JACK, called also _jack in a box_, and _hand-jack_, is a portable,
mechanical instrument, consisting of a rack and pinion, or a pair of
claws and ratchet bar, moved by a winch handle, for raising heavy
weights a little way off the ground.
JACK and JACK-SINKERS, are parts of a stocking frame; see HOSIERY.
JACK-BACK, is the largest jack of the brewer.
JACQUARD. A peculiar and most ingenious mechanism, invented by M.
Jacquart of Lyons, to be adapted to a silk or muslin loom for
superseding the employment of draw-boys, in weaving figured goods.
Independently of the ordinary play of the warp threads for the formation
of the ground of such a web, all those threads which should rise
simultaneously to produce the figure, have their appropriate healds,
which a child formerly raised by means of cords, that grouped them
together into a system, in the order, and at the time desired by the
weaver. This plan evidently occasioned no little complication in the
machine, when the design was richly figured; but the apparatus of
Jacquart, which subjects this manœuvre to a regular mechanical
operation, and derives its motion from a simple pedal put in action by
the weaver’s feet, was generally adopted soon after its invention in
1800. Every common loom is susceptible of receiving this beautiful
appendage. It costs in France, 200 francs, or 8_l._ sterling; and a
little more in this country.
[Illustration: 566 567 568]
_Fig._ 566. is a front elevation of this mechanism, supposed to be let
down. _Fig._ 567. is a cross section, shown in its highest position.
_Fig._ 568. the same section as the preceding, but seen in its lower
position.
A, is the fixed part of the frame, supposed to form a part of the
ordinary loom; there are two uprights of wood, with two cross-bars
uniting them at their upper ends, and leaving an interval _x y_, between
them, to place and work the movable frame B, vibrating round two fixed
points _a a_, placed laterally opposite each other, in the middle of the
space _x y_, _fig._ 566.
C, is a piece of iron with a peculiar curvature, seen in front, _fig._
566., and in profile, _figs._ 567. and 568. It is fixed on one side upon
the upper cross-bar of the frame B, and on the other, to the
intermediate cross-bar _b_ of the same frame, where it shows an inclined
curvilinear space _c_, terminated below by a semi-circle.
[Illustration: 569 570]
D, is a square wooden axis, movable upon itself round two iron pivots,
fixed into its two ends; which axis occupies the bottom of the movable
frame B. The four faces of this square axis are pierced with three
round, equal, truly-bored holes, arranged in a quincunx. The teeth _a_,
_fig._ 570., are stuck into each face, and correspond to holes _a_,
_fig._ 573., made in the cards which constitute the endless chain for
the healds; so that in the successive application of the cards to each
face of the square axis, the holes pierced in one card may always fall
opposite to those pierced in the other. The right-hand end of the
square axis, of which a section is shown in double size, _fig._ 569.,
carries two square plates of sheet iron _d_, kept parallel to each other
and a little apart, by four spindles _e_, passed opposite to the
corners. This is a kind of lantern, in whose spindles, the hooks of the
levers _f f´_, turning round fixed points _g g´_ beyond the right hand
upright A, catch hold, either above or below at the pleasure of the
weaver, according as he merely pulls or lets go the cord _z_, during the
vibratory movement of the frame B.
E is a piece of wood shaped like a T, the stem of which prolonged
upwards, passes freely through the cross-bar _b_, and through the upper
cross-bar of the frame B, which serve as guides to it. The head of the T
piece being applied successively against the two spindles _e_, placed
above in a horizontal position, first by its weight, and then by the
spiral spring _h_, acting from above downwards, keeps the square axis in
its position, while it permits it to turn upon itself in the two
directions. The name _press_ is given to the assemblage of all the
pieces which compose the movable frame B B.
F is a cross-bar made to move in a vertical direction by means of the
lever G, in the notches or grooves _i_, formed within the fixed uprights
A.
H, is a piece of bent iron, fixed by one of its ends with a nut and
screw, upon the cross-bar F, out of the vertical plane of the piece C.
Its other end carries a friction roller J, which working in the
curvilinear space _c_ of the piece C, forces this, and consequently the
frame B to recede from the perpendicular, or to return to it, according
as the cross-bar F is in the top or bottom of its course, as shown in
_figs._ 567. and 568.
I, cheeks of sheet iron attached on either side to the cross-bar F,
which serve as a safe to a kind of claw K, composed here of eight small
metallic bars, seen in section _fig._ 567. and 568., and on a greater
scale in _fig._ 570.
J, upright skewers of iron wire, whose tops bent down hook-wise,
naturally place themselves over the little bars K. The bottom of these
spindles likewise hooked in the same direction as the upper ones,
embraces small wooden bars _l_, whose office is to keep them in their
respective places, and to prevent them from twirling round, so that the
uppermost hooks may be always directed towards the small metallic bars
upon which they impend. To these hooks from below are attached strings,
which after having crossed a fixed board _m n_, pierced with
corresponding holes for this purpose, proceed next to be attached to the
threads of the loops destined to lift the warp threads. K K, horizontal
spindles or needles, arranged here in eight several rows, so that each
spindle corresponds both horizontally and vertically to each of the
holes pierced in the four faces of the square axis D. There are
therefore as many of these spindles as there are holes in one of the
faces of the square.
[Illustration: 571]
_Fig._ 571. represents one of these horizontal spindles. _n_ is an
eyelet through which the corresponding vertical skewer passes. _o_
another elongated eyelet, through which a small fixed spindle passes to
serve as a guide, but which does not hinder it from moving length-wise,
within the limits of the length of the eyelet. P, small spiral springs
placed in each hole of the case _q q_, _fig._ 570. They serve the
purpose of bringing back to its primitive position, every corresponding
needle, as soon as it ceases to press upon it.
[Illustration: 572 573]
_Fig._ 572. represents the plan of the upper row of horizontal needles.
_Fig._ 573. is a fragment of the endless chain, formed with perforated
cards, which are made to circulate or travel by the rotation of the
shaft D. In this movement, each of the perforated cards, whose position,
form, and number, are determined by the operation of tying-up of the
warp, comes to be applied in succession against the four faces of the
square axis or drum, leaving open the corresponding holes, and covering
those upon the face of the axis, which have no corresponding holes upon
the card.
Now let us suppose that the _press_ B is let down into the vertical
position shown in _fig._ 568.; then the card applied against the left
face of the axis, leaves at rest or untouched the whole of the
horizontal spindles (skewers), whose ends correspond to these holes, but
pushes back those which are opposite to the unpierced part of the card;
thereby the corresponding upright skewers, 3. 5. 6. and 8. for example,
pushed out of the perpendicular, unhook themselves from above the bars
of the claw, and remain in their place, when this claw comes to be
raised by means of the lever G; and the skewers 1. 2. 4. and 7., which
have remained hooked on, are raised along with the warp threads attached
to them. Then by the passage across of a shot of the colour, as well as
a shot of the common weft, and a stroke of the lay after shedding the
warp and lowering the press B, an element or point in the pattern is
completed.
The following card, brought round by a quarter revolution of the axis,
finds all the needles in their first position, and as it is necessarily
perforated differently from the preceding card, it will lift another
series of warp threads; and thus in succession for all the other cards,
which compose a complete system of a figured pattern.
This machine, complicated in appearance, and which requires some pains
to be understood, acts however in a very simple manner. Its whole play
is dependent upon the movement of the lever G, which the weaver himself
causes to rise and fall, by means of a peculiar pedal; so that without
the aid of any person, after the piece is properly read in and mounted,
he can execute the most complex patterns, as easily as he could weave
plain goods; only attending to the order of his weft yarns, when these
happen to be of different colours.
If some warp yarns should happen to break without the weaver observing
them, or should he mistake his coloured shuttle yarns, which would so
far disfigure the pattern, he must undo his work. For this purpose, he
makes use of the lower hooked lever _f´_, whose purpose is to make the
chain of the card go backwards, while working the loom as usual,
withdrawing at each stroke the shot both of the ground and of the
figure. The weaver is the more subject to make mistakes, as the figured
side of the web is downwards, and it is only with the aid of a bit of
looking-glass that he takes a peep of his work from time to time. The
upper surface exhibits merely loose threads in different points,
according as the pattern requires them to lie upon the one side or the
other.
Thus it must be evident, that such a number of paste-boards are to be
provided and mounted as equal the number of throws of the shuttle
between the beginning and end of any figure or design which is to be
woven; the piercing of each paste-board individually, will depend upon
the arrangement of the lifting rods, and their connection with the warp,
which is according to the design and option of the workman; great care
must be taken that the holes come exactly opposite to the ends of the
needles; for this purpose two large holes are made at the ends of the
paste-boards, which fall upon conical points, by which means they are
made to register correctly.
It will be hence seen, that, according to the length of the figure, so
must be the number of paste-boards, which may be readily displaced so as
to remount and produce the figure in a few minutes, or remove it, or
replace it, or preserve the figure for future use. The machine, of
course, will be understood to consist of many sets of the lifting rods
and needles, shown in the diagram, as will be perceived by observing the
disposition of the holes in the paste-board; those holes, in order that
they may be accurately distributed, are to be pierced from a gauge, so
that not the slightest variation shall take place.
To form these card-slips, an ingenious apparatus is employed, by which
the proper steel punches required for the piercing of each distinct
card, are placed in their relative situations preparatory to the
operation of piercing, and also by its means a card may be punched with
any number of holes at one operation. This disposition of the punches is
effected by means of rods connected to cords disposed in a frame, in the
nature of a false simple, on which the pattern of the work to be
performed is first read in.
These improved pierced cards, slips, or paste-boards, apply to a weaving
apparatus, which is so arranged that a figure to be wrought can be
extended to any distance along the loom, and by that means the loom is
rendered capable of producing broad figured works; having the long lever
G placed in such a situation that it affords power to the foot of the
weaver, and by this means enables him to draw the heaviest morintures
and figured works, without the assistance of a draw-boy.
The machinery for arranging the punches, consists of a frame with four
upright standards and cross-pieces, which contains a series of endless
cords passing under a wooden roller at bottom, and over pulleys at the
top. These pulleys are mounted on axles in two frames, placed obliquely
over the top of the standard frame, which pulley-frames constitute the
table commonly used by weavers.
[Illustration: 574]
In order better to explain these endless cords, _fig._ 574. represents a
single endless cord 1, 1, which is here shown in operation, and part of
another endless cord 2, 2, shown stationary. There must be as many
endless cords in this frame as needles in the weaving-loom. _a_ is the
wooden cylinder, revolving upon its axis at the lower part of the
standards; _b b_, the two pulleys of the pulley-frames above, over which
the individual endless cord passes; _c_ is a small traverse ring. To
each of these rings a weight is suspended by a single thread, for the
purpose of giving tension to the endless cord. _d_ is a board resembling
a common comber-bar, which is supported by the cross-bars of the
standard frame, and is pierced with holes, in situation and number,
corresponding with the perpendicular threads that pass through them;
which board keeps the threads distinct from each other.
At _e_, the endless cord passes through the eyes of wires resembling
needles, which are contained in a wooden box placed in front of the
machine, and shown in this figure in section only. These wires are
called the _punch-projectors_; they are guided and supported by
horizontal rods and vertical pins, the latter of which pass through
loops formed at the hinder part of the respective wires. At _f_ are two
horizontal rods extending the whole width of the machine, for the
purpose of producing the cross in the cords; _g_ is a thick brass plate,
extending along in front of the machine, and lying close to the box
which holds the _punch-projectors_; this plate _g_, shown also in
section, is called the _punch-holder_; it contains the same number of
apertures as there are punch-projectors, and disposed so as to
correspond with each other. In each of these apertures, there is a punch
for the purpose of piercing the cards, slips, or pasteboards with holes;
_h_ is a thick steel plate of the same size as _g_, and shown likewise
in section, corresponding also in its number of apertures, and their
disposition, with the punch-projectors and the punch-holder. This plate
_h_, is called the _punch-receiver_.
The object of this machine is to transfer such of the punches as may be
required for piercing any individual card from the punch-holder _g_,
into the punch-receiver _h_; when they will be properly situated, and
ready for piercing the individual card or slip, with such holes as have
been read in upon the machine, and are required for permitting the warp
threads to be withdrawn in the loom, when this card is brought against
the ends of the needles. The process of transferring the patterns to the
punches will be effected in the following manner.
The pattern is to be read in, according to the ordinary mode, as in a
false simple, upon the endless cords below the rods _f_, and passed
under the revolving wooden cylinder _a_, to a sufficient height for a
person in front of the machine to reach conveniently. He there takes the
upper threads of the pattern, called the _beard_, and draws them forward
so as to introduce a stick behind the cords thus advanced, as shown by
dots, for the purpose of keeping them separate from the cords which are
not intended to be operated upon. All the punch-projectors which are
connected with the cords brought forward, will be thus made to pass
through the corresponding apertures of the punch-holder _g_, and by this
means will project the punches out of these apertures, into
corresponding apertures of the punch-receiver _h_. The punches will now
be properly arranged for piercing the required holes on a card or slip,
which is to be effected in the following manner.
Remove the punch-receivers from the front of the machine; and having
placed one of the slips of card or pasteboard between the two folding
plates of metal, completely pierced with holes corresponding to the
needles of the loom, lay the punch-receiver upon those perforated
plates; to which it must be made to fit by mortises and blocks, the
cutting parts of the punches being downwards. Upon the back of the
punch-receiver is then to be placed a plate or block, studded with
perpendicular pins corresponding to the above described holes, into
which the pins will fall. The plates and the blocks thus laid together,
are to be placed under a press, by which means the pins of the block
will be made to pass through the apertures of the punch-receiver; and
wherever the punch has been deposited in the receiver by the above
process, the said punches will be forced through the slip of pasteboard,
and pierced with such holes as are required for producing the figured
design in the loom.
Each card being thus pierced, the punch-receiver is returned to its
place in front of the machine, and all the punches forced back again
into the apertures of the punch-holder as at first. The next set of
cords is now drawn forward by the next _beard_, as above described,
which sends out the _punch-projectors_ as before, and disposes the
punches in the punch-receiver, ready for the operation of piercing the
next card. The process being thus repeated, the whole pattern is, by a
number of operations, transferred to the punches, and afterwards to the
cards or slips, as above described.
JADE; axe-stone; (_Nephrite_, _Ceraunite_, Fr.) is a mineral commonly of
a greenish colour, compact, and of a fatty lustre. Spec. grav. 2·95;
scratches glass, is very tough; fuses into a white enamel. Its
constituents are, silica 50·5; alumina 10; magnesia 31; oxide of iron
5·50; oxide of chrome 0·05; water 2·75. It comes from China, is used
among rude nations for making hatchets; and is susceptible of being cut
into any form.
JAPANNING, is a kind of varnishing or lacquering, practised with
excellence by the Japanese, whence the name. See VARNISH.
JASPER; (_Jaspe calcedoine_, Fr.; _Jaspis_, Germ.) is a sub species of
calcedony quartz, of which there are five varieties. 1. The Egyptian red
and brown, with ring or tendril-shaped delineations. 2. Striped jasper.
3. Porcelain jasper. 4. Common jasper. 5. Agate jasper. The prettiest
specimens are cut for seals, and for the inferior kinds of jewellery
ornaments. See LAPIDARY.
ICEHOUSE; (_Glacière_, Fr.; _Eishaus_, Germ.) Under the article
FREEZING, I have enumerated the different artificial methods of
producing cold. But for the uses of common life, in these climates, the
most economical and convenient means of refrigeration in hot weather may
be procured by laying up a store of ice in winter, in such circumstances
as will preserve it solid during summer.
An icehouse should not be regarded as an object of mere luxury, for
pleasing the palates of gourmands with iced creams and orgeats. In the
southern countries of Europe it is considered among people in easy
circumstances as an indispensable appendage to a country mansion. During
the Dog-days, especially at those periods, and in those districts where
the _sirocco_ blows, a lassitude and torpor of mind and body supervene,
with indigestion or total loss of appetite, and sometimes dysenteries,
which are obviously occasioned by the excessive heat, and are to be
prevented or counteracted chiefly by the use of cold beverages. By
giving tone to the stomach, iced drinks immediately restore the
functions of the nervous and muscular systems when they are languid;
while they enable persons in health to endure without much inconvenience
an atmosphere so close and sultry as would be intolerable without this
remedy. Icehouses, moreover, afford to country gentlemen, a great
advantage in enabling them to preserve their fish, butcher meat, dead
poultry, and game, which would otherwise, in particular states of the
weather, immediately spoil. Considering at how little expense and
trouble an icehouse can be constructed, it is surprising that any
respectable habitation in the country should not have one attached to
it. The simplest and most scientific form is a double cone, that is, two
cones joined base to base; the one being of stones or brickwork, sunk
under ground with its apex at the bottom, into which the ice is rammed;
the other being a conical roof of carpentry covered with thatch, and
pointed at top. The entrance should be placed always on the north side;
it should consist of a corridor or porch with double doors, and be
screened from the sunbeams by a small shrubbery. Such are, in general,
the principles upon which an icehouse should be formed; but they will be
better understood by the following explanation and figure.
A dry sandy soil should be selected, and, if possible, a spot sheltered
by a cliff or other natural barrier from the direct rays of the sun.
Here a cavity is to be dug about 16 feet in diameter, terminating below
like the point of a sugar loaf. Its ordinary depth, for a moderate
family, may be about 24 feet; but the larger its dimensions are, the
longer will it preserve the ice, provided it be filled. In digging, the
workman should slope the ground progressively towards the axis of the
cone, to prevent the earth falling in. This conical slope should be
faced with brick or stone work about one foot thick, and jointed with
Roman cement so as to be air and water tight. A well is to be excavated
at the bottom two feet wide and four deep, covered at top with an iron
grating for supporting the ice, and letting the water drain away.
The upper cone may likewise be built of brickwork, and covered with
thatch; such a roof would prove the most durable. This is the
construction shown in _fig._ 575. Whatever kind of roof be preferred,
there must be left in it an oblong passage into the interior. This porch
should face the north, and be at least 8 feet long by 2-1/2 feet wide;
and perfectly closed by a well-fitted door at each end. All round the
bottom of this conical cover, a gutter should be placed to carry off the
rain to a distance from the icehouse, and prevent the circumjacent
ground from getting soaked with moisture.
[Illustration: 575]
_Fig._ 575. shows the section of a well-constructed icehouse. Under the
ice-chamber A the ice is rammed into the space B. C is the grate of the
drain-sink D. The portion E E is built in brick or stone; the base L of
the ice-chamber slopes inwards towards the centre at C. The upper part
of the brickwork E E is a little way below the level of the ground. The
wooden frame work F F F F forms the roof, and is covered with thick
thatch. G H is the wooden work of the door I. At K the bucket is seen
for lifting up a charge of ice, by means of the cord J passing over the
pulley M, which enables the servant to raise it easily.
The icehouse should have no window to admit light; but be, so to speak,
hermetically sealed in every point, except at its cess-pool, which may
terminate in a water trap to prevent circulation of air.
A clear day should be selected for charging the icehouse; but before
beginning to fill, a quantity of long dry straw should be laid on the
bottom crosswise; and as the ice is progressively introduced, straw is
to be spread against the conical sides, to prevent the ice from coming
into contact with the brick or stone work. The more firmly compacted the
ice is, the better does it keep; with which view it should be broken
into pieces with mallets before being thrown in. No layers of straw
should be stratified among the ice, for they would make its body porous.
Some persons recommend to pour in a little water with the successive
layers of ice, in order to fill up its small crevices, and convert the
whole into one mass.
Over the top layer a thick bed of straw should be spread, which is to be
covered with boards surmounted with heavy stones, to close up the
interstices in the straw. The inner and outer doors should never be
opened at once; but the one should always be shut before the other is
opened.
Dry snow well rammed keeps equally well with hard ice, if care be taken
to leave no cavities in the mass, and to secure its compactness by
sprinkling a little water upon the successive charges.
To facilitate the extraction of the ice, a ladder is set up against its
sloping wall at one side of the door, and left there during the season.
JELLY, VEGETABLE, of ripe currants and other berries, is a compound of
mucilage and acid, which loses its power of gelatinizing by prolonged
ebullition.
JELLY, ANIMAL; see GELATINE, GLUE, and ISINGLASS.
JET; (_Jaiet_ or _jais_, Fr.) a species of pitch-coal or glance-coal,
which, being found abundantly in a beautiful compact form, in the valley
of Hers, arrondissement of Pamiers, department of the Arriège, has been
worked up extensively there from time immemorial, into a multitude of
ornamental articles. With this black lignite, buttons, crosses,
rosaries, necklaces, ear-drops, bracelets, waist-buckles, &c. are made,
which were at one time much worn by ladies for mourning dresses. The
greater number of these ornaments are fashioned upon grindstones which
turn in a horizontal direction, and are kept continually wet; others are
turned at the lathe, or shaped by files.
About 40 years ago this manufacture employed from 1000 to 1200
operatives; at present it gives bread to only 60. This falling off may
be ascribed to the successful imitation of the jet articles by those of
black glass, which are equally beautiful, and not nearly so apt to lose
their polish by use.
IMPERMEABLE, is the epithet given to any kind of textile fabric,
rendered water-proof by one or other of the following substances:--
1. Linseed oil to which a drying quality has been communicated by
boiling with litharge or sugar of lead, &c.