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.
[Illustration]
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.
_Nitrate of Silver Bath_ (_for Positives_). Recrystallised nitrate of
silver, 5 dr., dissolved in 10 oz. of distilled water. Filter the solution
until it is quite clear, then add 3 drops of nitric acid and 10 drops of
collodion. Shake well together and filter. Blue litmus paper should
slightly redden in this bath; should it turn very red, add a little
ammonia, or oxide of silver; should it not redden at all, add a little
acid carefully drop by drop. It is preferable to have a slight excess of
acid.
_Developing Solution_ (_for Positives_). Protosulphate of iron, 2 dr.,
dissolved in 8 oz. of distilled water; add 2-1/2 dr. of glacial acetic
acid, 2-1/2 dr. of alcohol, and 5 minims of nitric acid, filter, and pour
into a well-stoppered bottle; do not expose to the air.
_Fixing Solution_ (_for Positives_). 50 gr. of cyanide of potassium
dissolved in 5 oz. of distilled water; that is to say, for every fluid
ounce of solution required, mix 10 gr. of cyanide of potassium in 1 oz. of
distilled water. Filter and keep in a well-stoppered bottle, and label
“Poison.”
_Positive Paper._ Plain paper requires preparing or salting before it is
ready for use, or it may be purchased already salted.
Procure some sheets of plain Saxe paper, and immerse them for five minutes
(removing air-bubbles) in the following solution:——
Chloride of ammonium 100 gr.
Chloride of barium 100 gr.
Citrate of soda 20 gr.
Water 20 oz.
Hang the sheets up to dry. For portraits and most other uses the paper is
albuminised on one side. When photographs are printed to be afterwards
coloured, unalbuminised paper is used.
_Albuminised Paper._ There are several well-known papers sold; _Rive’s_,
which is a French paper, has a high glaze and fine surface; the _Saxe_,
which is more uniform in its texture, is made in Germany. Another maker is
_Towgood_. Positive paper is albuminised by placing it in a mixture
composed of white of eggs and salt. To the white of each moderate-sized
egg use 15 gr. of common salt reduced to a fine powder; whisk until the
albumen is all white froth. Leave this froth in a glazed earthen pan for
about 12 hours, by which time most of it has settled into clear albumen;
pour the clear portion into a flat porcelain tray. This tray should be
somewhat larger than the sheets of paper to be albuminised. Lift the paper
up by the ends and lay it carefully on the albumen, keeping the side
marked as “inferior” uppermost and dry.
The paper should be slightly damp before it is thus treated, as it then
takes the albumen more regularly, and is not so liable to air-bubbles. The
paper must be lifted at each end, and should any air-bubbles appear,
brush them off with a card or small brush, replacing the paper in the
bath. Wherever the albumen does not come into actual contact with the
paper, a white mark will appear in the print. Remove the paper from the
bath and place it to dry on a cardboard frame, or suspend it at the
corners by clips. Paper glazed with pure albumen acquires too brilliant a
glaze for portraits; the albumen may be diluted with from a 1/4 to 1/3 its
bulk of water. It should be kept in tin or zinc cases.
_Plain Paper._ Albuminised paper may be used as plain paper if, instead of
sensitising the glazed side, the plain side is placed in the sensitising
solution.
_Nitrate of Silver Bath_ (_for Negatives_). Recrystallised nitrate of
silver, 1/2 oz.; distilled water, 7 oz.; collodion, 7 drops. Shake well
together until the crystals have dissolved, then filter.
The purity of the negative bath is a matter of great importance, hence the
necessity of employing the very best nitrate of silver, and also of
excluding all foreign matters of every kind. When the bath gets out of
order, it should be diluted with an equal bulk of distilled water, and
exposed to the sun for a few days, in a white glass bottle, then filtered,
and sufficient nitrate of silver added to restore the strength to 35
grains an ounce, as indicated by the argentometer.
_The Argentometer._ This instrument is for ascertaining the strength of
the nitrate of silver solution, which becomes weakened to a certain
extent, after the immersion of every plate.
_Developing Solution_ (_for Negatives_). Protosulphate of iron, 75 gr.;
glacial acetic acid, 2 dr.; alcohol, 2 dr.; distilled water, 5 oz.
Dissolve the crystals in the water, then add the acid and alcohol, and
filter. In hot weather a little more acetic acid may be added, and if it
does not flow readily, the alcohol may be increased.
_Intensifying Solution_, No. 1 (_Negatives_). Pyrogallic acid, 10 gr.;
citric acid, 10 gr.; distilled water, 5 oz. When it becomes brown it is
useless. No. 2. Recrystallised nitrate of silver, 40 gr.; distilled water,
1 oz.; dissolve and filter. This latter will keep for any length of time
in the dark.
_Another Intensifying Bath_ (_Negatives_). A saturated solution of
bichloride of mercury in water. Place the negative plate in a bath of the
solution, remove when the film assumes a milky-white appearance, wash, and
then plunge into a solution of 1 oz. of liquid ammonia to 10 oz. of water.
Remove the plate, wash, and place to dry. This mode of intensifying may be
regulated by leaving the plate in the bichloride of mercury a shorter
time, when it will require a weaker ammonia bath than that above given.
_Fixing Solution_ (_for Negatives_). Hyposulphite of soda, 5 oz.;
distilled water, 5 oz.; dissolve and filter.
_Sensitising Solution_ (_for Paper_). Nitrate of silver, 5 dr.; distilled
water, 5 oz.; nitric acid, 2 drops; kaolin, 1 oz. Dissolve the nitrate of
silver in the water, and then add the acid and kaolin; the kaolin will not
dissolve, its use being to prevent the solution becoming discoloured after
using. This solution will not require filtering; it must be allowed to
become quite clear, and when required for use must be carefully decanted.
This solution should be occasionally tested with the argentometer, and
sufficient nitrate of silver added to restore it to its original strength.
_Another Negative Collodion._ Ether, 1/2 oz.; gun-cotton, 7 gr.; bromide
of cadmium, 1/2 gr.; bromide of ammonium, 1-1/2 gr.; iodide of calcium, 1
gr.; iodide of potassium, 1 gr.; iodide of ammonium, 1 gr. For
intensifying, flood with chloride of gold, 1 gr.; water, 15 oz.; then
wash, and flood with pyrogallic acid, 2 gr.; water, 3 oz.
_Toning Baths._ 1. Chloride of gold, 4 gr.; acetate of soda, 1/4 oz.;
distilled water, 10 oz.; dissolve and filter. 2. _To produce black to
bright sepia tones, according to length of immersion._ Take carbonate of
soda sufficient to cover a threepenny piece, dissolve it in a teaspoonful
of cold water in a cup, add 2 gr. of chloride of gold, then add 3 oz. of
boiling water; use in 15 minutes. This will suit Hart’s albuminised paper.
_Fixing Solution_ (_for Paper Prints_). Hyposulphite of soda, 8 oz.;
distilled water, 1 pint. This solution must only be used once.
_Stopping-out Negatives._ Small, round, transparent spots are frequently
found on glass negatives, which, if not stopped, occasion corresponding
black spots on the print. Lay the plate on a slab of glass, having either
direct or reflected light shining up through it. Then cover the spots with
a mixture composed of 10 parts of ivory black, 2 parts of saturated
solution of gum Arabic, 2 parts of white honey, 1 part of sugar-candy;
well mix and apply with a fine camel-hair brush. Should the spots on the
negative be black or opaque, white spots will be formed on the print;
these are easily tinted with a little water colour, to match the other
portions of the print; it is seldom necessary, therefore, to alter the
negative on this account.
_Ferrotypes._ In these, instead of a glass plate being used to receive the
picture, as in a positive glass photograph, a thin plate of black
varnished iron is employed. Of course no black backing is required; with
this exception the photograph is produced in every particular by the same
means and in the same manner as the glass positive is.
_To Clean Glass Plates._ (Mr Hughes.) The description of glass known as
“flatted crown” is well suited for positives, but before using it requires
careful cleaning. The sharp edges should be first removed with a
“corundum” file, or by drawing the sharp edge of one piece over the sharp
edge of another; then place the glass on a clean flat surface, or put it
in “a plate-cleaning holder,” and pour a few drops of the plate-cleaning
solution in the middle. Rub it carefully over every part with a bit of
clean soft rag; turn the glass over, and do the other side the same. Then
polish each side with a clean cloth, and finish with a soft chamois
leather kept expressly for this purpose. Now breathe on the glass, and if
the breath deposits evenly the plate is clean. If the plate, however,
shows patches and marks, it must be recleaned. Let the edges be carefully
wiped, and the plate is ready for use.
The following preparation makes a good plate-cleaning solution for glasses
that require mechanical friction to make them clean:——Ordinary water, 5
oz.; alcohol, 5 oz.; iodide of potassium, 15 gr.; iodine, 3 gr. When
dissolved, add tripoli, prepared chalk, whiting, or rotten-stone, in
sufficient quantity to make a creamy paste.
This thin pasty solution is to be rubbed on the plates on both surfaces
and polished off as already described. This amount of cleaning will
generally be sufficient for new glasses, but when they have been used they
require more labour.
They must then be well washed under the tap, to get rid of all collodion
and chemicals, and be wiped on cloths kept expressly for the purpose.
Should the plates have been varnished they must be soaked for some hours
in a saturated solution of washing soda till the varnish and film come
freely off. The glasses must then be immersed for a few minutes in a
solution composed of common nitric acid, 2 oz., water, 10 oz., and be well
washed and treated as already described. It is a good plan when working to
have a dish of water at hand, and to place the spoilt pictures in it at
once while they are wet, and at the end of the day to wash the glasses and
put them away clean. By thus not allowing the films to dry on the glasses
they are much easier cleaned, and fewer failures will arise from dirty
glasses.
Collodion is a good material for cleaning glasses when they are not very
dirty. Pour a few drops on the glass and well rub it with a clean cloth,
and you will entirely remove all grease; a hint may thus be taken how to
use up waste collodion.
_Various Solutions used in the Dry Process._ These are employed in cases
where bromo-iodised collodion and the nitrate bath are used.
In all processes in which the bromo-iodised collodion is employed 2 grains
of bromide of cadmium should be added to each ounce of the collodion.
Mr Bartholomew advises diluted alcohol to be poured over the plate
previous to developing.
_Acid Pyro Developer._ This developer is formed as follows:
Pyrogallic acid 1 gr.
Glacial acetic acid 30 minims.
Water 1 oz.
The plate, after being wetted with dilute alcohol and washed, has this
solution flowed over it, to which has been added 2 or 3 drops of a
10-grain nitrate of silver solution.
_Plain Pyro Developer._ The strength of this may vary from 1 to 5 gr. in
an ounce of water. Two grains may be taken as a medium. The dry plate
being flooded with alcohol and water, and washed so as to well wet the
film, this solution is floated over it.
_Alkaline Pyro Developer._
No. 1.——Pyrogallic acid 96 gr.
Absolute alcohol 1 oz.
No. 2.——Carbonate of ammonia 96 gr.
Water 1 oz.
No. 3.——Bromide of potassium 10 gr.
Water 1 oz.
At the time of using, make up the following solution:
Water 1 oz.
Solution No. 1 10 minims.
Solution No. 3 5 ”
Pour this over the wetted plate, allow it to remain on a few seconds only,
and then pour back into the developing cup, and add to it 5 minims of
solution No. 2, and apply again.
_The Collodio-Albumen Dry Process._ (Mr Mudd.) In this process the
ordinary bromo-iodised collodion is employed. The plate being sensitised
is washed well first with distilled, then with common water, and placed in
a dish half filled with solution of iodide of potassium (3 gr. to the
oz.), and allowed to remain while the next plate is being prepared. It is
then removed from the solution and well washed with clean water, after
which the following solution is poured over its surface:
Distilled water 2-1/2 oz.
White of eggs 10 oz.
Iodide of potassium 50 gr.
Bromide of ammonium 10 gr.
Strongest solution of ammonia 120 minims.
Introduce these materials with some pieces of broken glass into a bottle
capable of holding twice the quantity, and agitate till the whole forms a
froth, and then, when settled, it is ready. A piece of camphor placed in
the solution will help to preserve it. It must be filtered before using.
After the plate has been coated with the above it is finished by drying
before the fire.
In this process all the above operations may be performed in ordinary
white light. To render the plate sensitive, heat it as hot as the hand
will bear, and when cool immerse it again in the following aceto-nitrate
of silver bath for one minute, using only a yellow light, then wash
thoroughly in clean water, and dry in the dark.
Nitrate of silver 30 gr.
Distilled water 1 oz.
Glacial acetic acid 1/2 dram.
The development may be commenced by either plain or alkaline pyro; Mr Mudd
gives the preference to the plain, and intensifying after with acid
silver.
Dr RYLEY’S _Modified Collodio-albumen Dry Process_. In this method the
plate has to be sensitised as usual, and washed thoroughly. When the plate
has been well drained, and while still wet, it is coated with the
following solution:
Albumen 1 oz.
Water 2 oz.
Ammonia 30 minims.
The solution is beaten to a froth, allowed to settle, and filtered before
using. Pour sufficient over the plate to cover it, letting it flow
backwards and forwards so as to soak into the film. Pour the albuminous
solution away and thoroughly wash the plate, the last rinsing being with
distilled water. Let the plate dry; when perfectly dry, moisten the plate
with distilled water, and pour over the following solution:
Gallic acid 2 gr.
Water 1 oz.
Filter the solution before using. Pour it on and off the plate to well
permeate the film, then set the plate up to drain, and dry without washing
off the gallic acid solution. When the surface is dry finish by the heat
of a dull fire.
_Bromide of Silver, Wet Process._ To every ounce of good collodion add 8
gr. of bromide of cadmium. The nitrate bath must be made 80 gr. to the
oz., and slightly acidulated with nitric acid. The plate must remain in
the bath the full time it requires to form a dense opaque film. When the
plate is ready (it must not be removed from the bath until the film is
much denser than in the ordinary wet process) it must be washed thoroughly
to remove all silver. It must then have poured over it a 3-grain solution
of gelatin made slightly alkaline with carbonate of soda, or diluted
albumen (albumen, 1 oz.; water, 4 oz., well beaten together). When the
plate is in this condition it may be exposed wet, or it may be allowed to
dry. Prior to development it must be well washed, and the alkaline method
must always be adopted. If the plates are used dry, a preliminary coating
of dilute albumen is necessary, but if used wet, this is not necessary.
_Bromide of Silver, Emulsion Process._ By this method the nitrate bath is
not necessary, as the sensitive material is contained in the collodion.
The purchase of the material ready-made for working this process is
recommended in preference to its direct manufacture, as its preparation
demands the use of considerable technical skill, together with the
employment of a gun cotton not usually attainable. Mr Hughes says the
‘Liverpool Dry Plate Company’ supply an excellent emulsion. It is only
necessary to pour the emulsion on to a plate and to allow it to dry, when
the plate is ready for use. The development is by the alkaline process.
_Gelatino-bromide of Silver, Emulsion Process._ In this process the use
both of the nitrate bath and of collodion are abolished.
The material employed is very troublesome to prepare, and on this account,
as well as because of the risk of failure attending the use of home-made
articles, it is far preferable it should be purchased. It may be obtained
under the name of ‘Kennett’s Sensitised Pellicle.’
This pellicle consists of shreds of dry gelatin containing the sensitive
salts.
Fresh directions accompany each packet of the “Sensitised Pellicle.”
_The Honey Process._ Let the plate be cleaned, coated, and sensitised in
the usual manner; then place it in a bath of distilled water, washing it
more or less, as it may be required to be kept for a longer or shorter
time. Pour on the plate a solution made of equal parts of honey and
distilled water in the same manner as when using collodion; throw away the
first portion, and repeat the operation, letting the solution soak in for
one or two minutes; pour back the honey solution into its bottle; drain
the plate on blotting paper, and keep it in the dark free from dust. The
time required for exposure of the plate is about double as long as in the
ordinary wet process.
The plate should be soaked in distilled water previous to being developed,
in order to soften or remove the film of honey; the older the plate the
longer it will require to be soaked, afterwards dip the plate in the
silver bath, and develop in the usual manner.
_The Carbon Process._ In this process, the adoption of which is daily
increasing, the material employed consists of a layer of gelatin
containing carbon, or some other permanent pigment, spread on paper.
In this condition the paper is not sensitive to light, but if it be
treated with a solution of bichromate of potash, dried in the dark, and
afterwards exposed to sunlight under a negative, those portions of the
paper which have been acted upon by the light will become insoluble,
whilst those parts that have been protected from it will be soluble. When,
therefore, after sufficient exposure, the prepared paper is removed from
the negative, a picture the reverse of the negative will have been formed,
in which the pigmented gelatin alone remains, and performs the part of the
reduced silver in the ordinary photograph.
If the film, after exposure to light under a negative, is soaked in warm
water, all the parts which have been protected from the action of the
light can be dissolved, and a relief is formed which, when dry, is
sufficiently hard to transmit its shape to lead. From the mould or plate
thus obtained a comparatively large number of impressions can be taken,
either with coloured gelatin or with fatty colours, the well-known
Woodbury-type being the most successful of the several processes based on
the fact.
=Photographic Varnish.= See VARNISHES.
MISCELLANEOUS RECIPES:
_To Clean Glass Plates._ (Mr Mayall.) Shake up together alcohol, 30 parts;
strong liquid ammonia, 10; water, 40; and fine tripoli, 30 parts. The
plates are to be rubbed hard and evenly with balls of cotton wool dipped
in this mixture. Rub again, when dry, with a clean ball of cotton; lastly,
dust the back and edges with a clean hog-hair brush.
_To Clean off Collodion Pictures._ This may be done whether they have been
varnished or not, by means of a tuft of cotton wool dipped in wood spirit.
_To Colour Photographic Prints._ This may be done variously in water and
oils. A simple way is to rub in slowly with a small camel-hair brush a
minute piece of dry colour laid upon the part, as of flesh tint for the
face, &c. When properly distributed, the paper may be breathed upon, and
the tint will not easily be rubbed off. Or it may be carefully coated with
gelatin.
M. Minotto has described a plan of colouring on the back of the paper. The
picture, being held up to the light, is first faintly outlined, on the
reverse side; colours are then laid on, of water or oil, as preferred, on
this side. When dry the paper is rendered transparent by a varnish, and
the colours will then appear through it with all the delicacy and effect
of a miniature on ivory. Good strong writing paper is best for this
purpose; the colours must be vivid; and the varnish may consist of Canada
balsam dissolved in turpentine, or a mastic varnish may be used, or
turpentine and wax, or oil.
_To Remove Stains from the Hands._ The powerfully poisonous character of
cyanide of potassium renders its employment for the above purpose an
operation attended with considerable danger. Iodide of potassium and
iodine may both be substituted, but the first is expensive, and the second
requires considerable nicety in its application, lest a coloured stain be
left on the skin. Instead of the above substances, M. Fortin recommends to
wash the hands with a concentrated solution of either sulphate or chloride
of zinc, to which some acid is added at the same time. He advises the
deepest and blackest stains being touched with metallic zinc, whereby the
reduction of the oxide of silver or that of the gallate of iron is
promoted, and all metallic stains adhering to or penetrating into the skin
removed. Since most of the salts of zinc are colourless, and soluble in
water, the hands soon become quite clean. They should then be washed,
first with pure water, and next with soap and water.
The reader desirous of further information on the subject of photography
cannot do better than consult Mr Ernest Spon’s valuable manual, entitled
‘Workshop Receipts,’ and Mr Hughes’ ‘Principles and Practice of
Photography,’ to both of which we are largely indebted. Captain Abney’s
work on ‘Photography,’ cannot be too highly commended. See COLLODION,
PHOTOGRAPHIC.
=Photographic Waste Products, Recovery of.= We extract the following from
the ‘American Chemist’ for February, 1876. The contributor, Mr. C. A.
Pitkin, A. B., states that the methods given have been collected from the
‘Philadelphia Photographer,’ the ‘British Photographic Journal,’
Hardwick’s ‘Photograph Chemistry,’ &c., &c.; also that they include
suggestions by Professor Hill.
1. Nitrate bath, α, recovered; β, renovated.
2. Hyposulphite bath.
3. Reduction of silver chloride, oxide, or sulphide.
4. Gold waste, α, recovered; β, separated from silver,
5. Paper waste and washings from positive prints.
6. Cyanide solution.
7. Developer.
I. _Nitrate Bath_,
α, _Recovered_.
1. Add solution of caustic potash or lime, as long as there is a brown
precipitate. Allow to settle, pour off liquid, and collect silver oxide
for reduction; _vide_ III, below.
2. For 1 lb. of silver, add 1 oz. sulphuric acid and 1/2 lb. zinc, and
allow to stand two days. Precipitate as chloride, wash eight or ten times
by decantation, and dissolve gradually in nitric acid.
NOTES.——Test complete washing by hydrochloric acid. Wash with water till
zinc nitrate is removed. If zinc clings to silver wash with hydrochloric
acid.
3. Suspend sheet of copper in bath for two or three days.
4. Acidify as nitric acid, precipitate as silver chloride by sodium
chloride or hydrochloric acid, and reduce as _vide_ III, below.
5. Immerse in bath two strips of copper attached to the poles of a
Daniell’s or Smee’s cell. Silver deposited on the copper as in 3, above.
6. Add sodium bicarbonate or sodium hydrate. Reduce as 3 below, or if pure
enough, dissolve precipitate at once in nitric acid.
7. Concentrate bath, make alkaline by sodium carbonate, and add aqueous
solution of oxalic acid neutralised with sodium carbonate. Filter, dry,
and fuse with equal weight of sodium bicarbonate.
8. Deposit, either with or without battery, on iron. (Iron can be obtained
purer than zinc or copper, and possesses the additional advantage that the
iron salts, as iodides, &c., are all quite soluble). Fuse with potassium
nitrate and sodium carbonate.
β. _Renovated._
1. Dilute with three volumes of distilled water, expose to sunlight,
filter, add sodium carbonate till slightly turbid. Expose to sunlight six
hours more, filter, add sodium carbonate till silver all thrown down.
Wash, precipitate by decantation, and dissolve in nitric acid. Filter
again, make up to 35 grammes; neutralise, expose to sun a week, and bath
is ready for use.
2. Neutralise with ammonia till just alkaline; boil till black; let cool,
filter, acidify with pure nitric acid, and evaporate to crystallisation,
then fuse. When cool, add distilled water, shake and let stand exposed to
light. Filter and add drained crystals. Dissolve and make solution acid
with pure nitric acid. Expose again to sunlight, filter, and bath is ready
for use.
3. Add potassium permanganate, expose to sunlight, filter, acidify, put in
clean bottles four-fifths full, cork, and freeze in a tray; thaw gradually
till ball of ice one-eighth size of bottle remains. This contains
impurities to be reduced as III, below. Use rest for new bath at once.
II. _Hyposulphite Bath._
1. Precipitate as silver sulphide by potassium sulphide. Reduce as III,
below, or dissolve in nitric acid.
2. Precipitate by hydrosulphuric acid, and reduce as III.
3. Decompose hyposulphite by waste nitro-sulphuric acid from manufacture
of gun-cotton for collodion. Have silver sulphide and sulphur, with sodium
nitrate and sulphate in solution. Suspend zinc in solution, then boil two
or three hours; wash on filter, dry, fuse with borax and sodium carbonate.
4. Suspend sheet copper in bath.
5. Add hydrochloric acid, which sets free sulphur and precipitates silver
chloride. Oxidise sulphur by aqua regia, and reduce silver chloride as in
III.
6. Add sodium hypochlorite to the alkaline solution. Wash, precipitate,
and fuse with mixed carbonates. This gives sodium bisulphate and chloride
as by-products, no sulphur, no fumes.
III. _Reduction of Silver Chloride, Oxide, or
Sulphide._
1. Mix with one third weight of colophony. Heat moderately in crucible
till greenish-blue flame ceases, then suddenly increase heat, and obtain a
button of metal.
2. Melt with alkaline carbonates enough to cover surface from air; then
mix with 75 per cent. of chalk and 4 per cent. of charcoal, and heat.
3. Ignite with nitre on red-hot plate carefully, and in small quantities
to avoid explosion, run down to button with borax and sodic carbonate.
4. If chloride, reduce to oxide by boiling with strong potash, then reduce
by glucose; or boil the chloride with glucose and sodium carbonate.
5. Add silver chloride dissolved in ammonia to a boiling solution of one
part glucose and three parts sodium carbonate in 40 per cent. of water,
keeping up the boiling all the time.
6. Add to silver chloride sodium hydrate in solution and grape sugar, and
expose to sunlight in open dish with occasional stirring. Reduce to dark
brown oxide of silver, soluble in nitric acid.
7. Mix with five times weight of sodium carbonate. Fill hessian crucible
half full, and sprinkle sodium chloride over the top. Heat slowly in
anthracite fire. After half an hour increase heat till crucible is
white-hot. When complete fusion has taken place, allow to cool, and break
out button of silver.
8. Fuse with two parts mixed carbonates (sodium and potassium).
9. Add pure zinc and dilute sulphuric acid, and let stand two days. Wash
silver off with water acidulated with sulphuric acid, to remove all zinc;
finally fuse to a button.
10. Mix with half weight dry sodium carbonate and one-fourth weight of
clean dry sand, and ignite.
IV. _Gold Waste_, α, _Recovered_.
1. Make just acid with hydrochloric acid, add solution containing 2 oz.
pyrogallic acid, shake, let stand 24 hours; filter. Dissolve in aqua
regia, and product after evaporation will be found better for toning than
that precipitated by iron.
2. Acidify toning bath, and add sulphate of iron (2 grammes to 1 gramme
chloride of gold.)
β. _Separated from Silver._
1. Treat button obtained by fusing waste from hypo-toning and fixing baths
with dilute nitric acid. Wash insoluble part with ammonia to remove silver
chloride, if present, and dissolve in aqua regia.
2. Digest 20 grammes in flask with 1 fl. dr. hydrochloric acid, 15 m.m. of
nitric acid, and 2 dr. of water. After quarter of an hour boil, add 2 oz.
water; filter. Silver chloride with organic matter, &c. left undissolved.
Reduced as III, above.
3. Add excess of pure potassium hydrate, and then boil in flask with
excess of solid oxalic acid.
V. _Paper Waste._
1. Soak paper in strong solution of saltpetre, and burn.
2. Treat with nitric acid, precipitate with sodium chloride or potassium
hydrate, then put with III, above, for reduction.
_Washings from Positive Prints._
Precipitate by sodium chloride, potassium hydrate, or on copper plates,
&c., as above, and reduce, as in III.
VI. _Cyanide Solution._
1. Dilute with water, precipitate by (1) potassium sulphide, (2) sodium
chloride, and reduce as 3.
2. Decant bath into iron kettle, warm, add ferrous sulphate slowly till
slight precipitate of oxide. Make alkaline, and add solution of grape
sugar till brownish-yellow colour. Allow to settle, syphon off liquid.
Wash sediment on filter, and ignite to recover silver.
NOTE.——Ferrous sulphate forms ferrocyanide, therefore no free alkaline
cyanide should be present.
VII. _Developer._
1. _Vide_ II. (3, 4, 5, 6), with hypo bath; (1) and (2) not applicable,
for sulphide of iron would be formed.
2. Reduced by its own iron (if ferrous sulphate).
=PHOTOM′ETRY.= The art of determining the relative intensities of
different lights. Various methods have been adopted, at different times,
for this purpose, among which, however, a few only are sufficiently simple
for general application. The principle adopted by Bouguer and Lambert
depends on the fact that, though the eye cannot judge correctly of the
proportional force of different lights, it can generally distinguish with
great precision when two similar surfaces or objects presented together
are equally illuminated, or when the shadows of an opaque object produced
by different lights are equally dark. Now, as light travels in straight
lines, and is equally diffused, it is evident that its intensity will
progressively lessen as the distance of its source increases. This
diminution is found to be in the duplicate ratio of the distance. To apply
this principle to candles, lamps, gaslights, &c., we have only to arrange
two of them so that the light or shadow resulting from both shall be of
equal intensity, after which we must carefully measure the distance of
each of them from the surface on which the light or shadow falls. The
squares of these distances give their relative intensity. In general, some
known light, as that from a wax candle (4 to the lb.), is taken as the
standard of comparison.
Dr Ritchie’s ‘photometer’ consists of a rectangular box, about 2 inches
square, open at both ends, and blackened inside to absorb extraneous
light. In this, inclined at angles of 45° to its axis, are placed two
precisely similar rectangular plates of plain silvered glass, and fastened
so as to meet at the top, in the middle of a narrow slit about an inch
long and the eighth of an inch broad, and which is covered with a strip of
tissue or oiled paper. In employing this instrument, the “lights must be
placed at such a distance from each other, and from the instrument
between them, that the light from each shall fall on the reflector next
it, and be reflected to the corresponding portion of the oiled paper. The
photometer is then to be moved nearer to the one or the other, until the
two portions of the oiled paper corresponding to the two mirrors are
equally illuminated, of which the eye can judge with considerable
accuracy.”
In Prof Wheatstone’s ‘PHOTOMETER’ the relative intensity of the two lights
is determined by the relative brightness of the opposite sides of a
revolving silvered ball illuminated by them.
In the method of photometry usually, but erroneously, ascribed to Count
Rumford, the shadows of an opaque object formed by different lights, and
allowed to fall on a white wall or paper screen, are contrasted. A wire
about 3/16ths of an inch thick, and about a foot in length, with the one
end bent so as to form a handle, is commonly used to form the shadows. The
method of proceeding is similar to that first above noticed.
It is generally supposed that the equality of two shadows can be
appreciated with greater certainty than that of two lights.
=PHTHIS′IC.= A popular name for difficulty of breathing, from its supposed
resemblance to phthisis. See BRONCHITIS, and _below_.
=PHTHISIS.= (A wasting away.) This is the formidable disease ordinarily or
popularly known as “consumption,” although, strictly speaking, there are
points of difference between consumption and phthisis, as well as between
these and another variety of the malady known as tuberculosis. The
statistics which follow, however, apply to all those diseases of the lungs
accompanied by wasting, and as such include the mortality from phthisis,
tuberculosis, and consumption.
In the Registrar-General’s returns for many years past, under the heads
‘phthisis,’ or ‘tubercular disease,’ have been included chronic
bronchitis, emphysema, fibroid changes of the lungs and kindred
affections. ‘It is, however, probable that the figures representing the
mortality are fairly accurate, as the errors are to a certain extent
compensating; and, indeed, tubercles are often found even in the diseases
above mentioned.’[99]
[Footnote 99: Dr Wynter Blyth.]
The following table, taken from the Registrar-General’s returns for
1848-75, shows the annual number of deaths in England from phthisis,
during a period of 28 years:——
1848 51,663
1849 50,299
1850 46,618
1851 49,166
1852 50,594
1853 54,918
1854 51,284
1855 52,290
1856 48,950
1857 50,106
1858 50,442
1859 50,149
1860 51,024
1861 51,930
1862 50,962
1863 51,072
1864 53,046
1865 53,734
1866 55,714
1867 55,042
1868 51,423
1869 52,270
1870 54,231
1871 53,376
1872 52,589
1873 51,355
1874 49,379
1875 52,943
Dr Farr in his letter to the Registrar-General on the causes of death in
England in 1875, writes, “Phthisis is a most fatal disease, although it
has declined within the last twenty-five years.”
According to the same authority, the mean rate of mortality from this
disease was 2·811 per 1000 in the five years from 1850 to 1854, and 2·283
in the five years from 1870 to 1874.
One of the most prominent facts revealed even by a cursory study of the
statistics of phthisis, is the large share which the breathing of impure
or tainted air has in the origin and dissemination of the disease.
Hence it follows that thickly populated and overcrowded localities suffer
much more from its ravages than those which are less densely inhabited.
This is exemplified in the following table:——
-----------+-------+---------+-------------------------------------------
| | |Proximity| Average Annual Mortality |
| | | or | to 100,000 living. |
| |Density|nearness +--------------------+---------------------+
| | of |of Person| | Other diseases |
| |Persons| to | Phthisis. | of the |
| | to a | Person. | | Respiratory Organs.|
| | Sq. +---------+------+------+------+------+------+-------+
| | Mile. | |15 |25 |35 |15 |25 |35 |
| | | Yards. | to | to | to | to | to | to |
| | | | 25| 35| 45| 25| 35| 45 |
+----------+-------+---------+------+------+------+------+------+-------|
|Healthy | | | | | | | | |
| districts| 135 | 163 | 336 | 398 | 330 | 34 | 45 | 67 |
|London |19,470 | 14 | 264 | 395 | 493 | 45 | 69 | 148 |
|Lancashire| 1,008 | 60 | 419 | 475 | 484 | 46 | 86 | 195 |
|England | | | | | | | | |
| and Wales| 308 | 108 | 362 | 438 | 407 | 38 | 61 | 113 |
-----------+-------+---------+------+------+------+------+------+--------
In the very badly ventilated Leopoldstadt, in Vienna, 378 prisoners out of
4280 died between the years 1834 to 1847, or at the rate of 86 per 1000;
and out of these as many as 220, or 51·4 per 1000, died from phthisis.
Contrasting with this the rate of mortality from the same disease in the
well-ventilated House of Correction in the same city, we learn that out of
3037 there died in five years (from 1850-1854) 43, or 14 per 1000, and of
these 24, or only 7·9 per 1000, died from the same disease.
The great prevalence of phthisis that used to prevail, not only in our
army, but in the principal European ones, has been clearly shown to have
been referable to the overcrowding and defective ventilation of the
barracks. And this applied equally to the barracks of military stations
possessing such mild and genial climates as Gibraltar, Malta, Ionia,
Jamaica, Trinidad, Bermuda, &c.[100]
[Footnote 100: Dr Parkes.]
The sanitary Commissioners appointed some years back to inquire into the
prevalence of consumption amongst our soldiers, came to the conclusion
that the foul atmosphere of the barracks was the cause of it. The
correctness of our decision has been corroborated by the greatly
diminished number of deaths which have followed the improved ventilation
in our barracks, recommended by the Commissioners. At the present time,
owing to those hygienic improvements, the mortality from phthisis is not
more than half what it was in our army prior to 1867. The same
satisfactory results have been obtained by the introduction into the
French barracks of similar sanitary improvements.
Animals are affected in precisely the same manner as human beings. Thus,
it is that phthisis attacks monkeys when shut up in badly ventilated
buildings, and cows confined in close sheds.
After these statements we shall be prepared to find that indoor trades and
occupations swell the bills of mortality from phthisis much more than
those carried on in the open air. That this is the case is shown by the
following table:——
_Deaths from Phthisis at Victoria Park Hospital,
showing the influence of Occupation._
+------------------------+-----------------------------------------------+-------+
| | AGES UNDER | |
| Cause of Death. +---+---+---+---+---+---+---+---+---+---+-------+Totals.|
| | | | | | | | | | | | Not | |
| |20.|25.|30.|35.|40.|45.|50.|55.|60.|65.|stated.| |
+------------------------+---+---+---+---+---+---+---+---+---+---+-------+-------+
| | | | | | | | | | | | | |
|Female lives | 45| 41| 25| 15| 12| 3| 1| 1|...|...| ... | 143 |
|Indoor occupation | 32| 31| 30| 24| 15| 9| 5|...|...|...| 4 | 150 |
| { Mixed occupation| 10| 7| 7| 5| 4| 3| 4|...|...|...| 1 | 41 |
|Males { Outdoor occup. | 9| 21| 21| 13| 12| 11| 8| 2| 1|...| 2 | 100 |
| +---+---+---+---+---+---+---+---+---+---+-------+-------+
| | 96|100| 83| 57| 43| 26| 18| 3| 1|...| 7 | 434 |
| +---+---+---+---+---+---+---+---+---+---+-------+-------+
| _The same reduced to | | | | | | | | | | | | |
| a per centage._ | | | | | | | | | | | | |
|Female lives | 32| 28| 18| 10| 8| 2| 1| 1|...|...| ... | 100 |
|Indoor occupation | 21| 21| 20| 16| 10| 7| 3|...|...|...| 2 | 100 |
| { Mixed occupation| 24| 17| 17| 12| 10| 7| 10|...|...|...| 3 | 100 |
|Males { Outdoor occup. | 9| 21| 21| 13| 12| 11| 8| 2| 1|...| 2 | 100 |
| +---+---+---+---+---+---+---+---+---+---+-------+-------+
| | 86| 87| 76| 51| 40| 27| 22| 3| 1|...| 7 | 400 |
+------------------------+---+---+---+---+---+---+---+---+---+---+-------+-------+
The influence of occupation in developing phthisis is forcibly illustrated
in the following table:——
+-----------------+--------------------------+--------------------------+
| | |Death-rate by Phthisis and|
| | | other Lung Diseases at |
| District. | Nature of principal | between 15 and 25 years |
| | Industry in the District.| of age, per 100,000 of |
| | | each class referred to. |
+-----------------+--------------------------+-------------+------------+
| | | Male. | Female. |
| | | | |
|Berkhampstead |}Extensive female {| 219 | 578 |
|Leighton Buzzard |} employment in {| 319 | 554 |
| |} straw-plaiting {| | |
| | | | |
|Newport Pagnell |}Extensive female {| 301 | 615 |
|Towcester |} employment in {| 239 | 577 |
| |} lace-making {| | |
| | | | |
| |{Extensive female (with }| | |
|Yeovil |{ some males) employment}| 280 | 409 |
| |{ in glove-making }| | |
| | | | |
|Leek |}Extensive employment {| 437 | 856 |
|Congleton |} (more female than {| 566 | 790 |
|Macclesfield |} male) in silk work {| 593 | 890 |
| | | | |
|Standard Northern| | | |
| District | Agriculture | 531 | 333 |
+-----------------+--------------------------+-------------+------------+
The above figures may be supplemented by the others, which show the
difference between the deaths from phthisis and other lung diseases
occurring amongst the agricultural and the manufacturing populations, and
are another illustration of the nature of the toiler’s occupation upon his
liability to consumption. Thus, for every 100 deaths by phthisis and other
lung diseases that take place amongst the men in various agricultural
districts of England between the ages of fifteen to fifty-five, there are
in Coventry 163 deaths; in Blackburn and Skipton, 167; in Congleton and
Bradford, 168; in Leek, 182; in Macclesfield, 184; in Bolton, 190; in
Nottingham, 192; in Rochdale, 193; in Derby, 198; in Salford and
Ashton-under-Lyne, 203; in Leeds, 218; in Preston, 220; and in Manchester,
263.[101]
[Footnote 101: Quoted by Dr Wynter Blyth.]
As bearing directly upon the above portion of our subject, we may quote
the sixth report of the medical officer of the Privy Council, who therein
states——“In proportion as the people of a district are attracted to any
collective indoor occupation, in such proportion, other things being
equal, the district death-rate by lung diseases will be increased.”
The much larger number of cases of lung disease amongst those who pursue
indoor callings than amongst others whose occupations are carried on out
of doors, arises principally from the defective ventilation of the
workshops or rooms in which the labour is carried on.
When indoor occupations are practised in large and efficiently ventilated
apartments, or existence is passed in healthy houses, as in the dwellings
of the rich and upper classes, who have also the additional advantages of
good food and warm clothing, the liability to phthisis becomes immensely
diminished.
The much greater immunity from the disease which the richer enjoy over the
poorer classes has been carefully pointed out by Dr Guy, who, writing on
this subject in the ‘Journal of the Statistical Society,’ says——“The ratio
of deaths from consumption follows the same order as the average age at
death, being lowest where the average age is highest, and the reverse.
Thus the average age at death of the class of gentlemen is 58·61, and the
ratio of deaths from consumption 1 to 2·60; while in the class of artisans
the average age is 48·06, and the proportion from consumption is 1 to
2·29.
+----------+-----+-----+-----+-----+-----+----+----+-----+-----+------+---------+---------+
| | | | | | | | | | | | |Number of|
| | | | | | | | | | | | | Deaths |
| | | | | | | | | | | | +----+----+
| | | | | | | | | | | | | | O |
| | | | | | | | | | | | | | t |
| | | | | | | | | | | | | | h |
| | | | | | | | | | | | | C | e |
| | | | | | | | | | | A | | o | r |
| | | | | | | | | | | v | | n | |
| | | | | | | | | | | e a | | s | D |
| | | | | | | | | | | r t | | u | i |
| | | | | | | | | | | a | | m | s |
| | | | | | | | | | | g D | | p | e |
| | 15 | 20 | 30 | 40 | 50 | 60 | 70 | | | e e | | t | a |
| | | | | | | | |Under|Under| a | Ratio. | i | s |
|Condition.| to | to | to | to | to | to | to | 30. | 40. | a t | | o | e |
| | | | | | | | | | | g h | | n | s |
| | 20. | 30. | 40. | 50. | 60. | 70.| 80.| | | e . | | . | . |
+----------+-----+-----+-----+-----+-----+----+----+-----+-----+------+---------+----+----+
|Gentlemen,| | | | | | | | | | | | | |
| &c. |10·84|18·67|27·11|19·27|15·06|6·03|3·01|29·51|56·62|39 |1 to 5·00| 166| 835|
|Tradesmen | 8·46|24·34|26·98|20·11|12·70|6·35|1·06|32·80|59·78|38 |1 to 2·60| 189| 491|
|Artisans | 7·25|23·69|26·24|22·79|13·34|6·26|0·43|30·94|57·18|38-1/2|1 to 2·29|2318|5308|
+----------+-----+-----+-----+-----+-----+----+----+-----+-----+------+---------+----+----+
“Again, the class of gentry presents a smaller proportional number of
deaths under thirty and forty than either of the other classes. It is also
worthy of observation that the per-centage proportion of deaths from
consumption under thirty and forty is higher in the class of tradesmen
than in that of the artisan and labourer, although the ratio of cases of
consumption is greater in the latter class. This is doubtless accounted
for by the fact already established, that the strong exertion which a
considerable portion of the labouring class employed within doors use in
their occupations, and the large number employed out of doors, has the
effect of retarding the effect of pulmonary consumption. The tradesman, it
will be seen, occupies the intermediate place between the indoor and
outdoor labourer——between the artisan using little exertion and the
artisan using much exertion.
... Another point attracts attention, viz. the great proportion of deaths
from consumption occurring in the class of gentry from fifteen to twenty
years of age. Does not this show that the liability to the disease is
greater in this class than in the two others, and does it not tend to
strengthen the position that the excess of the deaths from consumption in
the other classes is due to the unfavorable circumstances in which they
are placed?
“The ratio of deaths from consumption in the class of gentry, low as it
is, would have been still lower if the medical men, who are included in
it, were omitted. The number of cases of pulmonary consumption occurring
in members of that profession is very remarkable, and it is a subject of
regret with the author that they were not made a separate class.”
Much less clearly and satisfactorily established is the question as to
whether consumption is or is not contagious. The instances which have
occurred of its extensive and rapid spread in overcrowded barracks,
prisons, men-of-war, merchant vessels, large workshops, &c., not
unreasonably seem to lend weight to the opinion that the germs of the
disease might have been conveyed by the atmosphere charged with them from
an unhealthy to a healthy subject, on whom they might develop the malady.
“But,” as Dr Blyth writes, “it must be remembered that, in all crowded
localities, there is direct vitiation of air, and it is difficult to say
whether the foul air or actual contagion have most to do with the
propagation of the malady.” He adds “that consumption, under ordinary
conditions, is certainly not contagious; but, under special insanitary
influences, certain forms of consumption may be contagious, although it is
still a matter not proven.” Dr Guy bases his objection to the doctrine of
the generally contagious nature of consumption upon the fact of the small
fluctuations in the annual number of deaths caused by it.
The lowest rate of mortality for phthisis for a million of inhabitants in
London was, he states, for any one of the fifteen years from 1840 to 1854
inclusive, 2645, and the fluctuation was very slight. The figures in three
consecutive years were——1849, 2777; 1850, 2645; 1851, 2970. “If, then,” Dr
Guy says, “any one were to assert that this disease is contagious, which
is tantamount to saying that it may be epidemic, the figures I have quoted
would in themselves furnish an answer in the negative. They are suggestive
of a domestic disease, influenced, as is bronchitis, by the seasons and
the weather.”
The statistics before quoted as to the correlation between the prevalence
of consumption and unhealthy surroundings, lead to the belief, that before
this connection between the two was so well defined, cases of phthisis
were often erroneously referred to hereditary taint, when they may simply
have arisen from the patient having been environed with the same
unfavorable hygienic conditions as his parents; these unfavorable
conditions, including not only polluted air, but bad food, deficient
apparel, and want of exercise. Hence it is that most of the later
pathologists, without denying the existence of the transmitted form of the
disease, believe the hereditary influence has been greatly over
estimated.
“As regards the origin of tubercle,” writes Dr Douglas Powell, “opinions
are extremely various, and indeed irreconcileable; but the tendency of
modern research——the experiments of inoculation in animals, and the very
powerful advocacy of Prof. Niemeyer, is certainly to show that tubercles
is much more commonly a secondary disease than has until lately been
suspected——that people are, in fact, only exceptionally, if ever, born to
die of tuberculosis.
“A due appreciation of this doctrine, so different from that even now
accepted by many, is of almost national importance in giving encouragement
to those hygienic and other measures of prevention, the neglect of which
has too often been sanctioned by a foregone conclusion.
“It would I think be extremely injudicious to deny hereditary
predisposition to tubercles altogether. Moreover, when we come to the
question of hereditary predisposition to the forms of consumption which
originate in catarrhal pneumonia, it is freely admitted that the offspring
of consumptive parents have a tendency to this form of pulmonary phthisis,
that the scrofulous have a like tendency (Niemeyer), and that scrofulosis
is sometimes hereditary.”
As allied to this portion of the question may be mentioned the opinion of
some pathologist, that phthisis may be either caused or promoted by
habitual drunkenness; and that a drunkard may transmit it to his
offspring.
The proneness to consumption is greatly modified by sex and age, the
influences of which upon the disease are very defined and unmistakable.
Thus, women are more liable to its attacks than men, and young and middle
aged persons of both sexes than old ones.
“In Edinburgh the ratio of deaths from phthisis was found to decline from
·285 at twenty years to ·052 above sixty years; at Nottingham, from ·416
to ·017 in the same period of time; at Chester, from ·245 to ·054; at
Carlisle, from ·290 to ·097; and in Paris, according to Louis, from ·325
to ·042; while the general average decline was from ·285, or 28·5 per
cent., at twenty to thirty, to ·078, or 7·80 per cent., above 60.”[102]
[Footnote 102: Blyth.]
Amongst other conditions unfavorable to the consumptive patient, in
addition to the breathing of a polluted atmosphere, may be named
insufficiency of nourishing food and apparel, variable weather, and a damp
soil. This latter is particularly inimical to phthisical sufferers. Indeed
so closely is dampness of soil associated with the spread of phthisis,
that the disease has been conclusively shown to have diminished in
localities in proportion as these have been properly drained. Dr Andrews,
of Chicago, says that consumption is most prevalent near the sea, and
that it diminishes in proportion to the distance of the inland locality
from the ocean. A damp atmosphere also provokes the disease.
Phthisis seems to be a malady peculiar to temperate climates. As to the
influence of the season upon the disease, Dr Haviland says, “In England we
learn from the statistical returns that the spring is the most fatal to
consumptive patients, whether male or female, but with regard to the other
seasons there is considerable variability. For instance, suppose we take
the seasons of 1838 in the order of their fatality to males, they would
stand thus——spring, 1137; winter, 1048; summer, 968; autumn, 904. To
females——spring, 972; summer, 937; winter, 896; autumn, 825. Then again,
although the spring invariably takes the lead, the other seasons change
places with each other from year to year; and what is remarkable, this
inconsistency does not seem to be dependent upon the temperature, as we
shall presently see. In the returns for 1853, the following statistics in
deaths from consumption appear:——Winter, 1872; spring, 1971; summer, 1745;
autumn, 1914. The order of fatality in the years above quoted would
therefore be:——
1838.——_Males._
1. Spring. 2. Winter. 3. Summer. 4. Autumn.
1838.——_Females._
1. Spring. 2. Summer. 3. Winter. 4. Autumn.
1840.——_Total._
1. Spring. 2. Winter. 3. Summer. 4. Autumn.
1853.——_Total._
1. Spring. 2. Autumn. 3. Winter. 4. Summer.
“So far, therefore, as seasons are concerned, the above table proves that
spring, _i.e._ April, May, June, is the most inimical quarter to
phthisical patients, and probably Autumn——October, November, December, the
least so. In London at least, if not throughout England generally, the
spring is undoubtedly the most obnoxious to consumptive cases; and this
statement is in accordance with the experience of those physicians who
have opportunities of seeing the rise, progress, and end of many hundreds
of phthisical patients during the year. Dr Richard Quain observes that the
cold easterly wind of spring completes the work, which the winter had left
undone.”[103]
[Footnote 103: ‘Climate, Weather, and Disease,’ by Dr Haviland.]
That greater or less destruction of the lungs, which is characteristic of
pulmonary phthisis, originates in the presence in them of a diseased
growth, consisting of very minute masses or grains, which are sometimes
grey, and at others yellow or cheeselike in appearance.
These little bodies are either diffused uniformly through the substance of
the lungs, or are collected together in them in larger or smaller masses.
In the latter case, each little mass generally sets up in the surrounding
tissue of the lungs, inflammation and suppuration, which, although only
processes by which nature endeavours to expel the alien substance from the
lung, may, by constant repetition, cause the destruction of the greater
part of the respiratory organs.
=PHYLLOXERA VASTATRIX.= In 1866 M. Delorme, of Arles, in the South of
France, was the first to suggest that a peculiar disease which had
manifested itself the previous year amongst the vines growing in the
plateau of Pujaut on the west bank of the river Rhone, in the Department
of the Gard, was of a new and specific character.
Shortly afterwards a commission appointed by the Herault Agricultural
Society visited one of the infested localities, and one of its members, M.
Planchon, confirmed M. Delorme’s conjectures, by discovering the cause of
the vine malady. This he conclusively showed was due to the presence of a
peculiar and hitherto unknown description of _Aphis_, belonging to the
genus _Phylloxera_, which, as illustrative of its devastating qualities,
he named _P. vastatrix_.
A full-grown _Phylloxera vastatrix_ does not exceed more than the 33rd or
40th of an inch in length. Examined under a microscope, in addition to
short pointed legs, it is seen to be furnished with a proboscis nearly
half as long as its body. Upon examination this proboscis seems to be
composed of three tongues, of which the centre one is the longest, and
these are united at their base into a kind of flat, sharp-pointed blade,
which is the boring or puncturing apparatus, by the aid of which the
insect pierces into the roots, from which it sucks the juices that
constitutes its food. About half the proboscis or sucker is inserted into
the bark of the root, and the creature can not only attach itself to the
root by means of it, but can also turn on it, as on a pivot, when engaged
in the depredations.
[Illustration: Male Phylloxera; dot in circle showing natural size.]
These are continued from April to October, by which month the insect has
lost the yellow colour that distinguishes it in the summer months, and
assumed a copper brown shade.
From October to April the Phylloxera hybernate, or rather, such of them do
as have laid no eggs during the period of their active existence, for the
egg-laying females die, and young phylloxeræ only are preserved during the
winter months.
With the return of April they awake from their winter sleep, and
recommence their devastating career. They then increase rapidly in size
and begin to lay unimpregnated eggs, for there are at that time no males.
“These bring forth females which in their turn develop and lay
unimpregnated eggs, and the virginal reproduction continues for five or
six generations, the development increasing in rapidity with the heat, but
the prolificacy or the number of the eggs decreases.
“In July some of the individuals show little wing-pads at the sides, and
begin to issue from the ground and acquire wings. These winged individuals
become very numerous in August, and continue to appear in diminishing
numbers thereafter till the leaves have all fallen. They are all females
and carry in their abdomen from three to eight eggs of two sizes, the
larger ones about 2/100ths of an inch long and half as wide; the smaller
3/4th as long. These eggs are also unimpregnated and are laid by
preference on the under side of the more tender leaves, attached by one
end, amid the natural down. They increase somewhat in size, and give birth
in about ten days to the true sexual individuals, the larger producing
females, the smaller, males.
“Anomalous as it may seem these creatures are born perfect, though without
mouth, and with no other than the reproductive function.
[Illustration: True female Phylloxera; _a_, ventral view, showing obsolete
mouth and solitary egg, occupying nearly the entire body; _b_, dorsal
view; _c_, tarsus; _d_, contracted anal joints after the egg is laid; dot
in circle showing natural size.]
“A most remarkable fact, discovered by Babiani, is that some of the
females never acquire wings, but always remain on the roots, also produce
the few different sized eggs from which these true, mouthless males and
females hatch. The sexes pair soon after hatching, and the female is
delivered on the 3rd or 4th day of a solitary egg, and then perishes. This
egg is never laid on the leaf, but always on the wood, either under the
bark, or in sheltered situations above ground, or on the roots
underground. The young hatching from it is the normal agamous mother,
which, with increased vigour and fertility, lays a large number of eggs,
and recommences the virginal reproduction and the cycle of the species’
curious life. The impregnated eggs laid early in the season doubtless
hatch the same year, though some of the later deposited ones may pass the
winter before hatching.”[104]
[Footnote 104: Riley.]
The parts of the vine attacked by the Phylloxera are the rootlets, which
in a diseased plant, may be seen more or less covered with what appears to
the naked eye, a yellowish powder, but upon a microscopic examination
reveals itself as a mixture of phylloxeræ of different sizes, and of their
eggs.
During August and September, the phylloxeræ invest the rootlets in
countless numbers, and are so abundant as to entirely obscure the colour
of the roots, and to cause them to appear yellow from the enormous number
of their minute organisms.
The effect of the attacks of the parasite upon the rootlets is to give
rise in it to the formation of a number of little tumefactions or
enlargements. These in course of time decay, and their destruction results
in the death of the plant.
Exposure to air and sunlight acts fatally to the Phylloxera, shrivelling
and drying it up. Hence its instinct of self-preservation, no less than
its search after its food, leads it to bury itself beneath the surface of
the soil. But, as the insect does not possess an organisation that fits it
for burrowing, the character of the soil has a great deal to do in
affording facilities or the reverse favorable to its existence.
If the soil be of such a nature, that it splits easily into fissures or
cracks, which better lead to or serve to expose the vine roots, it will of
course afford a much more easy means of access to the parasite than if it
be compact or close.
Hence it is that clayey and chalk soils, from their liability to split up
on the surface, afford much more congenial habitats for the Phylloxera
than sandy ones, which, being dry and closely-knit, afford a much more
impenetrable barrier to the entrance of the insect, or to its subterranean
movements.
[Illustration: _a_, healthy root; _b_, root on which the lice are working,
showing the knots and swellings caused by their punctures; _c_, root
deserted by them, on which the rootlets have begun to decay; _d_, _d_,
_d_, lice on the larger roots, natural size; _e_, female pupa, dorsal
view; _f_, winged female, dorsal view, greatly enlarged.]