PHOSPHORUS. This interesting simple combustible, being an object of
extensive consumption, and therefore of a considerable chemical
manufacture, I shall describe the requisite manipulations for preparing
it at some detail. Put 1 cwt. of finely ground bone-ash, such as is used
by the assayers, into a stout tub, and let one person work it into a
thin pap with twice its weight of water, and let him continue to stir it
constantly with a wooden bar, while another person pours into it, in a
uniform but very slender stream, 78 pounds of concentrated sulphuric
acid.
The heat thus excited in the dilution of the acid, and in its reaction
upon the calcareous base, is favourable to the decomposition of the bone
phosphate. Should the resulting sulphate of lime become lumpy, it must
be reduced into a uniform paste, by the addition of a little water from
time to time. This mixture must be made out of doors, as under an open
shed, on account of the carbonic acid and other offensive gases which
are extricated. At the end of 24 hours, the pap maybe thinned with water
and, if convenient, heated, with careful stirring, to complete the
chemical change, in a square pan made of sheet lead, simply folded up at
the sides. Whenever the paste has lost its granular character, it is
ready for transfer into a series of tall casks, to be further diluted
and settled, whereby the clear superphosphate of lime may be run off by
a syphon from the deposit of gypsum. More water must then be mixed with
the precipitate, after subsidence of which, the supernatant liquor is
again to be drawn off. The skilful operator employs the weak acid from
one cask to wash the deposit in another, and thereby saves fuel in
evaporation.
The collected liquors being put into a leaden, or preferably a copper
pan, of proper dimensions, are to be concentrated by steady ebullition,
till the calcareous deposit becomes considerable; after the whole has
been allowed to cool, the clear liquor is to be run off, the sediment
removed, and thrown on a filter. The evaporation of the clear liquor is
to be urged till it acquires the consistence of honey. Being now
weighed, it should amount to 37 pounds. One fourth of its weight of
charcoal in fine powder, that is, about 9 pounds, are then to be
incorporated with it, and the mixture is to be evaporated to dryness in
a cast-iron pot. A good deal of sulphurous acid is disengaged along with
the steam at first, from the reaction of the sulphuric acid upon the
charcoal, and afterwards some sulphuretted hydrogen. When the mixture
has become perfectly dry, as shown by the redness of the bottom of the
pot, it is to be allowed to cool, and packed tight into stoneware jars
fitted with close covers, till it is to be subjected to distillation.
For this purpose, earthen retorts of the best quality, and free from
air-holes, must be taken, and evenly luted over their surface with a
compost of fire-clay and horse-dung. When the coating is dry and sound,
the retort is to be two-thirds filled with the powder, and placed upon
proper supports in the laboratory of an air-furnace, having its fire
placed not immediately beneath the retort, but to one side, after the
plan of a reverberatory; whereby the flame may play uniformly round the
retort, and the fuel may be supplied as it is wanted, without admitting
cold air to endanger its cracking. The gallery furnace of the palatinate
(under MERCURY) will show how several retorts may be operated upon
together, with one fire.
To the beak of the retort properly inclined, the one end of a bent
copper tube is to be tightly luted, while the other end is plunged not
more than one quarter of an inch beneath the surface of water contained
in a small copper or tin trough placed beneath, close to the side of the
furnace, or in a wide-mouthed bottle. It is of advantage to let the
water be somewhat warm, in order to prevent the concretion of the
phosphorus in the copper tube, and the consequent obstruction of the
passage. Should the beak of the retort appear to get filled with solid
phosphorus, a bent rod of iron may be heated, and passed up the copper
tube, without removing its end from the water. 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 acid and sulphurous acid gases 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 2 bubbles per second. If the
discharge comes to be interrupted, 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. In fact, the great nicety in distilling phosphorus lies in
the management of the fire, which must be incessantly watched, and fed
by the successive introduction of fuel, consisting of coke with a
mixture of dry wood and coal.
We may infer that the process approaches its conclusion by the
increasing slowness with which 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, from condensation of its
gaseous contents, by admitting air into it through a recurved glass
tube, or through the lute of the copper adopter.
The usual period of the operation upon the great scale is from 24 to 30
hours. Its theory is very obvious. The charcoal at an elevated
temperature disoxygenates the phosphoric acid with the production of
carbonic acid gas at first, and afterwards carbonic oxide gas, along
with sulphuretted, carburetted, and phosphuretted hydrogen, from the
reaction of the water present in the charcoal upon the other
ingredients.
The phosphorus falls down in drops, like melted wax, and concretes at
the bottom of the water in the receiver. It requires to be purified by
squeezing in a shamoy leather bag, while immersed under the surface of
warm water, contained in an earthen pan. Each bag must be firmly tied
into a ball form, of the size of the fist, and compressed, under the
water heated to 130°, by a pair of flat wooden pincers, like those with
which oranges are squeezed.
The purified phosphorus is moulded for sale into little cylinders, by
melting it at the bottom of a deep jar filled with water, then plunging
the wider end of a slightly tapering but straight glass tube into the
water, sucking this up to the top of the glass, so as to warm it, next
immersing the end in the liquid phosphorus, and sucking it up to any
desired height.
The tube being now shut at bottom by the application of the point of the
left index, may be taken from the mouth and transferred into a pan of
cold water to congeal the phosphorus; which then will commonly fall out
of itself, if the tube be nicely tapered, or may at any rate be pushed
out with a stiff wire. Were the glass tube not duly warmed before
sucking up the phosphorus, this would be apt to congeal at the sides,
before the middle be filled, and thus form hollow cylinders, very
troublesome and even dangerous to the makers of phosphoric
match-bottles. The moulded sticks of phosphorus are finally to be cut
with scissors under water to the requisite lengths, and put up in phials
of a proper size; which should be filled up with water, closed with
ground stoppers, and kept in a dark place. For carriage to a distance,
each phial should be wrapped in paper, and fitted into a tin-plate case.
Phosphorus has a pale yellow colour, is nearly transparent, brittle when
cold, soft and pliable, like wax, at the temperature of 70° F.,
crystallizing in rhombo-dodecahedrons out of its combination with
sulphur, and of specific gravity 1·77. It exhales white fumes in the
air, which have a garlic smell, appear luminous in the dark, and
spontaneously condense into liquid phosphorous acid. Phosphorus melts in
close vessels, at 95°. F., into an oily-looking colourless fluid, begins
to evaporate at 217·5°, boils at 554°, and if poured in the liquid state
into ice-cold water, it becomes black, but resumes its former colour
when again melted and slowly cooled. It has an acrid disagreeable taste,
and acts deleteriously in the stomach, though it has been administered
as a medicine by some of the poison-doctors of the present day. It takes
fire in the open air at the temperature of 165°, but at a lower degree
if partially oxidized, and burns with great vehemence and splendour.
Inflammable match-boxes (_briquets phosphoriques_) are usually prepared
by putting into a small phial of glass or lead a bit of phosphorus, and
oxidizing it slightly by stirring it round with a redhot iron wire. The
phial should be unstoppered only at the instant of plunging into it the
tip of the sulphur match which we wish to kindle. Bendix has given the
following recipe for charging such match-phials. Take one part of fine
dry cork raspings, one part of yellow wax, eight parts of petroleum, and
four of phosphorus, incorporate them by fusion, and when the mixture has
concreted by cooling, it is capable of kindling a sulphur match dipped
into it. Phosphorus dissolves in fat oils, forming a solution luminous
in the dark at ordinary temperatures. A phial half filled with this oil,
being shaken and suddenly uncorked, will give light enough to see the
dial of a watch by night.
There are five combinations, of phosphorus and oxygen:--1. the white
oxide; 2. the red oxide; 3. hypophosphorous acid; 4. phosphorous acid;
5. phosphoric acid. The last is the only one of interest in the arts. It
may be obtained from the syrupy superphosphate of lime above described,
by diluting it with water, saturating with carbonate of ammonia;
evaporating, crystallizing, and gently igniting the salt in a retort.
The ammonia is volatilized, and may be condensed into water by a
Woulfe’s apparatus, while the phosphoric acid remains in the bottom of
the retort. Phosphoric acid may be more readily produced by burning
successive bits of phosphorus in a silver saucer, under a great bell jar
inverted upon a glass plate, so as to admit a little air to carry on the
combustion. The acid is obtained in a fine white snowy deposit;
consisting, in this its dry state, of 44 of phosphorus and 56 of oxygen.
That obtained from the syrupy solution is a hydrate, and contains 9·44
per cent. of water. If the atom of phosphorus be called 32 upon the
hydrogen radix, then 5 atoms of oxygen = 40 will be associated with it
in the dry acid, = 72; and an additional atom of water = 9, in the
hydrate, will make its prime equivalent 81. Phosphorous acid seems to
contain no more than 3 atoms of oxygen.
The only salts of this acid much in demand, are the phosphate of soda,
and the ammonia phosphate of soda. The former is prepared by slightly
supersaturating superphosphate of lime with crystals of carbonate of
soda; warming the solution, filtering, evaporating, and crystallizing.
It is an excellent purgative, and not unpalatable. The triple phosphate
is used in docimastic operations; and is described under METALLURGY.
PICAMARE, is a thick oil, one of the six new principles detected by M.
Reichenbach, in wood-tar. See CREOSOTE and PARAFFINE. Picamare
constitutes 1-6th of beech-tar.
PICROMEL, is the name given by M. Thenard to a black bitter principle
which he supposed to be peculiar to the bile. MM. Gmelin and Tiedemann
have since called its identity in question.
PICROTOXINE, is an intensely bitter poisonous vegetable principle,
extracted from the seeds of the _Menispermum cocculus_, (Cocculus
Indicus). It crystallizes in small white needles, or columns; dissolves
in water and alcohol. It does not combine with acids, but with some
bases, and is not therefore of an alkaline nature, as had been at first
supposed.
PIGMENTS, VITRIFIABLE, belong to five different styles of work: 1. to
enamel painting; 2. to painting on metals; 3. to painting on stoneware;
4. to painting on porcelain; 5. to stained glass.
PIMENTO; _Myrtus pimenta_, or Jamaica pepper; consists, according to
Bonastre’s complicated analysis, of:--
+--------------------------------+---------+--------+
| |Shells or|Kernels.|
| |Capsules.| |
+--------------------------------+---------+--------+
|Volatile oil | 10·0 | 5·0 |
|Soft green resin | 8·0 | 2·5 |
|Fatty concrete oil | 0·9 | 1·2 |
|Extract containing tannin | 11·4 | 39·8 |
|Gum | 3·0 | 7·2 |
|Brown matter dissolved in potash| 4·0 | 8·0 |
|Resinoid matter | 1·2 | 3·2 |
|Extract containing sugar | 3·0 | 8·0 |
|Gallic and malic acids | 0·6 | 1·6 |
|Vegetable fibre | 50·0 | 16·0 |
|Ashes charged with salts | 2·8 | 1·9 |
|Moisture and loss | 4·1 | 4·8 |
+--------------------------------+---------+--------+
Pimento imported for home consumption, in 1835. 1836.
Duty--British possessions, 5_d._; foreign,
1_s._ 3_d._ Lbs. 344,458. 400,914.
PINCHBECK, is a modification of brass; see that article and COPPER.
PINE-APPLE YARN and CLOTH. In Mr. Zincke’s process, patented in
December, 1836, for preparing the filaments of this plant, the _Bromelia
ananas_, the leaves being plucked, and deprived of the prickles round
their edges by a cutting instrument, are then beaten upon a wooden block
with a wooden mallet, till a silky-looking mass of fibres be obtained,
which are to be freed by washing from the green fecula. The fibrous part
must next be laid straight, and passed between wooden rollers. The
leaves should be gathered between the time of their full maturity and
the ripening of the fruit. If earlier or latter, the fibres will not be
so flexible, and will need to be cleared by a boil in soapy water for
some hours; after being laid straight under the pressure of a wooden
grating, to prevent their becoming entangled. When well washed and
dried, with occasional shaking out, they will now appear of a silky
fineness. They may be then spun into porous rovings, in which state they
are most conveniently bleached by the ordinary methods.
Specimens of cambric, both bleached and unbleached, woven with these
fibres, have been recently exhibited, which excited hopes of their
rivalling the finest flax fabrics, but in my opinion without good
reason, on account of their want of strength.
PINEY TALLOW, is a concrete fat obtained by boiling with water the fruit
of the _Vateria indica_, a tree common upon the Malabar coast. It seems
to be a substance intermediate between tallow and wax; partaking of the
nature of stearine. It melts at 97-1/2° F., is white or yellowish, has a
spec. grav. of 0·926; is saponified by alkalies, and forms excellent
candles. Dr. Benjamin Babington, to whom we are indebted for all our
knowledge of piney tallow, found its ultimate constituents to be, 77 of
carbon, 12·3 of hydrogen, and 10·7 of oxygen.
PIN MANUFACTURE. (_Fabrique d’épingles_, Fr.; _Nadelfabrik_, Germ.) A
pin is a small bit of wire, commonly brass, with a point at one end, and
a spherical head at the other. In making this little article, there are
no less than fourteen distinct operations.
1. _Straightening the wire._ The wire, as obtained from the
drawing-frame, is wound about a bobbin or barrel, about 6 inches
diameter, which gives it a curvature that must be removed. The
straightening engine is formed by fixing 6 or 7 nails upright in a
waving line on a board, so that the void space measured in a straight
line between the first three nails may have exactly the thickness of the
wire to be trimmed; and that the other nails may make the wire take a
certain curve line, which must vary with its thickness. The workman
pulls the wire with pincers through among these nails, to the length of
about 30 feet, at a running draught; and after he cuts that off, he
returns for as much more; he can thus finish 600 fathoms in the hour. He
next cuts these long pieces into lengths of 3 or 4 pins. A day’s work of
one man amounts to 18 or 20 thousand dozen of pin-lengths.
2. _Pointing_, is executed on two iron or steel grindstones, by two
workmen, one of whom roughens down, and the other finishes. Thirty or
forty of the pin wires are applied to the grindstone at once, arranged
in one plane, between the two forefingers and thumbs of both hands,
which dexterously give them a rotatory movement.
3. _Cutting these wires into pin-lengths._ This is done by an adjusted
chisel. The intermediate portions are handed over to the _pointer_.
4. _Twisting of the wire for the pin-heads._ These are made of a much
finer wire, coiled into a compact spiral, round a wire of the size of
the pins, by means of a small lathe constructed for the purpose.
5. _Cutting the heads._ Two turns are dexterously cut off for each head,
by a regulated chisel, A skilful workman may turn off 12,000 in the
hour.
6. _Annealing the heads._ They are put into an iron ladle, made redhot
over an open fire, and then thrown into cold water.
7. _Stamping or shaping the heads._ This is done by the blow of a small
ram, raised by means of a pedal lever and a cord. The pin-heads are also
fixed on by the same operative, who makes about 1500 pins in the hour,
or from 12,000 to 15,000 per diem; exclusive of one-thirteenth, which is
always deducted for waste in this department, as well as in the rest of
the manufacture. Cast heads, of an alloy of tin and antimony, were
introduced by patent, but never came into general use.
8. _Yellowing or cleaning the pins_, is effected by boiling them for
half an hour in sour beer, wine lees, or solution of tartar; after which
they are washed.
9. _Whitening or tinning._ A stratum of about 6 pounds of pins is laid
in a copper pan, then a stratum of about 7 or 8 pounds of grain tin; and
so alternately till the vessel be filled; a pipe being left inserted at
one side, to permit the introduction of water slowly at the bottom,
without deranging the contents. When the pipe is withdrawn, its space is
filled up with grain tin. The vessel being now set on the fire, and the
water becoming hot, its surface is sprinkled with 4 ounces of cream of
tartar; after which it is allowed to boil for an hour. The pins and tin
grains are, lastly, separated by a kind of cullender.