PACKFONG, is the Chinese name of the alloy called white copper, or
German silver.
PACO, or PACOS, is the Peruvian name of an earthy-looking ore, which
consists of brown oxide of iron, with imperceptible particles of native
silver disseminated through it.
[Illustration: 774]
PADDING MACHINE (_Machine à plaquer_, Fr.; _Klatsch_, or
_Grundirmaschine_, Germ.); in calico-printing, is the apparatus for
imbuing a piece of cotton cloth uniformly with any mordant. In _fig._
774. A B C D represents in section a cast-iron frame, supporting two
opposite standards above M, in whose vertical slot the gudgeons _a b_,
of two copper or bronze cylinders E F, run; the gudgeons of E turn upon
fixed brasses or plummer blocks; but the superior cylinder F rests upon
the surface of the under one, and may be pressed down upon it with
greater or less force by means of the weighted lever _d e f g_, whose
centre of motion is at _d_, and which bears down upon the axle of F. K
is the roller upon which the pieces of cotton cloth intended to be
padded are wound; several of them, being stitched endwise together. They
receive tension from the action of a weighted belt _o_, _n_, which
passes round a pulley _n_ upon the end of the roller K. The trough G,
which contains the colouring matter or mordant, rests beneath the
cylinder upon the table L, or other convenient support. About two inches
above the bottom of the trough, there is a copper dip-roller C, under
which the cloth passes, after going round the guide roller _m_. Upon
escaping from the trough, it is drawn over the half-round stretcher-bar
at I, grooved obliquely right and left, as shown at N, whereby it
acquires a diverging extension from the middle, and enters with a smooth
surface between the two cylinders E F. These are lapped round 6 or 7
times with cotton cloth, to soften and equalize their pressure. The
piece of goods glides obliquely upwards, in contact with one third of
the cylinder F, and is finally wound about the uppermost roller H. The
gudgeon of H revolves in the end of the radius _h_, _k_, which is
jointed at _k_, and movable by a mortise at _i_ along the quadrantal arc
towards _l_, as the roller K becomes enlarged by the convolutions of the
web. The under cylinder E receives motion by a pulley or rigger upon its
opposite end, from a band connected with the driving-shaft of the
printshop. To ensure perfect equability in the application of the
mordant, the goods are in some works passed twice through the trough;
the pressure being increased the second time by sliding the weight _g_
to the end of the lever _d f_.
A view of a padding machine in connexion with the driving mechanism is
given under HOT FLUE; see also STARCHING MACHINE.
PAINT. See ROUGE.
PAINTS, GRINDING OF. There are many pigments, such as common orpiment,
or king’s yellow, and verdigris, which are strong poisons; others which
are very deleterious, and occasion dreadful maladies, such as white
lead, red lead, chrome yellow, and vermillion; none of which can be
safely ground by hand with the slab and muller, but should always be
triturated in a mill. The emanations of white lead cause, first, that
dangerous disease the _colica pictonum_, afterwards paralysis, or
premature decrepitude and lingering death.
[Illustration: 775 776 777 778]
_Figs._ 775, 776, 777, 778. exhibit the construction of a good
colour-mill in three views; _fig._ 775. being an elevation shown upon
the side of the handle, or where the power is applied to the shaft;
_fig._ 776. a second elevation, taken upon the side of the line _c_,
_d_, of the plan or bird’s-eye view, _fig._ 777.
The frame-work A A of the mill is made of wood or cast iron, strongly
mortised or bolted together; and strengthened by the two cross iron bars
B, B. _Fig._ 778. is a plan of the millstones. The lying or nether
millstone C, _fig._ 776, is of cast iron, and is channelled on its upper
face like corn millstones. It is fixed upon the two iron bars B, B; but
may be preferably supported upon the 3 points of adjustable screws,
passing up through bearing-bars. The millstone C is surrounded by a
large iron hoop D, for preventing the pasty-consistenced colour from
running over the edge. It can escape only by the sluice hole E, _fig._
776., formed in the hoop; and is then received in the tub X placed
beneath.
The upper or moving millstone F, is also made of cast iron. The dotted
lines indicate its shape. In the centre it has an aperture with ledges
G, G; there is also a ledge upon its outer circumference, sufficiently
high to confine the colour which may occasionally accumulate upon its
surface. An upright iron shaft H passes into the turning stone, and
gives motion to it. A horizontal iron bevel wheel K, _figs._ 776, 777.,
furnished with 27 wooden teeth, is fixed upon the upper end of the
upright shaft H. A similar bevel wheel L, having the same number of
teeth, is placed vertically upon the horizontal iron axis M, M, and
works into the wheel K. This horizontal axis M, M bears, at one of its
ends, a handle or winch N, by which the workman may turn the millstone
F; and on the other end of the same axis, the fly-wheel O is made fast,
which serves to regulate the movements of the machine. Upon one of the
spokes of the fly-wheel there is fixed, in like manner, a handle P,
which may serve upon occasion for turning the mill. This handle may be
attached at any convenient distance from the centre, by means of the
slot and screw-nut J.
The colour to be ground is put into the hopper R, below which the bucket
S is suspended, for supplying the colour uniformly through the orifice
in the millstone G. A cord or chain T, by means of which the bucket S is
suspended at a proper height for pouring out the requisite quantity of
colour between the stones, pulls the bucket obliquely, and makes its
beak rest against the square upright shaft H. By this means the bucket
is continually agitated in such a way as to discharge more or less
colour, according to its degree of inclination. The copper cistern X,
receives the colour successively as it is ground; and, when full, it may
be carried away by the two handles Z, Z; it may be emptied by the
stopcock Y, without removing the tub.
PAINTS, VITRIFIABLE. See PORCELAIN, POTTERY, and STAINED GLASS.
PALLADIUM; a rare metal, possessed of valuable properties; was
discovered in 1803, by Dr. Wollaston, in native platinum. It constitutes
about 1 per cent. of the Columbian ore, and from 1/4 to 1 per cent. of
the Uralian ore of this metal; occurring nearly pure in loose grains, of
a steel-gray colour, passing into silver white, and of a specific
gravity of from 11·8 to 12·14; also as an alloy with gold in Brazil, and
combined with selenium in the Harz near Tilkerode. Into the
nitro-muriatic solution of native platinum, if a solution of cyanide of
mercury be poured, the pale yellow cyanide of palladium will be thrown
down, which being ignited affords the metal. This is the ingenious
process of Dr. Wollaston. The palladium present in the Brazilian gold
ore may be readily separated as follows: melt the ore along with 2 or 3
parts of silver, granulate the alloy, and digest it with heat in nitric
acid of specific gravity 1·3. The solution containing the silver and
palladium, for the gold does not dissolve, being treated with common
salt or muriatic acid, will part with all its silver in the form of a
chloride. The supernatant liquor being concentrated and neutralized with
ammonia, will yield a rose-coloured salt in long silky crystals, the
ammonia-muriate of palladium, which being washed in ice-cold water, and
ignited, will afford 40 per cent. of metal.
The metal obtained by this process is purer than that by the former; and
if it be fused in a crucible along with borax, by the heat of a powerful
air-furnace or forge, a button of malleable and ductile palladium will
be produced. When a slip of it is heated to redness, it takes a
bronze-blue shade of greater or less intensity, as the slip is cooled
more or less slowly; but if it be suddenly chilled, as by plunging it
into water, it resumes instantly its white lustre. This curious
phenomenon depending upon oxidizement and de-oxidizement, in different
circumstances, serves at once to distinguish palladium from platinum.
Pure palladium resembles platinum, but has more of a silver hue; when
planished by the hammer into a cup, such as that of M. Bréant, in the
museum of the Mint at Paris, it is a splendid steel-white metal, not
liable, like silver, to tarnish in the air. Another cup made by M.
Bréant, weighing 2 lbs. (1 kilogramme), was purchased by Charles X., and
is now in the _garde-meuble_ of the French crown. The specific gravity
of this metal, when laminated, is stated by Dr. Wollaston at 11·8, and
by Vauquelin at 12·1. It melts at from 150° to 160° Wedgewood; and does
not oxidize at a white heat. When a drop of tincture of iodine, is let
fall upon the surface of this metal, and dissipated over a lamp flame, a
black spot remains, which does not happen with platinum. A slip of
palladium has been used with advantage to inlay the limbs of
astronomical instruments, where the fine graduated lines are cut,
because it is bright, and not liable to alteration, like silver.
There are a protoxide and peroxide of palladium. The proto-chloride
consists of 60 of metal and 40 of chlorine; the cyanide, of 67 of metal,
and 33 of cyanogen.
PALM OIL (_Huile de palme_, Fr.; _Palmöl_, Germ.); is obtained, in
Guinea and Guyana, by expressing, as also by boiling, the fruit of the
_avoira elais_. It has an orange colour, a smell of violets, a bland
taste, is lighter than water, melts at 84° Fahr., becomes rancid and
pale by exposure to air, dissolves in boiling alcohol, and consists of
69 parts of oleine, and 31 of stearine, in 100. It is employed chiefly
for making yellow soap. It may be bleached by the action of either
chlorine or oxygen gas, as also by that of light and heat.
_Palm oil, quantity of,_
+-------+---------+------------+---------+
| | |Retained for| |
| |Imported.|consumption.|Exported.|
+-------+---------+------------+---------+
|_Year._| _Cwts._ | _Cwts._ | _Cwts._ |
| 1835. | 260,151 | 242,733 | 30,915 |
| 1836. | 277,017 | 234,357 | 34,379 |
| 1837. | 223,329 | 214,000 | |
+-------+---------+------------+---------+
Duty, 1_s._ 3_d._ per cwt.
PAPER CUTTING. Mr. T. B. Crompton, of Farnworth, Lancashire, who
obtained a patent in May, 1821, for proposing to conduct the newly
formed web of paper in the Fourdrinier machine over heated cylinders,
for the purpose of drying it expeditiously, in imitation of the mode so
long practised in drying calicoes, obtained, along with Enoch Miller,
another, in May, 1828, for cutting the endless web of paper lengthwise,
by revolving circular blades, fixed upon a roller, parallel to a
cylinder, round which the paper is lapped, and progressively unwound.
A patent had been obtained two months before, for certain improvements
in cutting paper, by Mr. Edward Cowper, consisting of a machine, with a
reel on which the web of paper of very considerable length has been
previously wound, in the act of being made in a Fourdrinier’s machine;
this web of paper being of sufficient width to produce two, three, or
more sheets, when cut.
The several operative parts of the machine are mounted upon standards,
or frame-work, of any convenient form or dimensions, and consist: of
travelling endless tapes to conduct the paper over and under a series of
guide rollers; of circular rotatory cutters for the purpose of
separating the web of paper into strips equal to the widths of the
intended sheets; and of a saw-edged knife, which is made to slide
horizontally for the purpose of separating the strips into such portions
or lengths as shall bring them to the dimensions of a sheet of paper.
[Illustration: 779]
The end of the web of paper from the reel _a_, _fig._ 779. is first
conducted up an inclined plane _b_ by hand; it is then taken hold of by
endless tapes extended upon rollers, as in Mr. Cowper’s PRINTING
MACHINE, which see. These endless tapes carry the web of paper to the
roller _c_, which is pressed against the roller _d_ by weighted levers,
acting upon the plummer blocks that its axle is mounted in. The second
roller _d_ may be either of wood or metal, having several grooves formed
round its periphery for the purpose of receiving the edges of the
circular cutters _e_, (see CARD-CUTTING) mounted upon an axle turning
upon bearings in the standards or frame.
In order to allow the web of paper to proceed smoothly between the two
rollers _c_, _d_, a narrow rib of leather is placed round the edges of
one or both of these rollers, for the purpose of leaving a free space
between them, through which the paper may pass without wrinkling.
From the first roller _c_, the endless tapes conduct the paper over the
second _d_, and then under a pressing roller _f_, in which progress the
edges of the circular knives _e_, revolving in the grooves of the second
roller _d_, cut the web of paper longitudinally into strips of such
widths as may be required, according to the number of the circular
cutters and distances between them.
The strips of paper proceed onward from between the knife roller _d_ and
pressing roller _f_, conducted by tapes, until they reach a fourth
roller _g_, when they are allowed to descend, and to pass through the
apparatus designed to cut them transversely; that is, into sheet
lengths.
The apparatus for cutting the strips into sheets is a sliding knife,
placed horizontally upon a frame at _h_, which frame, with the knife
_e_, is moved to and fro by a jointed rod _i_, connected to a crank on
the axle of the pulley _k_. A flat board or plate _l_ is fixed to the
standard frame in an upright position, across the entire width of the
machine; and this board or plate has a groove or opening cut along it
opposite to the edge of the knife. The paper descending from the fourth
roller _g_ passes against the face of this board, and as the carriage
with the knife advances, two small blocks, mounted upon rods with
springs _m m_, come against the paper, and hold it tight to the board or
plate _l_, while the edge of the knife is protruded forward into the
groove of that board or plate, and its sharp saw-shaped teeth passing
through the paper, cut one row of sheets from the descending strips;
which, on the withdrawing of the blocks, falls down, and is collected on
the heap below.
The power for actuating this machine is applied to the reverse end of
the axle, on which the pulley _k_ is fixed, and a band _n_, _n_, _n_,
_n_, passing from this pulley over tension wheels _o_, drives the wheel
_q_ fixed to the axle of the knife roller _d_; hence this roller
receives the rotatory motion which causes it to conduct forward the web
of paper, but the other rollers _c_ and _f_, are impelled solely by the
friction of contact.
The rotation of the crank on the axle of _k_, through the intervention
of the crank-rod _i_, moves the carriage _h_, with the knife, to and fro
at certain periods, and when the spring blocks _m_ come against the
grooved plate _l_, they slide their guide rods into them, while the
knife advances to sever the sheets of paper. But as sheets of different
dimensions are occasionally required, the lengths of the slips delivered
between each return of the knife are to be regulated by enlarging or
diminishing the diameter of the pulley _k_, which will of course retard
or facilitate the rotation of the three conducting rollers, _c_, _d_,
_f_, and cause a greater or less length of the paper to descend between
each movement of the knife carriage.
The groove of this pulley _k_, which is susceptible of enlargement, is
constructed of wedge-formed blocks passed through its sides, and meeting
each other in opposite directions, so that on drawing out the wedges a
short distance, the diameter of the pulley becomes diminished; or by
pushing the wedges further in, the diameter is increased; and a tension
wheel _p_ being suspended in a weighted frame, keeps the band always
tight.
As it is necessary that the paper should not continue descending while
it is held by the blocks _m_, _m_ to be cut, and yet that it should be
led on progressively over the knife roller _d_, the fourth roller _g_,
which hangs in a lever _j_, is made to rise at that time, so as to take
up the length of paper delivered, and to descend again when the paper is
withdrawn. This is effected by a rod _r_, connected to the crank on the
shaft of the aforesaid roller _k_, and also to the under part of the
lever _j_, which lever hanging loosely upon the axle of the knife roller
_d_, as its fulcrum, vibrates with the under roller _g_, so as to effect
the object in the way described.
The patentee states that several individual parts of this machine are
not new, and that some of them are to be found included in the
specifications of other persons, such as the circular cutters _e_, which
are employed by Mr. Dickinson (CARD-CUTTING), and the horizontal cutter
_h_, by Mr. Hansard; he therefore claims only the general arrangement of
the parts in the form of a machine for the purpose of cutting paper, as
the subject of his invention.
[Illustration: 780]
The machine for cutting paper contrived by John Dickinson, Esq. of Nash
Mill, was patented in January, 1829. The paper is wound upon a
cylindrical roller _a_, _fig._ 780., mounted upon an axle, supported in
an iron frame or standard. From this roller the paper in its breadth is
extended over a conducting drum _b_, also mounted upon an axle turning
in the frame or standard, and after passing under a small guide roller,
it proceeds through a pair of drawing or feeding rollers _c_, which
carry it into the cutting machine.
Upon a table _d_, _d_, firmly fixed to the floor of the building, there
is a series of chisel-edged knives _e_, _e_, _e_, placed at such
distances apart as the dimensions of the cut sheets of paper are
intended to be. These knives are made fast to the table, and against
them a series of circular cutters _f_, _f_, _f_, mounted in a swinging
frame _g_, _g_, are intended to act. The length of paper being brought
along the table over the edges of the knives, up to a stop _h_, the
cutters are then swung forwards, and by passing over the paper against
the stationary knives, the length of paper becomes cut into three
separate sheets.
The frame _g_, _g_, which carries the circular cutters _f_, _f_, _f_,
hangs upon a very elevated axle, in order that its pendulous swing may
move the cutters as nearly in a horizontal line as possible; and it is
made to vibrate to and fro by an eccentric, or crank, fixed upon a
horizontal rotatory shaft extending over the drum _b_, considerably
above it, which may be driven by any convenient machinery.
The workmen draw the paper from between the rollers _c_, and bring it up
to the stop _h_, in the intervals between the passing to and fro of the
swing-cutters.
The following very ingenious apparatus for cutting the paper web
transversely into any desired lengths, was made the subject of a patent
by Mr. E. N. Fourdrinier, in June, 1831, and has since been performing
its duty well in many establishments.
[Illustration: 781 782]
_Fig._ 781. is an elevation, taken upon one side of the machine; and
_fig._ 782. is a longitudinal section. _a_, _a_, _a_, _a_, are four
reels, each covered with one continuous sheet of paper; which reels are
supported upon bearings in the frame-work _b_, _b_, _b_. _c_, _c_, _c_,
is an endless web of felt-cloth passed over the rollers _d_, _d_, _d_,
_d_, which is kept in close contact with the under side of the drum _e_,
_e_, seen best in _fig._ 782.
The several parallel layers of paper to be cut, being passed between the
drum _e_, and the endless felt _c_, will be drawn off their respective
reels, and fed into the machine, whenever the driving-band is slid from
the loose to the fast pulley upon the end of the main shaft _f_. But
since the progressive advance of the paper-webs must be arrested during
the time of making the cross cut through it, the following apparatus
becomes necessary. A disc _g_, which carries the pin or stud of a crank
_i_, is made fast to the end of the driving shaft _f_. This pin is set
in an adjustable sliding piece, which may be confined by a screw within
the bevelled graduated groove, upon the face of the disc _g_, at
variable distances from the axis, whereby the eccentricity of the stud
_i_, and of course the throw of the crank, may be considerably varied.
The crank stud _i_ is connected by its rod _j_, to the swinging
curvilinear rack _k_, which takes into the toothed wheel _l_, that turns
freely upon the axle of the feed drum _e_, _e_. From that wheel the arms
_m_, _m_, rise, and bear one or more palls _n_, which work in the teeth
of the great ratchet wheel _o_, _o_, mounted upon the shaft of the drum
_e_.
[Illustration: 783]
The crank-plate _g_ being driven round in the direction of its arrow,
will communicate a see-saw movement to the toothed arc _k_, next to the
toothed wheel _l_ in gearing with it, and an oscillatory motion to the
arms _m_, _m_, as also to their surmounting pall _n_. In its swing to
the left hand, the catch of the pall will slide over the slope of the
teeth of the ratchet wheel _o_; but in its return to the right hand, it
will lay hold of these teeth, and pull them, with their attached drum,
round a part of a revolution. The layers of paper in close contact with
the under half of the drum will be thus drawn forward at intervals, from
the reels, by the friction between its surface and the endless felt, and
in lengths corresponding to the arc of vibration of the pall. The knife
for cutting these lengths transversely is brought into action at the
time when the swing arc is making its inactive stroke, viz., when it is
sliding to the left over the slopes of the ratchet teeth _o_. The extent
of this vibration varies according to the distance of the crank stud
_i_, from the centre _f_, of the plate _g_, because that distance
regulates the extent of the oscillations of the curvilinear rack, and
that of the rotation of the drum _e_, by which the paper is fed forwards
to the knife apparatus. The proper length of its several layers being by
the above described mechanism carried forward over the bed _r_ of the
cutting knife or shears _r_, _v_, whose under blade _r_ is fixed, the
wiper _s_, in its revolution with the shaft _f_, lifts the tail of the
lever _t_, consequently depresses the transverse movable blade _v_ (as
shown in _fig._ 783.), and slides the slanting blades across each other
obliquely, like a pair of scissors, so as to cause a clean cut across
the plies of paper. But just before the shears begin to operate, the
transverse board _u_ descends to press the paper with its edge, and hold
it fast upon the bed _r_. During the action of the upper blade _v_,
against the under _r_, the fall board _u_, is suspended by a cord
passing across pullies from the arm _y_ of the bell-crank lever _t_,
_t_. Whenever the lifter cam _s_, has passed away from the tail of the
bell-crank _t_, the weight _z_, hung upon it, will cause the blade _v_,
and the pinching board _u_, to be moved up out of the way of the next
length of paper, which is regularly brought forward by the rotation of
the drum _e_, as above described. The upper blade of the shears is not
set parallel to the shaft of the drum, but obliquely to it, and is,
moreover, somewhat curved, so as to close its edge progressively upon
that of the fixed blade. The blade _v_ may also be set between two guide
pieces, and have the necessary motion given to it by levers.
PAPER-HANGINGS, called more properly by the French, _papiers peints_.
The art of making paper-hangings, _papier de tenture_, has been copied
from the Chinese, among whom it has been practised from time immemorial.
The English first imported and began to imitate the Chinese
paper-hangings; but being exposed till very lately to a high excise duty
upon the manufacture, they have not carried it to that extent and pitch
of refinement which the French genius has been enabled to do, unchecked
by taxation. The first method of making this paper was stencilling; by
laying upon it, in an extended state, a piece of pasteboard having
spaces cut out of various figured devices, and applying different water
colours with the brush. Another piece of pasteboard with other patterns
cut out was next applied, when the former figures were dry, and new
designs were thus imparted. By a series of such operations, a tolerable
pattern was executed, but with no little labour and expense. The
processes of the calico printer were next resorted to, in which engraved
blocks of the pear or sycamore were employed to impress the coloured
designs.
Paper-hangings may be distinguished into two classes; 1. those which are
really painted, and which are designed in France under the title of
_papiers peints_, with brilliant flowers and figures; and 2. those in
which the designs are formed by foreign matters applied to the paper,
under the name of _papier tontisse_, or flock paper.
The operations common to paper-hangings, of both kinds, may be stated as
follows:--