Chapter XL: Part 2 (1)

Oxalic acid.
Chloroform.
Belladonna and its preparations.
Essential oil of almonds, unless deprived of its prussic acid.
Opium and all preparations of opium or of poppies.

By virtue and in exercise of the powers vested in the council of the Pharmaceutical Society of Great Britain, the said council do hereby resolve and declare that each of the following articles, viz.——

Preparations of prussic acid,
Preparations of cyanide of potassium and of all metallic cyanides,
Preparations of strychnine,
Preparations of atropine,
Preparations of corrosive sublimate,
Preparations of morphine,
Red oxide of mercury (commonly known as red precipitate of mercury),
Ammoniated mercury (commonly known as white precipitate of mercury),
Every compound containing any poison within the meaning of ‘The Pharmacy
Act, 1868,’ when prepared or sold for the destruction of vermin,
The tincture and all vesicating liquid preparations of cantharides,

——ought to be deemed a poison within the meaning of the ‘Pharmacy Act, 1868,’ and also that of the same each of the following articles, viz.——

Preparations of prussic acid,
Preparations of cyanide of potassium and of all metallic cyanides,
Preparations of strychnine,
Preparations of atropine,

——ought to be deemed a poison in the first part of the schedule (A) to the said ‘Pharmacy Act, 1868,’

And notice is hereby also given, that the said Society have submitted the said resolution for the approval of the Lords of Her Majesty’s Council, and that such approval has been given.

By order,
ELIAS BREMRIDGE,
_Secretary and Registrar of the Pharmaceutical
Society of Great Britain._

And whereas the council of the Pharmaceutical Society of Great Britain did, on the 17th day of November, 1877, resolve and declare in the words following:——

“That by virtue and in exercise of the powers vested in the council of the Pharmaceutical Society of Great Britain, the said council does hereby resolve and declare that _Chloral Hydrate and its preparations_ ought to be deemed poisons within the meaning of the ‘Pharmacy Act, 1868,’ and ought to be deemed poisons in the second part of the schedule (A) of the said ‘Pharmacy Act, 1868.’”

And whereas the said Society have submitted the said resolution for the approval of the Privy Council, and the Lords of the Privy Council are of opinion that the said resolution should be approved.

Now, therefore, their Lordships are hereby pleased to signify their approval of the said resolution.

C. L. PEEL.

Tardieu states that of late years the criminal administration of phosphorus has increased considerably in France. For example, from 1851 to 1872, in 793 cases of poisoning, 287 or 36·2 per cent. were due to arsenic, and 267 or 31·1 per cent. to phosphorus; whilst in the years 1872 and 1874, in 141 criminal poisonings by arsenic and phosphorus, only 74 were due to arsenic. The explanation of these facts may reasonably be ascribed to the much greater facility with which phosphorus, in the form of matches or vermin pastes, can be procured than arsenic.

=PHE′NOL.= C_{6}H_{6}O. See CARBOLIC ACID.

=PHE′NYL.= C_{6}H_{5}. The hypothetical compound radical of the phenyl-series. Carbolic acid is said to be its hydrate.

=PHENYL′AMINE.= C_{6}H_{5}H_{2}N. Aniline is sometimes so named on account of its relation to the phenyl series.

=PHIALS.= The ordinary green moulded phials used by the pharmaceutist are made of a glass obtained from common river sand and soapboilers’ waste. In the manufacture of the glass for the white phials purer materials (and these as free from iron and alumina as possible) are used. Decolourising agents are also employed. The following is given as the composition of a white glass for apothecaries’ phials in ‘Chemistry: Theoretical, Practical, and Analytical,’[94]

[Footnote 94: Mackenzie and Co.]

100 lbs. white sand.
30-26 ” potash, impure.
17 ” lime.
110-120 ” ashes.
·25 to ·5 lbs. binoxide of manganese-cullet.

=Phials, Bologna.= Small flasks or phials of unannealed glass, which fly to pieces when their surface is scratched by a hard body. Thus, if a small piece of flint be dropped into them they are shivered; whereas if a bullet be used they remain uninjured.

=PHILO′NIUM.= The ancient name of an aromatic opiate, reputed to possess many virtues, invented by Philo. See CONFECTION OF OPIUM.

=PHILOS′OPHER’S STONE.= _Syn._ LAPIS PHILOSOPHORUM, L. A wonderful substance, the discovery of which formed the day dreams of the alchemists. It was supposed to be capable of converting all the baser metals into gold, and of curing all diseases. Some of the alchemists appear to have laboured under the delusion that they had actually discovered it. The last of these enthusiasts was the talented and unfortunate Dr Price, of Guildford. Speaking of the age of alchemy, Liebig says:——“The idea of the transmutability of metals stood in the most perfect harmony with all the observations and all the knowledge of that age, and in contradiction to none of these. In the first stage of the development of science, the alchemists could not possibly have any other notions of the nature of metals than those which they actually held.... We hear it said that the idea of the philosopher’s stone was an error; but all our views have been developed from errors, and that which today we regard as truth in chemistry may, perhaps, before to-morrow, be regarded as a fallacy.”

=PHILOSOPH′IC CANDLE.= An inflamed jet of hydrogen gas.

=PHILOSOPHIC WOOL.= Flowers of zinc.

=PHIL′TRE.= _Syn._ PHILTRUM, L. A charm or potion to excite love. The ancients had great faith in such remedies. Nothing certain is now known respecting their composition; but there is sufficient evidence that recourse was frequently had to them by the ancients, and that “their operation was so violent that many persons lost their lives and their reason by their means.” The Thessalian philtres were those most celebrated. (Juv., vi, 610, &c.) At the present day the administration of preparations of the kind is interdicted by law.

=PHLORE′TIN.= C_{15}H_{14}O_{5}. A crystallisable, sweet substance, formed along with grape sugar, when phloridzin is acted on by dilute acids.

=PHLORID′ZIN.= C_{21}H_{24}O_{10}. _Syn._ PHLORIZINE; PHLORIDZINUM, L. Prep. By acting on the fresh root-bark of the apple, pear, or plum tree, with boiling rectified spirit; the spirit is distilled off, and the phloridzin crystallises out of the residual liquor as it cools.

_Prop., &c._ Fine, colourless, silky needles, freely soluble in rectified spirit and in hot water, but requiring 1000 parts of cold water for its solution; its taste is bitter and astringent. When its solution is boiled with a little dilute sulphuric acid or hydrochloric acid, it is changed into grape sugar and phloretin.

Phloridzin bears a great likeness to salicin. It is said to be a powerful febrifuge.——_Dose_, 3 to 15 gr.

=PHOCE′NIC ACID.= See DELPHINIC ACID.

=PHŒNIC′INE.= See INDIGO PURPLE.

=PHO′NOGRAPH.= Some years back Prof. Faber, of Vienna, constructed and exhibited in the chief cities of Europe ‘a talking machine,’ which was able to articulate simple words and sentences with considerable distinctness. The complex mechanism by which this was effected was contrived upon the principles of the human organs of speech, as the machine possessed an india-rubber tongue and lips, and an artificial larynx, made out of a thin vibrating tube of ivory. Faber’s automaton, although of much greater scientific interest than the automatic flute and flageolet players of Vancanson, the trumpeter of Droz, and similar exhibitions of curious workmanship, was, like these, only a mechanical curiosity, without any promise of a useful application.

Entirely distinct from Faber’s machine, not only structurally and in the method by which it produces its effects, but also in the end designed for it by its inventor being an essentially practical one, is the ‘speaking machine or phonograph’ of Mr Edison.

The first impression that will occur to those who having heard Mr Edison’s instrument speak have subsequently made themselves acquainted with its construction, will probably be one of surprise that an effect so apparently startling as that which it has been able to produce should be accomplished by means so simple.

B is a brass cylinder, through whose centre passes a metal shaft, the arms of which rest on upright supports, one of which is shown in the engraving. The arm of the shaft, obscured from view, corresponding in length with the part of it which is visible, is screw-turned, and it works in a nut bored out of the support. Attached to the screw-end of the shaft or axle is a crank C, by turning which a double movement, viz. a rotatory and a horizontal one, may be simultaneously imparted to the cylinder. Round the surface of the cylinder is cut a spiral groove corresponding in dimensions with the threads of the screw part of the shaft. Covering the whole of the cylinder is a sheet of tin-foil, which is secured to its edges by means of shell-lac varnish. In front of the cylinder, resting on a proper support, is a mouth-piece, A, at the bottom of which (the end nearest the cylinder) is a very thin plate or diaphragm of metal, and to this diaphragm is attached a round steel point, which when not in use does not touch the foil. Previously to using the apparatus this steel point has to be accurately adjusted opposite to that part of the foil lying over the spiral groove. If now the lips be applied to the mouth-piece, and any sentence be spoken, the crank being at the same time turned, the vibrations imparted to the metal plate by the voice will cause the steel point to come into contact with that part of the foil overlying the groove in the cylinder, and to make on the foil a number of indentations, as it revolves, and is carried forward laterally before the mouth-piece. Furthermore these indentations will be found to vary in depth and sectional outline according to the nature of the vibrations which have produced them; and as experiment proves, are the specific and infallible caligraphy of those vibrations.

“It might be said that at this point the machine has already become a complete phonograph or sound writer, but it yet remains to translate the remarks made. Now, there is no doubt that by practice and the aid of a magnifier it would be possible to read phonetically Mr Edison’s record of dots and dashes,[95] but he saves us that trouble by literally making it read itself. The distinction is the same, as if, instead of perusing a book ourselves, we drop it into a machine, set the latter in motion, and behold! the voice of the author is heard repeating his own composition. The reading mechanism is nothing but another diaphragm, held in the tube D, on the opposite side of the machine, and a point of metal, which is held against the tin-foil on the cylinder by a delicate spring.

[Footnote 95: According to the ‘Polytechnic Review,’ Mr Edison does not appear to have yet solved the problem of reading the phonograph record by sight. He states that although a specific form exists for each articulated sound, the chief difficulties arise from the varying indentations or marks caused by the same sound. Amongst the circumstances giving rise to these results are: the same sound uttered by different people, the manner in which it is spoken, the distance of the mouth from the instrument, the force with which it is spoken, or the speed with which the barrel is rotated.]

“It makes no difference as to the vibrations produced, whether a nail moves over a file or a file moves over a nail, and in the present instance it is the foil or indented foil-strip which moves, and the metal point is caused to vibrate as it is affected by the passage of the indentations. The vibrations, however, of this point must be precisely the same as those of the other points which made the indentations, and these vibrations transmitted to a second membrane, must cause the latter to vibrate similar to the first membrane, and the result is a synthesis of the sounds, which in the beginning we saw, as it were, analysed.”[96]

[Footnote 96: ‘Scientific American,’ December, 1877.]

In some of the later instruments, that section of the apparatus shown at D is dispensed with, and the reproduction of the spoken words or sentences is effected by bringing the cylinder back to its original starting point, opposite to the little steel projection attached to the metal disc at the end of the mouth-piece A. The steel point is then brought by means of a screw into contact with the foil, and as the cylinder moves onward in its former track, the metal point retraces the indentations on the foil from beginning to end, in doing which it communicates the vibrations it thus receives to the metal diaphragm in precisely the same manner, and with the same results as were shown with D. For the diaphragm, more particularly when employed as a resonator or reproducer of the words which have been spoken into the mouth-piece, other substances than metal have been tried, with, it is said, more satisfactory results. One of these is paper, the sounds given off by which are stated to be more distinct than those from iron.

Dr Clarence Holt, of Boston, in a communication to Mr W. H. Preece, writes that he has “constructed a diaphragm upon the principle of the membrane of the human drum of the ear, to be used as a reproducing disc.” Dr Holt continues “that his object was to employ a membrane which from its structure and shape would reproduce the lighter over-tones representing the quality of the voice, and at the same time cut off the sharper exaggerated over-tones embossed as such by the metal disc upon the tinfoil. He says the results of his experiments with such a membrane were very gratifying, and that the material of which it may be made should be either stout felted paper (to be varnished on the outer surface when used for speaking) or drum head moistened and pressed into a concave form before using.”[97]

[Footnote 97: Published in ‘Nature,’ February 4th, 1878.]

The crank (shown in the figure) by which the cylinder is turned is very frequently supplanted by an apparatus consisting of weights and wheels, or else by clockwork, whereby the cylinder is put in motion. The advantage of the working of these arrangements over that of the crank are, that instead of an inequality a regularity of movement of the cylinder is ensured, and it is thus made to advance at the same rate whilst the words are being reproduced as when they are being spoken.

One of the effects of this uniformity of the rotation of the cylinder under its two modes of action is to reproduce the exact pitch or tone of the voice of the speaker, although a departure from it would in no way affect the delivery of the exact words.

Accordingly, therefore, to the difference in the rate of movement of the cylinder during the reception and reproduction of speech, will be the divergence in tone between the original and the reproduced voice. If the cylinder were moved more quickly in redelivering the words the result would be that they would be in a higher, and, in the opposite case, in a lower key. Probably, as one writer has suggested, the curious effect might be produced of a child’s voice being converted into a man’s deep base, or _vice versâ_.

In view of the results of previous scientific discoveries, we should not be justified in refusing to admit the possibility, at any rate, of the realisation of some of the applications to which its inventor believes the phonograph will, in the course of time, be put.

It must be admitted that these predictions as to its ultimate capabilities are sufficiently wondrous. They are that——the phonograph will be able to record and reproduce at a future time any air sung to it, so that the vocal triumphs of some of our most accomplished singers may be preserved and resung after their death; that by its means may also be conserved and respoken, likewise after death, a speech delivered by a great statesman or orator; that a dying testator by breathing into it his last wishes may have these securely registered, to be expressed after his demise, if need be, in a court of justice; and that the contents of a book or novel may be read to us in the very accents of its author, long after he has passed away.

Although we have no testimony that anything like an approach to the above results has been obtained by this instrument, such statements as we possess of its action are not a little surprising.

“Mr Thomas Edison,” says the ‘Scientific American,’ describing this contrivance, “recently came into our office, placed a little machine on our desk, turned a crank, and the machine inquired as to our health, asked how we liked the phonograph, informed us that it was well, and bid us a cordial good night. These remarks were not only perfectly audible to ourselves, but to a dozen or more persons gathered round.”

At a meeting of the Physical Society of London, held on the 2nd of March, 1878, when the phonograph was exhibited, the sounds it gave out are said to have been remarkably distinct; and when “God Save the Queen” was sung as a duet through a double mouth-piece, the two voices could be clearly distinguished on the air being reproduced.

The writer was at the Royal institution in Albemarle Street a short time previous to the above date, and although sitting in the top gallery, heard it emit very distinctly the line “Come into the garden, Maud,” spoken by Professor Tyndall in compliment to the Laureate, who was present as well as various other vocal reproductions. The secondary sound, however, was less powerful than the original one. The difference between the two is aptly described by a writer in ‘Nature,’ as causing a feeling like that of looking upon a worn print and an early wood engraving.

“The main utility of the phonograph,” says Mr Edison, “being for the purpose of letter-writing, and other forms of dictation, the design is made, with a view to its utility for that purpose.

“The general principles of construction are a flat plate or disc, with spiral groove on the face, operated by clockwork underneath the plate; the grooves are cut very closely together, so as to give a great total length to each inch of surface——a close calculation gives as the capacity of each sheet of foil, upon which the record is had, in the neighbourhood of 40,000 words. The sheets being but 10 inches square, the cost is so trifling that but 100 words might be put upon a single sheet economically.

“The practical application of this form of phonograph for communications is very simple. A sheet of foil is placed in the phonograph, the clockwork set in motion, and the matter dictated in the mouth-piece, without other effort than when dictating to a stenographer. It is then removed, placed in a suitable form of envelope, and sent through the ordinary channels to the correspondent for whom designed. He, placing it upon his phonograph, starts his clockwork, and _listens_ to what his correspondent has to say. Inasmuch as it gives the tone of voice of his correspondent it is _identified_. As it may be filed away as other letters and at any subsequent time reproduced, it is a perfect _record_. As two sheets of foil have been indented with the same facility as a single sheet, ‘the writer’ may thus keep a _duplicate_ of his communication.

“The phonograph letters maybe dictated at home or in the office of a friend, the _presence_ of a stenographer _not being required_. The dictation may be as rapid as the thoughts can be formed, or the lips utter them. The recipient may listen to his letters being read at the rate of 150 to 200 words per minute, and at the same time busy himself about other matters. Interjections, explanations, emphasis, exclamations, &c., may be thrown into such letters _ad libitum_.

“The advantages of such an innovation upon the present slow, tedious, and costly methods are too numerous, and too readily suggest themselves, to warrant their enumeration; while there are no disadvantages which will not disappear coincident with the general introduction of the new method.”[98]

[Footnote 98: ‘North American Review,’ May, 1878.]

=PHOS′GENE GAS.= See CHLOROCARBONIC ACID.

=PHOS′PHATE.= _Syn._ PHOSPHAS, L. A salt of phosphoric acid. See PHOSPHORIC ACID and the respective metals.

=PHOS′PHIDE.= See PHOSPHURET.

=PHOS′PHITE.= _Syn._ PHOSPHIS, L. A salt of phosphorous acid. See PHOSPHOROUS ACID.

=PHOS′PHORUS.= P.

_Prep._ This is now only conducted on the large scale:——Bone-ash (in powder), 12 parts, and water 24 parts, are stirred together in a large tub until the mixture is reduced to a perfectly smooth ‘pap,’ oil of vitriol, 8 parts, is then added in a slender stream, active stirring being employed during the whole time, and afterwards until the combination appears complete; the next day the mass is thinned with cold water, and, if convenient, heated in a leaden pan or boiler until it has entirely lost its granular character; it is now transferred to one or a series of tall casks (according to the extent of the batch), and further diluted with a large quantity of water; after repose, the clear liquid is decanted, the sediment washed with water, and the ‘washings’ and ‘decanted liquor’ evaporated in a leaden or copper boiler until the white calcareous deposit (gypsum) becomes considerable; the whole is then allowed to cool, the clear portion decanted, and the sediment thoroughly drained on a filter; the liquid thus obtained is evaporated in an iron pot to the consistence of a thick syrup (say 4 parts), when dry charcoal (in powder), 1 part, is added, and the desiccation continued until the bottom of the pot becomes nearly red hot, after which it is covered over and allowed to cool; the dry mixture, when cold, is put into one or more earthen retorts well covered with ‘luting’ and properly dried, and heat is applied (sideways rather than at the bottom) by means of a good air-furnace; after a short time the beak of the retort is connected with a copper tube, the other end of which is made to dip about one fourth of an inch beneath the surface of some lukewarm water placed in a trough or wide-mouthed bottle.

The distilled product is purified by squeezing it through chamois leather under warm water, and is then moulded for sale by melting it under water heated to about 145° Fahr., and sucking it up to any desired height in slightly tapering, but perfectly straight, glass tubes, previously warmed and wetted. The bottom of the tube being now closed with the finger, it is withdrawn, and transferred to a pan of cold water to congeal the phosphorus, which will then commonly fall out, or may be easily expelled by pressure with a piece of wire.

_Prop. &c._ Phosphorus in its normal condition is a pale yellow, semi-transparent, and highly combustible solid; soft and flexible at common temperatures; it becomes waxy at about 75° Fahr.; melts at about 111°, and boils at 550° Fahr.; it takes fire in the air at 165°, and oxidates at all temperatures above 32°. Exposed to the air below 60°, its surface is slowly converted into phosphorus acid. It is apparently insoluble in water, but it conveys its peculiar flavour and odour to that fluid when agitated with it; it is slightly soluble in ether, naphtha, and the fixed and volatile oils, and more freely so in bisulphide of carbon. It unites with oxygen, forming oxides, and with oxygen and hydrogen, forming acids, and with the metals, forming phosphides.

Phosphorus is remarkable for assuming several allotropic forms. In one of these forms (amorphous phosphorus) its properties are so altered that they might be those of a distinct element.

_Uses._ The principal consumption of phosphorus is in the manufacture of lucifer matches. When swallowed, it acts as a powerful corrosive poison; but small doses of its ethereal and oily solutions are occasionally administered in cases of chronic debility, extreme prostration of the nervous powers, impotency, &c. Its action is that of a powerful diffusible stimulant and diuretic; it is also aphrodisiac. Its use requires great caution, and the effects must be narrowly watched. The treatment of poisoning by phosphorus consists of the administration of a powerful emetic and the copious use of mucilaginous drinks. The French practitioners recommend oil of turpentine as the most effective antidote. They administer about a teaspoonful of the turpentine every four hours.

_Concluding Remarks._ From the great inflammability of phosphorus it can only be safely preserved under water. In commerce, it is always packed in tin cylinders filled with water, and soldered up air-tight. The leading points to be observed to ensure success in this manufacture are chiefly connected with the firing. The heat of the furnace should be most slowly raised at first, but afterwards equably maintained in a state of bright ignition. After 3 or 4 hours of steady firing, carbonic and sulphurous anhydride are evolved in considerable abundance, provided the materials had not been well dried in the iron pot; then sulphuretted hydrogen makes its appearance, and next phosphuretted hydrogen, which last should continue during the whole of the distillation. The firing should be regulated by the escape of this remarkable gas, which ought to be at the rate of about two bubbles per second. If the discharge comes to be intercepted, it is to be ascribed either to the temperature being too low, or to the retort getting cracked; and if, upon raising the heat sufficiently, no bubbles appear, it is a proof that the apparatus has become defective, and that it is needless to continue the operation. We may infer that the process approaches its conclusion by the increasing slowness with which the gas is disengaged under a powerful heat; and when it ceases to come over we may cease firing, taking care to prevent reflux of water into the retort (and consequent explosion), from condensation of its gaseous contents, by admitting air into it through a recurved glass tube, or through the tube of the copper adapter. The usual period of the operation, upon the great scale, is from 24 to 30 hours.

=Phosphorus, Amor′phous.= _Syn._ RED PHOSPHORUS, ALLOTROPIC PHOSPHORUS; PHOSPHORUS FUSCUS, P. RUBER. L. This is phosphorus in that peculiar condition to which Berzelius has applied the term “allotropic.” The honour of its discovery is due to Dr Shrötter, of Vienna.

_Prep._ The ordinary phosphorus of commerce, rendered as dry as possible, is placed in a shallow vessel of hard and well-annealed Bohemian glass, fitted with a safety tube just dipping beneath the surface of a little hot water contained in an adjacent vessel; heat is then applied by means of a metallic bath (a mixture of lead and tin), the temperature of which is gradually raised until it ranges between 464 and 482° Fahr., and bubbles of gas escape from the end of the safety tube and catch fire as they come in contact with the air; this temperature is maintained until the amorphous condition is produced, the length of the exposure being regulated by a miniature operation with tubes conducted in the same bath; as soon as this point is reached, the apparatus is allowed to cool, and the amorphous phosphorus, which still contains some unconverted phosphorus, detached from the glass; it is then reduced to powder by careful trituration under water, drained on a calico filter, and, whilst still moist, spread thinly on shallow trays of iron or lead; in this state it is exposed, with frequent stirring, to heat in a chloride of calcium bath, at first gentle, and then gradually increased to its highest limit, and the heat continued until no more luminous vapour escapes; the residuum on the trays is then cooled, washed with water until this last ceases to affect test paper, and is, lastly, drained and dried. To render it absolutely free from unaltered phosphorus, it may be washed with bisulphide of carbon.

On the small scale, common phosphorus may be converted into amorphous phosphorus by simply exposing it for 50 or 60 hours to a temperature of about 473° Fahr., in any suitable vessel from which the air is kept excluded by a stream of carbonic acid, or any other gas which is unable to act chemically on the phosphorus.

By keeping common phosphorus fused at a high temperature, under the above conditions, for fully 8 days, compact masses of amorphous phosphorus may be obtained.

_Prop., &c._ A reddish brown, infusible, inodorous, solid substance, which is reconverted into ordinary phosphorus by simply exposing it to a heat a little above 500° Fahr. It is unaltered by atmospheric air; is insoluble in bisulphide of carbon, alcohol, ether, or naphtha; is non-luminous in the dark below about 390° Fahr.; and does not take fire at a lower temperature than that necessary for its reconversion into the common or crystalline form. The sp. gr. ranges between 2·089 to 2·017, according to the method of preparing it. Its properties render it an admirable substitute for the common phosphorus in the composition for tipping matches, both as regards security from spontaneous ignition and the health of the manufacturers, who when exposed to the fumes of ordinary phosphorus, were very liable to be attacked with caries of the lower jaw.

=Phosphorus, Trichloride of.= PCl_{3}. _Syn._ PHOSPHORUS TERCHLORIDE, PHOSPHORUS CHLORIDE. By gently heating phosphorus, in excess, in dry chlorine gas; or by passing the vapour of phosphorus through a stratum of powdered mercuric chloride, strongly heated in a glass tube. It is limpid, colourless, highly fetid, fumes in the air, and is slowly resolved by water into phosphorus acid and hydrochloric acid. Sp. gr. 1·45.

=Phosphorus, Pentachloride of.= PCl_{5}. _Syn._ PHOSPHORIC CHLORIDE, PERCHLORIDE OF PHOSPHORUS.

_Prep._ By the spontaneous combustion of phosphorus in an excess of dry chlorine; or by passing a stream of dry chlorine into the liquid terchloride. By the first method it is obtained as a white crystalline sublimate; by the second, as a solid crystalline mass. It is volatile; water resolves it into phosphoric acid and hydrochloric acid.

=Phosphorus, Oxychloride of.= PCl_{3}O. _Syn._ PHOSPHORIC OXYCHLORIDE, PHOSPHORIC MONOXYCHLORIDE.

_Prep._ By heating pentachloride of phosphorus with a quantity of water insufficient to convert it into phosphoric acid. It is a colourless, fuming liquid, having the sp. gr. 1·7.

=Phosphorus, Hydride of.= PH_{3}. _Syn._ PHOSPHORETTED HYDROGEN, PHOSPHURETTED HYDROGEN.

_Prep._ 1. Phosphorus acid is gently heated in a retort, and the first portion of the gas collected.

2. From phosphorus (in small lumps) boiled in a solution of hydrate of potassium or milk of lime, contained in a small retort, as before. Take a very small thin retort, capable of holding not more than 1 oz. or 1-1/2 oz. of water; place in this 3 or 4 fragments of the sticks of fused hydrate of potassium, each being about 1/2 inch in length; add as much water as will barely cover them, and then drop in a small fragment of phosphorus, about the size of a horse-bean; apply a very gentle heat with the small flame of a spirit lamp, agitating the retort continually. A pale lambent flame will first appear in the interior, and when this reaches the orifice, and burns in the open air, the retort should be placed on the stand with its beak about an inch under water. Care must be taken not to withdraw the flame of the lamp. When the bubbles of the gas rise to the surface they spontaneously inflame.

3. From phosphide of calcium and dilute hydrochloric acid, as above; or simply from the phosphide thrown into the water.

_Obs._ The gas obtained by methods 2 and 3 is contaminated with the vapour of a liquid phosphide of hydrogen, PH_{2}, which gives to it the property of spontaneous inflammability.

_Prop., &c._ Colourless; very fetid; slightly soluble in water; burns with a white flame; decomposed by light, heat, and strong acids; as commonly prepared, inflames on contact with air, at ordinary temperatures, but when pure, only at the heat of boiling water. Sp. gr. 1·24. It is rendered quite dry by standing over fused chloride of calcium.

=Phosphorus, Suboxide of.= P_{4}O. (Odling.) A reddish-brown powder, formed when a stream of oxygen is forced upon phosphorus, melted beneath the surface of hot water. To purify it from phosphoric acid and free phosphorus, it is washed on a filter with water, then dried by bibulous paper, and finally digested with bisulphide of carbon.

=Hypophosphorous Acid.= H_{3}PO_{2}. By cautiously decomposing a solution of hypophosphite of barium with sulphuric acid, filtering from the precipitate (sulphate of baryta), and evaporating. Dissolve hypophosphite of calcium, 480 gr. in distilled water, 6 fl. oz.; dissolve crystallised oxalic acid, 350 gr., in another portion of distilled water, 3 fl. oz.; mix the solutions and filter the mixture through white filtering paper. Add distilled water carefully to the filtrate till it measures 10 fl. oz., and evaporate this to 8-1/2 fl. oz. The solution thus prepared contains about 10% of terhydrated hypophosphorous acid.

_Prop._ A viscid, uncrystallisable liquid having a strongly acid reaction. It is a powerful drying agent, and forms salts called hypophosphites.

=Ammonium, Hypophosphite of.= (NH_{4})_{3}PO_{2}. _Prep._ Dissolve hypophosphite of calcium, 6 oz., in water, 4 pints; and dissolve translucent sesquicarbonate of ammonium, 7·23 oz. (barely 7-1/4), in water, 2 pints; mix the solutions; filter, washing out the solution retained by the carbonate of lime with water, q. s.; evaporate the filtrate to dryness with great care; dissolve it in alcohol, q. s.; filter, evaporate, and crystallise. Very soluble in both alcohol and water.

=Barium, Hyperphosphite of.= Ba_{3}(PO_{4})_{2}. _Prep._ Boil phosphorus in a solution of hydrate of barium (baryta water) till all the phosphorus disappears and the vapours have no longer a garlic odour. Filter, evaporate, and set aside to crystallise.

=Calcium, Hypophosphite of.= Ca_{3}(PO_{2})_{2}.

_Prep._ Slack recently burnt lime, 4 lbs., with water, 1 gall., and mix it with water, 4 galls., just brought to the boiling temperature in a deep open boiler, stirring until a uniform milk of lime is formed; then add phosphorus, 1 lb., and keep up the boiling constantly, adding hot water from time to time, so as to preserve the measure as nearly as may be until all the phosphorus is oxidised and combined, and the strong odour of the gas has disappeared; then filter the solution through muslin, wash out that portion retained by the calcareous residue with water, and evaporate the filtrate till reduced to 6 pints; re-filter, to remove a portion of carbonate of calcium resulting from the action of the air upon the solution; evaporate again until a pellicle forms, and set aside to crystallise——or continue the heat with constant stirring until the salt granulates.

_Obs._ As spontaneously inflammable phosphuretted hydrogen is given off during the boiling, the process must be conducted under a hood, with a strong draught or in the open air. Smaller proportions than those given may be used.

_Prop._ Hypophosphite of calcium is a white salt, with pearly lustre, crystallising in flattened prisms; soluble in 6 parts of cold water, and slightly soluble in dilute alcohol. It is the most important of these compounds, and when introduced into the stomach it is supposed to be converted into phosphate of calcium. It has been termed ‘chemical food.’ By decomposition it readily furnishes the other hypophosphites.

=Ferric, Hyperphosphite of.= FePO_{2}. _Prep._ By precipitating a solution of hypophosphite of sodium or ammonium, with solution of ferric sulphate, washing the gelatinous precipitate with care (it being somewhat soluble); and, finally, drying it into an amorphous white powder. This is freely soluble in hydrochloric and hypophosphorous acids.

=Potassium, Hypophosphite of.= K_{3}PO_{2}. _Prep._ From hypophosphite of calcium, 6 oz., dissolved in water, 4 pints; and granulated carbonate of potassium, 5-3/4 oz., dissolved in water, 1/2 pint. Mix, filter, and wash the precipitate till the filtrate measures 5 pints. Evaporate till a pellicle forms, then stir constantly, continuing the heat till the salt granulates. A white, opaque, deliquescent body, very soluble in water and alcohol.

=Quinine, Hypophosphite of.= Dissolve sulphate of quinine, 1 oz., in water, by the aid of diluted sulphuric acid; precipitate the alkaloid with ammonia; wash the precipitated quinine and digest it in hypophosphorous acid with heat (the quinine being in excess); after filtering the solution, allow it to evaporate spontaneously till the required salt crystallises. It forms elegant tufts of soft, feathery crystals, which are soluble in 60 parts of water.

=Sodium, Hypophosphite of.= Na_{3}PO_{2}. _Prep._ From hypophosphite of calcium, 6 oz., dissolved in water, 4 pints; and crystallised carbonate of sodium, 10 oz., dissolved in water, 1-1/2 pint. Proceed as in making hypophosphite of potassium, but allowing 6 pints as the measure of the filtrate. If required in crystals, the granulated salt may be dissolved in alcohol sp. gr. ·835, evaporated till syrupy, and set by in a warm place. Crystallises in rectangular tables, with a pearly lustre; is very soluble in water and ordinary alcohol, and deliquesces when exposed to the air.

=Phosphorus, Trioxide of.= P_{2}O_{3}. _Syn._ PHOSPHOROUS ANHYDRIDE; ANHYDROUS PHOSPHORIC ACID.

_Prep._ By burning phosphorus in a limited supply of air. White flaky powder, with an odour of garlic, and rapidly absorbing water to form phosphorous acid.

=Phosphorous Acid.= H_{3}PO_{3}. _Syn._ HYDRATED PHOSPHOROUS ACID. Pure phosphorus is volatilised through a layer of powdered mercuric chloride, contained in a glass tube; terchloride of phosphorus comes over, which, on being mixed with water, is resolved into hydrochloric acid and phosphorous acid; by evaporating the mixed liquid to the consistence of a syrup, the first is expelled, and the residuum forms a crystalline mass of hydrated phosphorous acid on cooling.

_Prop., &c._ It is a powerful deoxidising agent. Heated in a closed vessel, it is resolved into hydrated phosphoric acid and pure phosphuretted hydrogen gas. With the bases it forms salts, called phosphites, which possess little practical importance.

=Phosphorous Pentoxide Acid.= P_{2}O_{5}. _Syn._ ANHYDROUS PHOSPHORIC ACID; PHOSPHORIC ANHYDRIDE; PHOSPHORIC OXIDE. By the vivid combustion of phosphorus in a stream of dry atmospheric air, or under a bell-jar, copiously supplied with dry air. The product is pure anhydrous phosphoric acid under the form of snow-like flakes. It must be immediately collected and put into a warm, dry, well-stoppered bottle. In this state it exhibits an intense attraction for water, and when thrown into it combines with explosive violence; exposed to moist air for only a few seconds, it deliquesces to a syrupy-looking liquid.

=Phosphoric Acid.= There are three distinct acids usually grouped under this head, namely, METAPHOSPHORIC ACID, HPO_{3}; PYROPHOSPHORIC ACID, H_{4}P_{4}O_{7}; and ORTHOPHOSPHORIC ACID, H_{3}PO_{4}.

=Metaphosphoric Acid.= HPO_{3}. _Syn._ MONOBASIC PHOSPHORIC ACID; GLACIAL PHOSPHORIC ACID.

_Prep._ Bones (calcined to whiteness and powdered), 3 parts, are digested for several days in oil of vitriol, 2 parts, previously diluted with water, 6 parts, the mixture being frequently stirred during the time; a large quantity of water is next added, the whole thrown in a strainer, and the residual matter washed with some hot water; the mixed liquors are then precipitated with a solution of carbonate of ammonium, in slight excess, filtered from the insoluble, finally ignited in a platinum crucible.

By acting upon the anhydride with cold water.

When phosphoric acid is added to a strong solution of phosphate of zirconium, and the mixture, after concentration, is exposed to a low temperature, prismatic crystals are deposited. These, after being strongly heated to expel their basic water, are pure metaphosphate of sodium. From the solution of this salt in cold water, a solution of pure metaphosphoric acid may be obtained, as above, by means of nitrate or acetate of lead and sulphuretted hydrogen.

_Obs._ This acid precipitates the salts of silver white, and is distinguished from the other modifications of phosphoric acid by the property which its solution possesses of coagulating albumen.

=Pyrophosphoric Acid.= H_{4}P_{2}O_{7}. _Syn._ DIBASIC PHOSPHORIC ACID. By strongly heating common orthophosphate of sodium. The water of crystallisation only is at first expelled, and the salt becomes anhydrous; but as the temperature reaches that of redness the salt loses water and is decomposed. By solution of the altered salt in water, crystals of pyrophosphate of sodium may be obtained. A solution of this last compound, treated with nitrate of lead, and the resulting precipitate, suspended in cold water, and decomposed by sulphuretted hydrogen, yields a solution of pure pyrophosphoric acid.

_Obs._ Heat resolves this into a solution of the ordinary acid. Pyrophosphoric acid precipitates the salts of silver of a white colour. The salts of this acid are called pyrophosphates.

=Orthophosphoric Acid.= H_{3}PO_{4}. _Syn._ TRIHYDRIC PHOSPHATE, TRIBASIC PHOSPHORIC ACID. Ordinary nitric acid is heated in a tubulated retort connected with a receiver, and small fragments of phosphorus are dropped into it, singly and at intervals; as soon as the oxygenation of the phosphorus is complete, the heat is increased, the undecomposed acid distilled off, and the residuum evaporated to the consistence of a syrup. In this state it forms the phosphoric acid of the shops. Commercial phosphate of sodium is dissolved in water and the solution precipitated with another of acetate of lead; an abundant white precipitate (phosphate of lead) falls; this is collected on a filter, well washed, and, whilst still moist, is suspended in distilled water, and sulphuretted hydrogen gas passed into it, in excess; a black insoluble precipitate forms, while pure tribasic phosphoric acid remains in solution, and is easily deprived of the residual sulphuretted hydrogen by a gentle heat. By concentration _in vacuo_ over sulphuric acid, it may be obtained in thin crystalline plates.

The solution of this acid may be boiled without change, but when concentrated and heated to about 400° Fahr. it is converted into pyrophosphoric acid, and at a red heat into metaphosphoric acid. Its salts are the ordinary phosphates, or orthophosphates, and they give a yellow precipitate with nitrate of silver.

_Tests._ The following reactions characterise the ordinary or other phosphates:——1. Chloride of barium produces in aqueous solutions of the neutral and basic phosphates a white precipitate, which is insoluble in either hydrochloric or nitric acid, and with difficulty soluble in a solution of chloride of ammonium.——2. Solution of sulphate of calcium produces in neutral and alkaline solutions of the phosphates a white precipitate, freely soluble in acids, even the acetic.——3. Sulphate of magnesium produces in solutions of the phosphates, to which some chloride of ammonium and free ammonia has been added, a white, crystalline, and quickly subsiding precipitate of the phosphate of ammonium and magnesium, which is insoluble in a solution of either ammonia or chloride of ammonium, but readily soluble in acids, even the acetic.——4. Nitrate of silver, with neutral and basic alkaline phosphates, gives a light yellow precipitate. If the fluid in which the precipitate is suspended contained a basic phosphate, it does not affect test paper; if it contained a neutral phosphate, the reaction will be acid. If the phosphate examined has been heated to redness before solution, it then, as a metaphosphate, gives a white precipitate with nitrate of silver.——5. Hydrochloric acid is added to the solution to acid reaction, and afterwards 1 or 2 drops of a concentrated solution of ferric chloride; a solution of acetate of potassium is next added in excess, when a flocculent, gelatinous, white precipitate will be formed if phosphoric acid or any phosphate was present in any form or combination in the original liquor. This test is highly characteristic, and of general applicability.

_Obs._ The insoluble phosphates must be first treated with diluted hydrochloric or sulphuric acid, and the resulting solution filtered and neutralised with an alkali, before applying the reagents. When the substance under examination consists of a very small quantity of phosphoric acid or phosphate, with a large quantity of sesquioxide of iron, it should be fused with some carbonate of sodium, the residuum of the ignition exhausted with water, and the tests applied to the filtered solution. Arsenious acid, if present, should be removed by sulphuretted hydrogen before applying the tests. When phosphate of aluminum, the solution in hydrochloric acid is neutralised with carbonate of sodium; carbonate of barium is next added in excess, followed by the addition of hydrate potassium, also in excess, after which the whole is boiled. An insoluble phosphate of barium is formed, which may be decomposed by sulphuric acid, as before. See MOLYBDATE OF AMMONIUM.

_Estim._ Pure solutions of phosphoric acid may be tested by the common methods of acidimetry. When in a state of combination, it may be separated and weighed in either of the forms noticed under GUANO.

_Uses, &c._ This acid is the common form, and is the compound alluded to when ‘phosphoric acid’ is spoken of. It is extensively employed by the bleacher, dyer, calico-printer, and enameller. Unlike sulphuric acid and the other strong acids, it does not coagulate albumen nor injure vegetable fibre, and is not decomposed by contact with organic matter. In combination with alumina and a large boracic acid, it is said to be capable of producing a glaze for earthenware of extreme beauty and durability, and perfectly innocuous. It is also used in medicine.

PHOSPHORIC ACID, DILUTED. (B. Ph.) Put 6 fl. oz. of nitric acid (sp. gr. 1·42), diluted with 8 oz. of distilled water, into a tubulated retort connected with a Liebig’s condenser, and having added 413 gr. of phosphorus, apply a very gentle heat until 5 fl. oz. of liquid have distilled over. Return this to the retort, and renew and continue the distillation until the phosphorus has entirely dissolved.

Transfer the contents of the retort to a porcelain capsule and evaporate the liquid until it is reduced to 4 fl. oz. Transfer to a platinum vessel and evaporate to about 2 fl. oz., and until orange vapours cease to form. Mix when cool in such an amount of distilled water that the volume shall become one pint. (It contains 10 per cent. by weight of anhydrous acid. Sp. gr. 1·08.)——_Dose_, 10 to 30 minims properly diluted.

=PHOSPHORUS, BALDWIN′S.= Recently fused nitrate of calcium. For this purpose it must be broken into fragments whilst still warm, and at once placed in dry and well-stopped phials. After exposure for some time to the direct rays of the sun it emits sufficient light in the dark to render visible the figures on the dial-plate of a watch.

=PHOSPHORUS, BOLOGNIAN.= _Syn._ KERCHER’S PHOSPHORUS, BOLOGNIAN STONE. This substance was accidentally discovered by a shoemaker of Bologna, and excited much interest about the middle of the 17th century. The following is said to have been the formula employed by the Logani family, who were particularly successful in its preparation, and acquired wealth by its sale to the curious throughout Europe.

_Prep._ Reduce recently calcined native sulphate of barium to powder, make it into a paste with mucilage of gum tragacanth, and roll the mass into pieces about 1/4 inch thick and 1 to 2 inches long; dry these slowly by a moderate heat, and then expose them to ignition in a wind furnace, by placing them loosely among the charcoal; lastly, allow them to cool slowly, and at once place the pieces in well-stopped phials. Like the preceding substance, it phosphoresces in the dark after exposure to the sun’s rays.

=PHOSPHORUS, CANTON′S.= _Prep._ From calcined oyster shells, 3 parts; flowers of sulphur, 1 part; placed in alternate layers in a covered crucible, and exposed to a strong heat for about an hour. It is preserved and used like the above.

=PHOSPHORUS, HOMBERG′S.= Recently ignited chloride of calcium.

=PHOSPHORUS BOTTLES.= _Prep._ 1. Phosphorus, 12 gr.; olive oil, 1/2 oz.; mix in an oz. phial, and place the latter, loosely corked, in a basin of hot water; as soon as the phosphorus is melted, remove the phial, cork it securely, and agitate it until nearly cold. On being uncorked it emits sufficient light in the dark to see the time by a watch, and will retain this property for some years if not too frequently employed. These are frequently called ‘luminous phials.’

2. (BRIQUETS PHOSPHORIQUES.)——_a._ From phosphorus, 3 parts; white wax, 1 part; cautiously melted together by the heat of hot water; as the mixture begins to cool, the bottles are turned round, so that it may adhere to the sides.

_b._ (Bendix.) Cork (rasped small, and dry) and yellow wax, of each 1 part; phosphorus, 4 parts; petroleum, 8 parts; mixed, by fusion, as the last.

Used as instantaneous-light bottles. A sulphur match rubbed against the composition immediately inflames on exposure to the air. They should be only unstoppered at the instant of introducing the match, and should be handled with caution.

=PHOSPHORUS MATCHES.= See MATCHES, and _above_.

=PHOSPHORUS PASTE.= _Syn._ ANTI-ARSENICAL RAT-POISON, PHOSPHOR-PASTE. _Prep._ 1. Phosphorus, 1 oz.; warm water, 1 pint; place them in a bottle, cork it, and agitate them well together, until the phosphorus is reduced to a minute state of division, adding towards the end moist sugar, 1/2 lb.; next add of lard (melted by a gentle heat), 1 lb., and repeat the agitation until the whole is nearly cold; when cold, form it into a stiff dough with oatmeal or barley meal, and make this into small balls or cakes; lastly, dry these in the air, without artificial heat.

2. (Simon.) Phosphorus, 8 parts; water (lukewarm), 180 parts; mix in a mortar, and add of rye meal, 180 parts; when cold, further add of butter or lard, 180 parts; sugar, 125 parts; and mix the whole thoroughly together. This is the formula authorised by an ordinance of the Prussian Government, dated April 27th, 1843.

_Obs._ Rats, mice, &c., eat the above composition with avidity, after which they soon die. It is said that the best method of using it is to place small pieces of it in and about the holes, with some water in a shallow vessel for them to drink. It has the advantage of retaining its efficacy for many years, and is less dangerous to human beings than compositions containing arsenic, whilst it is even more effective for the purpose for which it is employed. Some persons recommend the addition of a little oil of rhodium or oil of aniseed. See RATS, &c.

=PHOS′PHURET.= _Syn._ PHOSPHIDE; PHOSPHORETUM, PHOSPHIDUM, L. A compound of phosphorus with a metal or other basic radical. See the respective METALS, &c.

=PHOSPHURETTED HY′DROGEN.= _Syn._ PHOSPHORETTED HYDROGEN. See HYDROGEN.

=PHOSPHATIC DIATHESIS.= _Syn._ WHITE GRAVEL. A morbid condition of the system, characterised by the deposition in the urine of certain salts of phosphoric acid or phosphates. In this affection the urine, contrary to its normal condition, is always alkaline, and the nature of the phosphatic deposit is influenced by the source of the alkalinity. If, as most frequently happens, this is owing to the presence of carbonate of ammonia (formed by the decomposition of the urea by the bladder mucus), the deposit will be found to consist of the triple phosphate, or phosphate of magnesia and ammonia, almost always associated with a small quantity of amorphous phosphate of lime. Under these circumstances the urine is pale in colour, and upon standing soon decomposes, in doing which it gives off a strong ammoniacal odour. Phosphatic diathesis is a frequent accompaniment of spinal affections and of chronic inflammation of the mucous lining of the bladder.

In mild attacks the best treatment consists in living rather generously, and in the administration of vegetable tonics combined with proper doses of the mineral acids.

=PHOTOG′RAPHY.= _Syn._ HELIOGRAPHY. The art of producing images on prepared surfaces by means of the actinic or chemical rays of the sun’s light. The principal photographic processes now in use are the positive-, negative-, and dry-collodion processes, in each of which a thin film or skin of iodised collodion forms the sensitive surface, a plate of glass being generally used as the foundation of the film. In a positive picture the ‘lights’ are silvery white by reflected light, and the ‘shades’ are produced by a ‘backing’ of black varnish or velvet, showing through the glass plate. In a negative picture the ‘lights’ are of a dirty yellow or brown by reflection, and being formed by opaque deposits, appear dense black by transmitted light. Negatives are used in the various paper-printing processes; they are placed upon prepared paper and exposed to direct light, which darkens those parts of the paper not protected by the opaque ‘lights,’ and thus produces positive prints with natural lights and shades. In this way the portrait ‘cartes de visite’ and other paper photographs are formed.

Of late years there have been devised a great variety of new photographic processes, some of which are given below, together with modern formulæ for the principal solutions, &c., in general request by the photographer.

The Daguerreotype process, discovered by M. Daguerre in 1839, has been entirely superseded by the easier, healthier, and less expensive collodion processes described further on. It consists in submitting a plate of silver or silvered copper to the vapour of iodine and bromine in the dark. A sensitive film of iodide and bromide of silver is thus formed on the plate, which is immediately exposed to the image of an object in the camera obscura. The latent image impressed on the plate is brought out or developed by exposing the plate to the action of the vapour of mercury.

It is to be noted that in all English photographic formulæ the solid and fluid measures of apothecaries weight are used; but in buying or selling chemical articles, the avoirdupois weight is employed.