris noctiluca and splenidula, published in the Bibliotheque Universelle or May 1821, p. 52, M. Macaire has drawn the Following conclusions from numerous observa1. A certain degree of heat is necessary o the voluntary phosphorescence of these aninals. 2. Their phosphorescence is excited by a degree of heat superior to the first, and is irrecoverably destroyed by a higher temperature. 3. All bodies capable of coagulating albumen take away from phosphorising matter its power of phosphorescence. 4. The phosphorescence cannot take place but in a gas which contains oxygen. 5. It is excited by the galvanic pile, but no effect is produced upon it by electricity. 6. The phosphorescent matter is composed principally of albumen. But see our article LIGHT.

PHOSPHORIC ACID. Bones of beef, mutton, or veal, being calcined to whiteness in an open fire, lose almost half of their weight. These must be pounded, and sifted; or the trouble may be spared by buying the powder that is sold to make cupels for the assayers, and is, in fact, the powder of burned bones ready sifted. To three pounds of the powder there may be added about two pounds of concentrated sulphuric acid. Four or five pounds of water must be also added to assist the action of the acid. The whole may be then left on a gentle sand heat for two or three days, taking care to supply the loss of water which happens by evaporation. A large quantity of water must then be added, the whole strained through a sieve, and the residual matter, which is sulphate of lime, must be edulcorated by repeated affusions of hot water, till it passes tasteless. The waters contain phosphoric acid with a little lime; and by evaporation, first in glazed earthen, and then in glass vessels, or rather in vessels of platina or silver (for the hot acid acts upon glass) afford the impure acid in a concentrated state, which, by the force of a strong heat in a crucible, may be made to acquire the form of a transparent consistent glass, though, indeed, it is usually of a milky opaque appearance. For

making phosphorus, it is not necessary to evaporate the water further than to bring it to the consistence of a syrup; and the small portion of lime it contains is not an impediment worth the trouble of removing, as it affects the produce very little. But, when the acid is required in a purer state, it is proper to add a quantity of carbonate of ammonia, which, by double elective attraction, precipitates the lime that was held in solution by the phosphoric acid. The fluid, being then evaporated, affords a crystallised ammoniacal salt, which may be melted in a silver vessel, as the acid acts upon glass or earthen vessels. The ammonia is driven off by the heat, and the acid acquires the form of a compact glass as transparent as rock-crystal, acid to the taste, soluble in water, and deliquescent in the air. This acid is commonly pure, but nevertheless may contain a small quantity of soda, originally existing in the bones, and not capable of being taken away by this process, ingenious as it is. The only unequivocal method of obtaining a pure acid appears to consist in first converting it into phosphorus by distillation of the materials with charcoal, and then converting this again into acid by rapid combustion, at a high temperature, either in oxygen or atmospheric air, or some other equivalent process.

Phosphorus may also be converted into the acid state by treating it with nitric acid. In this operation, a tubulated retort, with a ground stopper, must be half filled with nitric acid, and a gentle heat applied. A small piece of phosphorus, being then introduced through the tube, will be dissolved with effervescence, produced by the escape of a large quantity of nitric oxide. The addition of phosphorus must be continued until the last piece remains undissolved. The fire being then raised, to drive over the remainder of the nitric acid, the phosphoric acid will be found in the retort, partly in the concrete and partly in the liquid form. When phosphorus is burned by a strong heat, sufficient to cause it to flame rapidly, it is almost perfectly converted into dry acid, some of which is thrown up by the force of the combustion, and the rest remains upon the supporter.

This substance has also been acidified by the direct application of oxygen gas passed through hot water, in which the phosphorus was liquefied or fused.

The general characters of phosphoric acid are-1. It is soluble in water in all proportions, producing a specific gravity which increases as the quantity of acid is greater, but does not exceed 2.687, which is that of the glacial acid. 2. It produces heat when mixed with water, though not very considerable. 3. It has no smell when pure, and its taste is sour but not corrosive. 4. When perfectly dry, it sublimes in close vessels: but loses this property by the addition of water; in which circumstance it greatly differs from the boracic acid, which is fixed when dry, but rises by the help of water. 5. When considerably diluted with water, and evaporated, the aqueous vapor carries up a small portion of the acid. 6. With charcoal or inflammable matter, in a strong heat, it loses its oxygen, and becomes converted into phosphorus.

Phosphoric acid is difficult of crystallising. Though the phosphoric acid is scarcely corrosive, yet, when concentrated, it acts upon oils, which it discolors and at length blackens, producing heat, and a strong smell like that of ether and oil of turpentine; but does not form a true acid soap. It has most effect on essential oils, less on drying oils, and least of all on fat oils. From the syntheses of the phosphates of soda, barytes, and lead, Berzelius deduces the prime equivalent of phosphoric acid to be 4.5. But the experiments of Berzelius on the synthesis of the acid itself show it to be a compound of about 100 phosphorus + 133 oxygen. Lavoisier's synthesis gave 2 oxygen +1:33 phosphorus. So did that of Sir. H. Davy by rapid combustion in oxygen gas, as published in the Philosophical Transactions for 1812. M. Dulong in an elaborate paper published in the third volume of the Memoires D'Arceuil, gives, as the result of diversified experiments, nearly the proportions of 100 phosphorus to 123 oxygen; or of 5 oxygen + 4 phosphorus 9 for the acid equivalent.

Sir H. Davy, with his well known sagacity, invented a new method of research, to elude the former sources of error. He burned the vapor of phosphorus as it issues from a small tube, contained in a retort filled with oxygen gas. By adopting this process, he determined the composition of phosphoric acid to be 100 phosphorus +134.5 oxygen; whence its equivalent comes out 3.500. Phosphorous acid he then shows to consist of 1 oxygen + 1:500 phosphorus = 2.500.

M. Dumas in an elaborate memoir on Phosphureted Hydrogen (Ann. de Chim. et de Phys. xxxi.) endeavours to show that phosphoric acid consists of 1 atom of phosphorus, 40+ 5 atoms of oxygen, 59; while phosphorous acid consists of 1 atom of phosphorus 4+ 3 atoms of oxygen, 3 = 7. See PHOSPHURETED HYDROGEN.

By the above atomic weights 1.5 phosphorus combines with 1.125 oxygen (instead of 1) to constitute phosphorous acid; and with 1875 oxygen to constitute phosphoric acid. If phosphoric acid be made 9, then in the phosphates of soda, barytes, and lead, we must admit 2 atoms of base; thus giving them the characters of subsalts, which that of soda manifestly possesses. PHOSPHORITE, in mineralogy, a subspecies of apatite. Common phosphorite is of a yellowish-white color, when rubbed in an iron mortar, or thrown on red hot coals. It emits a green-colored phosphoric light. It is found in Estremadura in Spain. Earthy phosphorite is of a grayish-white color, and consists of dull dusty particles, which phosphoresce on glowing coals. It is found in Hungary.

the water, will concrete into the solid phosphorus.

M. Javal finds that the subphosphate of la obtained by digesting five parts of calcined, powder with two parts of sulphuric an better adapted to yield phosphorus by p with charcoal in a retort than pure pho acid. The latter sublimes in a great me undecomposed. Ann. de Chim. et de Phy June, 1820.

It must be purified by straining it thro piece of chamois leather, under warm waE is yellow and semi-transparent. It is as st wax, but fully more cohesive and ductile. specific gravity is 1.77. It melts at 90° F heit, and boils at 550°. In the atmospher common temperatures, it emits a white sa which, in the dark, appears luminous. smoke is acidulous, and results from the oxygenation of the phosphorus. In air pera dry, however, phosphorus does not smele cause the acid which is formed is solderi closely incasing the combustible, screens it i the atmospherical oxygen.

When phosphorus is heated in the air to r 148° it takes fire, and burns with a splet white light, and a copious dense smoke. li combustion take place within a large glas ceiver, the smoke becomes condensed snowy looking particles, which fall in a s sive shower, coating the bottom plate spongy white efflorescence of phosphoric This acid snow soon liquefies by the abso of aqueous vapor from the air. When inflamed in oxygen the light and heat are ~ comparably more intense; the former dan the eye, and the latter cracking the glass rese Solid phosphoric acid results; consisting 4 phosphorus + 5.0 oxygen, or 1 atom phosphorus + 5 of oxygen.

Phosphorus, heated in highly rarefied air, form three products: one is phosphoric acid; a volatile white powder; and the third a solid of comparative fixity, requiring a above that of boiling water for its fusion. I volatile substance is soluble in water, imparti acid properties to it. It seems to be phosph acid. The red substance is probably an of phosphorus, since for its conversion phosphoric acid it requires less oxygen phosphorus does. See PHOSPHORIC, PHOSP ROUS, and HYDROPHOSPHOROUS ACIDS. Phosphorous acid is composed of 1 a phosphorus +3 oxygen = 4 + 3 = 7.

than

take

orus and chlorine, first described as a pecu· body by Sir H. Davy in 1810; and various lytical and synthetical experiments which he de with it prove that it consists of about 1 osphorus, and 68 chlorine in weight. The uivalent ratio of 1 prime of the first + 6 of e second constituent, gives 4 to 27, or 1 to 75. It is the bichloride of phosphorus. This se shows the necessity in chemistry of abiding experiment; for Sir H. Davy's untrimmed sult, which had been called in question or ghtly esteemed by the ultra-atomists, who itched on 1-5 for the prime equivalent of phoshorus, is now seen to accord perfectly with the orrected prime equivalent of Dumas.

Its properties are very peculiar. It is snowhite, extremely volatile, rising in a gaseous orm at a temperature much below that of boilng water. Under pneumatic pressure it may be fused, and then it crystallises in transparent prisms. It acts violently on water, decomposing t, whence result phosphoric and muriatic acids; he former from the combination of the phoshorus with the oxygen, and the latter from that of the chlorine with the hydrogen of the water. It produces flame when exposed to a lighted aper. If it be transmitted through an ignited glass tube along with oxygen, it is decomposed, and phosphoric acid and chlorine are obtained. The superior fixity of the acid above the chloride seems to give that ascendancy of attraction to the oxygen here, which the chlorine possesses in most other cases. Dry litmus paper exposed to its vapor in a vessel exhausted of air is reddened. When introduced into a vessel containing ammonia, a combination takes place, accompanied with much heat, and there results a compound, insoluble in water, undecomposable by acid or alkaline solutions, and possessing characters analogous to earths.

The protochloride of phosphorus was first obtained in a pure state by Sir H. Davy, in the year 1809. If phosphorus be sublimed through corrosive sublimate, in powder in a glass tube, a limpid fluid comes over as clear as water, and having a specific gravity of 1:45. It emits acid fumes when exposed to the air, by decomposing the aqueous vapor. If paper imbued with it be exposed to the air, it becomes acid without inflammation. It does not redden dry litmus paper plunged into it. Its vapor burns in the flame of a candle. When mixed with water, and heated, muriatic acid flies off, and phosphorous acid remains. See PHOSPHOROUS ACID. If it be introduced into a vessel containing chlorine, it is converted into the bichloride; and, if made to act upon ammonia, phosphorus is produced, and the same earthy-like compound results as that formed by the bichloride and ammonia.

When phosphorus is gently heated in the protochloride, a part of it dissolves, and the fluid, on exposure to air, gives off acid fumes, from its action on atmospheric inoisture, while a thin film of phosphorus is left behind, which usually inflames by the heat generated from the decomposition of the vapor. The first compound of this kind was obtained by M. M. Gay Lussac and Thenard, by distilling phosphorus and calomel together, in 1808; and they ima

gined it to be a peculiar combination of phosphorus, oxygen, and muriatic acid. No experiments have yet ascertained the quantity of phosphorus which the protochloride will dissolve. Probably, says Sir H. Davy, a definite combination may be obtained, in which the proportion of chlorine will correspond to the proportion of oxygen in the oxide of phosphorus.

The compounds of iodine and phosphorus have been examined by Sir H. Davy and M. Gay Lussac. Phosphorus unites to iodine with the disengagement of heat, but no light. One part of phosphorus and eight of iodine form a compound of a red orange-brown color, fusible at about 212°, and volatile at a higher temperature. When brought in contact with water, phosphureted hydrogen gas is disengaged, flocks of phosphorus are precipitated, and the water, which is colorless, contains in solution phosphorous and hydriodic acids. One part of phosphorus and sixteen of iodine produce a crystalline matter of a grayish-black color, fusible at 84°. The hydriodic acid produced by bringing it in contact with water is colorless, and no phosphureted hydrogen gas is disengaged. One part of phosphorus and twenty-four of iodine produce a black substance partially fusible at 115°. Water dissolves it, producing a strong heat, and the solution has a very deep brown color, which is not removed by keeping it for some time in a gentle heat. With 1 phosphorus and 4 iodine, two compounds, very different from each other, are obtained. One of them has the same color as that formed of 1 phosphorus + 8 iodine, and seems to be the same with it. It melts at 217.5°, and, when dissolved in water, yields colorless hydriodic acid, phosphureted hydrogen, and phosphorus ; which last precipitates in orange-yellow flocks. The other compound is a reddish-brown, does not melt at 212°, nor at a considerably higher temperature. Water has no sensible action on it. Potassa dissolves it with the disengagement of phosphureted hydrogen gas; and, when aqueous chlorine is poured into the solution, it shows only traces of iodine. When heated in the open air, it takes fire and burns like phosphorus, emitting white vapors, without any iodine. When these vapors were condensed in a glass jar by M. Gay Lussac he could perceive no iodine among them. This red substance is always obtained when the phosphorus is in the proportion of 1 to 4 of iodine. M. Gay Lussac is inclined to consider it as identical with the red matter which phosphorus so often furnishes, and which is at present considered as an oxide. In whatever proportions the iodide of phosphorus has been made, it exhales acid vapors, as soon as it is moistened, owing to the hydriodic acid formed by the decomposition of the water. Such is the account of the iodide of phosphorus given by M. Gay Lussac. The combining ratios are somewhat uncertain.

PHOSPHOROUS ACID was discovered in 1812

by Sir H. Davy. When phosphorus and corrosive sublimate act on each other, at an elevated temperature, a liquid called protochloride of phosphorus is formed. Water, added to this, re

solves it into muriatic and phosphorous acids. A moderate heat suffices to expel the former, and the latter remains, associated with water. It has a very sour taste, reddens vegetable blues, and neutralises bases. When heated strongly, in open vessels, it inflames. Phosphureted hydrogen flies off, and phosphoric acid remains. Ten parts of it heated in close vessels give off onehalf of a phosphureted hydrogen, and leave 8 of phosphoric acid. Hence the liquid acid consists of 80-7 acid + 19.3 water. Its prime equivalent is either 2.5 or 7. See PHOSPHURETED HYDROGEN.

A hypophosphorous acid was lately discovered by Dulong. Pour water on the phosphuret of barytes, and wait till all the phosphureted hydrogen be disengaged. Add cautiously to the filtered liquid dilute sulphuric acid, till the barytes be all precipitated in the state of sulphate. The supernatant liquid is hypophosphorous acid, which should be passed through a filter. This liquid may be concentrated by evaporation, till it become viscid. It has a very sour taste, reddens vegetable blues, aud does not crystallise. It is probably composed of 2 primes of phosphorus =3+1 of oxygen. Dulong's analysis approaches to this proportion. He assigns, but from rather precarious data, 100 phosphorus to 37-44 oxygen. The hypophosphites have the remarkable property of being all soluble in water; while many of the phosphates and phosphites are insoluble.

Thenard succeeded in oxygenising phosphoric acid by the method described under NITRIC and MURIATIC ACIDS.

With regard to the phosphates and phosphites, we have many discrepancies in our latest publications. Sir H. Davy says, in his last memoir on some of the combinations of phosphorus, that new researches are required to explain the anomalies presented by the phosphates.

Phosphoric acid, united with barytes, produces an insoluble salt, in the form of a heavy white powder, fusible at a high temperature into a gray enamel. The best mode of preparing it is by adding an alkaline phosphate to the nitrate or muriate of barytes.

By mixing phosphate of ammonia with nitrate of barytes, Berzelius found that 68-2 parts of barytes, and 318 of phosphorus, composed 100 of the phosphate. Hence it is a subphosphate,

and consists of,

The phosphate of strontian differs from preceding in being soluble in an excess dij acid.

Phosphate of lime is very abundant u native state. See APATITE. It likewis tutes the chief part of the bones of all a

Phosphate of lime is very difficult to fi in a glass-house furnace it softens, and an the semitransparency and grain of porcela is insoluble in water; but, when well cy forms a kind of paste with it, as in cupels. Besides this use of it, it is en for polishing gems and metals, for abs grease from cloth, linen, or paper, and fr paring phosphorus. In medicine it has in strongly recommended against the rickets by Bonhomme of Avignon, either alone or com with phosphate of soda. The burnt ba of the shops is a phosphate of lime.

An acidulous phosphate of lime is fou human urine, and may be crystallised in silky filaments, or shining scales, which together into something like the consisten honey, and have a perceptibly acid tast may be prepared by partially decomposing calcareous phosphate of bones by the sulpte nitric, or muriatic acid, or by dissolving phosphate in phosphoric acid. It is so water, and crystallisable. Exposed to the of heat, it softens, liquefies, swells up, bee dry, and may be fused into a transparent which is insipid, insoluble, and unaltera the air.

In these characters it differs from glacial acid of phosphorus. It is part composable by charcoal, so as to afford por phorus.

By pouring phosphate of soda into muria lime, Berzelius obtained a phosphate of consisting of acid 100, lime 84:53. The proportions are,

Phosphuric acid = 9=100

Lime 3.5 x 27 = 78 nearly. The phosphate of potassa is very deliques and not crystallisable, but condensing intoak of jelly. Like the preceding species, it first dergoes the aqueous fusion, swells, dries may be fused into a glass; but this glass des quesces. It has a sweetish saline taste. T phosphate of soda is now commonly prep by adding to the acidulous phosphate of much carbonate of soda in solution as will f

saturate the acid. The carbonate of lime w precipitates, being separated by filtration, liquid is duly evaporated so as to crystallise is phosphate of soda; but, if there be not a sh excess of alkali, the crystals will not be late and regular. The crystals are rhomboidal prisa of different shapes; efflorescent; soluble in the of cold and one and a half of hot wat parts

b

They are capable of being fused into an ope white glass, which may be again dissolved a crystallised. It may be converted in an airlous phosphate by an addition of acid, or either of the strong acids, which partially, not wholly, decompose it. As its taste is simply saline, without any thing disagreeable, it is much used as a purgative, chiefly in broth, in which is not distinguishable from common salt. For this elegant addition to our pharmaceutical pre

D

hich presents a good accordance with the expemental results of the accurate Berzelius. The phosphate of ammonia crystallises in risms with four regular sides, terminating in yramids, and sometimes in bundles of small eedles. Its taste is cool, saline, pungent, and rinous. On the fire it comports itself like the receding species, except that the whole of its ase may be driven off by a continuance of the eat, leaving only the acid behind. It is but little nore soluble in hot water than in cold, which akes up a fourth of its weight. It is pretty bundant in human urine. It is an excellent ux both for assays and the blow-pipe, and in the abrication of colored glass and artificial gems. Phosphate of magnesia crystallises in irreular hexahedral prisms, obliquely truncated; out is commonly pulverulent, as it effloresces very quickly. It requires fifty parts of water to lissolve it. Its taste is cool and sweetish. This salt too is found in urine. Fourcroy and Vauquelin have discovered it likewise in small quantity in the bones of various animals, though not in those of man. The best way of preparing it is by mixing equal parts of the solutions of phosphate of soda and sulphate of magnesia, and leaving them some time at rest, when the phosphate of magnesia will crystallise, and leave the sulphate of soda dissolved.

An ammoniaco-magnesian phosphate has been discovered in an intestinal calculus of a horse by Fourcroy, and since by Bartholdi, and likewise by the former in some human urinary calculi. See CALCULUS. Notwithstanding the solubility of the phosphate of ammonia, this triple salt is far less soluble than the phosphate of magIt is partially decomposable into phosphorus by charcoal, in consequence of its ammonia.

nesia.

The phosphate of glucine has been examined by Vauquelin, who informs us that it is a white powder, or mucilaginous mass, without any perceptible taste; fusible, but not decomposable by heat; unalterable in the air, and insoluble unless in an excess of its acid.

It has been observed that the phosphoric acid, aided by heat, acts upon silex; and we may add, that it enters into many artificial gems in the state of a siliceous phosphate. See SALT.

PHOSPHORUS (of Baldwin), a name for ignited

muriate of lime.

PHOSPHORUS (of Canton). Oyster shells calcined with sulphur.

255

PHOSPHORUS (of Bologna). See LIGHT. Sulphate of barytes.

PHOSPHURET. A compound of phospчorus with a combustible or metallic oxide.

PHOSPHURETED HYDROGEN. Of this compound there are two varieties; one of which may be called perphosphureted hydrogen; another protophosphureted hydrogen.

1. Perphosphureted hydrogen. Into a small retort filled with milk of lime, or potissa water, let some fragments of phosphorus be introduced, and let the heat of an Argand flame be applied to the bottom of the retort, while its beak is immersed in the water of a pneumatic trough. Bubbles of gas will come over, which explode spontaneously with contact of air. It may also be procured by the action of dilute muriatic acid on phosphuret of lime. In order to obtain the gas pure, however, we must receive it over mercury. Its smell is very disagreeable. Its specific gravity is 0.9022. 100 cubic inches weigh 27-5 grains. In oxygen it inflames with a brilliant white light. In common air, when the gaseous bubble bursts the film of water and explodes, there rises up a ring of white smoke, luminous in the dark. Water absorbs about one-fortieth of its bulk of this gas, and acquires a yellow color, a bitter taste, and the characteristic smell of the gas. When brought in contact with chlorine it detonates with a brilliant green light; but the products have never been particularly examined. By transmitting a series of electric explosions through phosphureted hydrogen, the phosphorus is precipitated, and hydrogen of the original gaseous volume remains. Hence the composition of the gas may be deduced from a comparison of its specific gravity with that of hydrogen.

Phos. difference of weight, 0-8328 Thus we perceive that this compound consists of 0.8328 phosphorus + 0.0694 hydrogen; or 12+ 1; or 15+0-125 1.625, which is the weight of the sum of the primes, commonly called the weight of its atom. The gas may be likewise conveniently analysed by nitrous gas, nitrous oxide, or oxygen. The preceding densities and proportions are those currently given by British writers, and are probably incorrect. See these numbers corrected by M. Dumas further on, and also in the general TABLE of GASES.

2. Protophosphureted hydrogen. It was discovered by Sir H. Davy in 1812. When the crystalline hydrate of phosphorous acid is heated in a retort out of the contact of air, solid phosphoric acid is formed, and a large quantity of subphosphureted hydrogen is evolved. Its smell is fetid, but not so disagreeably so as that of the preceding gas. It does not spontaneously explode like it with oxygen; but at a temperature of 300° a violent detonation takes place. In chlorine it explodes with a white flame. Water absorbs one-eighth of its volume of this gas. When potassium is heated in it its volume is doubled, and the resulting gas is pure hydrogen. When sulphur is sublimed in one volume of it