3. the prevention of any of the damages to which hats are liable in the
dyeing;
4. the accomplishment of the dyeing process in a much shorter time than
by the usual methods, and consequently lessening the injurious effects
of the dye-bath upon the texture of the hat.
[Illustration: 544]
_Fig._ 544. shows one method of constructing the apparatus. _a a_ is a
semi-cylindrical shaped copper vessel, with flat ends, in which the
dyeing process is carried on. _b b b_ is a wheel with several circular
rims mounted upon arms, which revolve upon an axle _c_. In the face of
these rims a number of pegs or blocks are set at nearly equal distances
apart, upon each of which pegs or blocks it is intended to place a hat,
and as the wheel revolves, to pass it into and out of the dyeing liquor
in the vat or copper. This wheel may be kept revolving with a very slow
motion, either by geer connecting its axle, _c_, with any moving power,
or it may be turned round by hand, at intervals of ten minutes; whereby
the hats hung upon the pegs, will be alternately immersed for the space
of ten minutes in the dyeing liquor, and then for the same space exposed
to the atmospheric air. In this way, the process of dyeing, it is
supposed, may be greatly facilitated, and improved, as the occasional
transition from the dye vat into the air, and from the air again into
the bath, will enable the oxygen of the atmosphere to strike the dye
more perfectly and expeditiously into the materials of which the hat is
composed, than by a continued immersion in the bath for a much longer
time.
[Illustration: 545]
A variation in the mode of performing this process is suggested, and the
apparatus _fig._ 545. is proposed to be employed, _a a_ is a square vat
or vessel containing the dyeing liquor; _b b_ is a frame or rack having
a number of pegs placed in it for hanging the hats upon, which are about
to be dyed, in a manner similar to the wheel above described. This frame
or rack is suspended by cords from a crane, and may in that way be
lowered down with the hats into the vat, or drawn up and exposed in the
air; changes which may be made every 10 or 20 minutes.
I have seen apparatus of this kind doing good work in the hat-dyeing
manufactories of London, that being a department of the business with
which the Union has not thought it worth their while to interfere.
[Illustration: 546]
Mr. William Hodge’s patent improvements in hat dyeing, partly founded
upon an invention of Mr. Bowler, consist, first in causing every
alternate frame to which the suspenders or blocks are to be attached, to
slide in and out of grooves, for the purpose of more easily removing the
said suspenders when required. _Fig._ 546. represents the improved
dyeing frame, consisting of two circular rims, _a a_, which are
connected together at top and bottom, by three fixed perpendicular bars
or the frame-work _b b b_. Two other perpendicular frames _c c_, similar
to the former, slide in grooves, _d d d d_, fixed to the upper and lower
rims. These grooves have anti-friction rollers in them, for the purpose
of making the frames _c c_, to slide in and out more freely. The
suspenders or substitutes for blocks, by these means, may be more easily
got at by drawing out the frames _c c_, about half way, when the
suspenders, which are attached to the frames with the hats upon them,
may be easily reached, and either removed or altered in position; and
when it is done on one side, the sliding frame may be brought out on the
other, and the remaining quantity of “suspenders” undergo the same
operation.
The patentee remarks, that it is well known to all hat dyers, that after
the hats have been in the dyeing liquor some time, they ought to be
taken out and exposed to the action of the atmospheric air, when they
are again immersed in the copper, that part of the hat which was
uppermost in the first immersion, being placed downwards in the second.
This is done for the purpose of obtaining an uniform and regular dye.
The patentee’s mode of carrying this operation into effect, is shown in
the figure: _e e_ are pivots for the dyeing-frame to turn upon, which is
supported by the arms _f_, from a crane above. The whole apparatus may
be raised up or lowered into the copper by means of the crane or other
mechanism. When the dyeing-frame is raised out of the copper, the whole
of the suspenders or blocks are reversed, by turning the apparatus over
upon the pivots _e e_, and thus the whole surfaces of the hats are
equally acted upon by the dyeing material.
It should be observed, that when the dyeing-frame is raised up out of
the copper, it should be tilted on one side, so as to make all the
liquor run out of the hats, as also to cause the rims of the hats to
hang down, and not stick to the body of the hat, or leave a bad place or
uneven dye upon it. The second improvement described by the patentee, is
the construction of “suspenders,” to be substituted instead of the
ordinary blocks.
[Illustration: 547 548]
These “suspenders” are composed of thin plates of copper, bent into the
required form, that is, nearly resembling that of a hat block, and made
in such a manner as to be capable of contraction and expansion to suit
different sized hats, and keep them distended, which may be altered by
the workman at pleasure, when it is required to place the hats upon
them, or remove them therefrom. The dyeing-frame at _fig._ 546. is shown
with only two of these “suspenders,” in order to prevent confusion. One
of these suspenders is represented detached at _fig._ 547., which
exhibits a side view; and _fig._ 548. a front view of the same. It will
be seen by reference to the figure, that the suspenders consist of two
distinct parts, which may be enlarged or collapsed by a variety of
means, and which means may be suggested by any competent mechanic. The
two parts of the suspenders are proposed to be connected together by
arms _g g_, and at the junction of these arms a key is connected for
turning them round when required. It will be seen on reference to the
front view, _fig._ 548., that the “suspenders” or substitutes for
blocks, are open at the top or crown part of the hat; this is for the
purpose of allowing the dyeing liquor to penetrate.
From the mixture of copperas and verdigris employed in the hat-dye, a
vast quantity of an ochreous muddy precipitate results, amounting to no
less than 25 per cent. of the weight of the copperas. This iron mud
forms a deposit upon the hats, which not only corrodes the fine
filaments of the beaver, but causes both them and the felt stuff to turn
speedily of a rusty brown. There is no process in the whole circle of
our manufactures, so barbarous as that of dyeing stuff hats. No ray of
chemical science seems hitherto to have penetrated the dark recesses of
their dye shops. Some hatters have tried to remove this corrosive brown
ochre by a bath of dilute sulphuric acid, and then counteract the evil
effect of the acid upon the black dye by an alkaline bath; but with a
most unhappy effect. Hats so treated are most deceptious and
unprofitable; as they turn of a dirty brown hue, when exposed for a few
weeks to sunshine and air.
HEALDS, is the harness for guiding the warp threads in a loom; that is,
for lifting a certain number of them alternately to open the shed, and
afford passage to the decussating weft threads of the shuttle. See
WEAVING.
HEARTH; (_Foyer_, Fr.; _Heerde_, Germ.) is the flat or hollow space in a
smelting furnace upon which the ore and fluxes are subjected to the
influence of flame. See COPPER, IRON, METALLURGY, &c.
HEAT, is that power or essence called caloric, the discussion of whose
habitudes with the different kinds of matter belongs to the science of
chemistry.
HEAT-REGULATOR. The name given by M. Bonnemain to an ingenious apparatus
for regulating the temperature of his incubating stove rooms. See
INCUBATION, ARTIFICIAL, for the manner of applying the Heat-Regulator.
[Illustration: 549 549*]
The construction of the regulator is founded upon the unequal dilatation
of different metals by the same degree of heat. A rod of iron _x_,
_fig._ 549., is tapped at its lower end into a brass nut _y_, enclosed
in a leaden box or tube, terminated above by a brass collet _z_. This
tube is plunged into the water of the boiler, alongside of the
smoke-pipe. (_Fig._ 549*. is a bird’s-eye view of the dial, &c.) The
expansion of the lead being more than the iron for a like degree of
temperature, and the rod enclosed within the tube being less easily
warmed, whenever the heat rises to the desired pitch, the elongation of
the tube puts the collet _z_ in contact with the heel _a_, of the bent
lever _a_, _b_, _d_; thence the slightest increase of heat lengthens the
tube anew, and the collet lifting the heel of the lever, depresses its
other end _d_ through a much greater space, on account of the relative
lengths of its legs. This movement operates near the axis of a
balance-bar _e_, sinks one end of this, and thereby increases the extent
of the movement which is transmitted directly to the iron skewer _v_.
This pushing down a swing register diminishes or cuts off the access of
air to the fire-place. The combustion is thereby obstructed, and the
temperature falling by degrees, the tube shrinks and disengages the heel
of the lever. The counterpoise _g_, fixed to the balance-beam _e_,
raises the other extremity of this beam, by raising the end _d_ of the
lever as much as is necessary to make the heel bear upon the collet of
the tube. The swing register acted upon by this means, presents a
greater section to the passage of the air; whence the combustion is
increased. To counterbalance the effect of atmospheric changes, the
iron stem which supports the regulator is terminated by a dial disc,
round the shaft of the needle above _h_, _fig._ 549*.; on turning this
needle, the stem below it turns, as well as a screw at its under end,
which raises or lowers the leaden tube. In the first case, the heel
falls, and opens the swing register, whence a higher temperature is
required to shut it, by the expansion of the tube. We may thus obtain a
regularly higher temperature. If, on the contrary, we raise the tube by
turning the needle in the other direction, the register presents a
smaller opening, and shuts at a lower temperature; in this case, we
obtain a regularly lower temperature. It is therefore easy, says M.
Bonnemain, to determine _à priori_ the degree of temperature to be given
to the water circulating in the stove pipes. In order to facilitate the
regulation of the apparatus, he graduated the disc dial, and inscribed
upon its top and bottom, the words, Strong and Weak heat. See
THERMOSTAT, for another HEAT-REGULATOR.
HEAVY SPAR, _sulphate of Baryta, or Cawk_; (_Spath pesant_, Fr.;
_Schwerspath_, Germ.) is an abundant mineral, which accompanies veins of
lead, silver, mercury, &c. but is often found, also, in large masses.
Its colour is usually white, or flesh-coloured. It occurs in many
crystalline forms, of which the cleavage is a right rhomboidal prism. It
is met with also of a fibrous, radiated, and granular structure. Its
spec. grav. varies from 4·1 to 4·6. It has a strong lustre, between the
fatty and the vitreous. It melts at 35° Wedgew. into a white opaque
enamel. Its constituents are 65·63 baryta, and 34·37 sulphuric acid. It
is decomposed by calcination in contact with charcoal at a white heat,
into sulphuret of baryta; from which all the baryta salts may be readily
formed. Its chief employment in commerce is for adulterating white lead;
a purpose which it readily serves on account of its density. Its
presence here is easily detected by dilute nitric acid, which dissolves
the carbonate of lead, and leaves the heavy spar. It is also a useful
ingredient in some kinds of pottery, and glass.
HECKLE; (_Seran_, Fr.; _Hechel_, Germ.) is an implement for dissevering
the filaments of flax, and laying them in parallel stricks or tresses.
See FLAX.
HELIOTROPE; is a variety of jasper, mixed with chlorite, green earth,
and diallage; occasionally marked with blood-red points; whence its
vulgar name of _bloodstone_.
HEMATINE; is the name given by its discoverer Chevreul to a crystalline
substance, of a pale pink colour, and brilliant lustre when viewed in a
lens, which he extracted from logwood, the _hæmatoxylon Campechianum_ of
botanists. It is, in fact, the characteristic principle of this
dye-wood. To procure hematine, digest during a few hours ground logwood
in water heated to a temperature of about 130° F.; filter the liquor,
evaporate it to dryness by a steam bath, and put the extract in alcohol
of 0·835 for a day. Then filter anew, and after having inspissated the
alcoholic solution by evaporation, pour into it a little water,
evaporate gently again, and then leave it to itself in a cool place. In
this way a considerable quantity of crystals of hematine will be
obtained, which may be readily purified by washing with alcohol and
drying.
When subjected to dry distillation in a retort, hematine affords all the
usual products of vegetable bodies, along with a little ammonia; which
proves the presence of azote. Boiling water dissolves it abundantly, and
assumes an orange-red colour, which passes into yellow by cooling, but
becomes red again with heat. Sulphurous acid destroys the colour of
solution of hematine. Potash and ammonia convert into a dark purple-red
tint, the pale solution of hematine; when these alkalis are added in
large quantity, they make the colour, violet blue, then brown-red, and
lastly brown-yellow. By this time, the hematine has become decomposed,
and cannot be restored to its pristine state by neutralizing the alkalis
with acids.
The waters of baryta, strontia, and lime exercise an analogous power of
decomposition; but they eventually precipitate the changed colouring
matter.
A red solution of hematine subjected to a current of sulphuretted
hydrogen becomes yellow; but it resumes its original hue when the
sulphuretted hydrogen is removed by a little potash.
The protoxide of lead, the protoxide of tin, the hydrate of peroxide of
iron, the hydrate of oxides of copper and nickel, oxide of bismuth,
combine with hematine, and colour it blue with more or less of a violet
cast.
Hematine precipitates glue from its solution in reddish flocks. This
substance has not hitherto been employed in its pure state; but as it
constitutes the active principle of logwood, it enters as an ingredient
into all the colours made with that dye stuff.
These colours are principally violet and black. Chevreul has proposed
hematine as an excellent test of acidity.
HEMATITE; (_Fer Oligiste_, Fr.; _Rotheisenstein_, Germ.) is a native
reddish-brown peroxide of iron, consisting of oxygen 30·66; iron 60·34.
It is the kidney ore of Cumberland, which is smelted at Ulverstone with
charcoal, into excellent steel iron.
HEMP; (_Chanvre_, Fr.; _Hanf_, Germ.) is the fibrous rind of the bark of
the _cannabis sativa_, which is spun into strands or yarn for making
ropes, sail-cloth, &c. It is prepared for spinning in the same way as
flax, which see. _Hemp-seed_ contains an oil which is employed for
making soft soap, for painting, and for burning in lamps. See OILS.
Importation of undressed hemp for home consumption; and amount of duty,
in
1837. 1838. | 1837. 1838.
Cwts. 596,994·3 | 667,017 | _£_2487 | _£_2780
HEPAR; which signifies liver in Latin, was a name given by the older
chemists to some of those compounds of sulphur with the metals which had
a liver-brown colour. Thus the sulphuret of potassium was called liver
of sulphur.
HEPATIC AIR; sulphuretted hydrogen gas.
HERMETICAL SEAL, is an expression derived from Hermes, the fabulous
parent of Egyptian chemistry, to designate the perfect stoppage of a
hollow vessel, by the cementing or melting of the lips of its orifice;
as in the case of a glass thermometer, or matrass.
HIDE; (_Peau_, Fr.; _Haut_, Germ.) the strong skin of an ox, horse, or
other large animal. See LEATHER.
Importation of untanned hides for home consumption; and amount of duty,
in
1837. 1838. | 1837. 1838.
332,877 | 301,890 | _£_46,190 | _£_36,647
HIRCINE; from _hircus_, a ram; is the name given by Chevreul to a liquid
fatty substance, which is mixed with the oleine of mutton suet, and
gives it its peculiar rank smell. Hircine is much more soluble in
alcohol than oleine. It produces _hircic_ acid by saponification.
HOG’s LARD; see FATS.
HONEY; (_Mel_, Fr.; _Honig_, Germ.) is a sweet viscid liquor, elaborated
by bees from the sweet juices of the nectaries of flowers, and deposited
by them in the waxen cells of their combs. Virgin honey is that which
spontaneously flows with a very gentle heat from the comb, and common
honey is that which is procured by the joint agency of pressure and
heat. The former is whitish or pale yellow, of a granular texture, a
fragrant smell, and a sweet slightly pungent taste; the latter is darker
coloured, thicker, and not so agreeable either in taste or smell. Honey
would seem to be merely collected by the bees, for it consists of merely
the vegetable products; such as the sugars of grape, gum, and manna;
along with mucilage, extractive matter, a little wax, and acid.
HONEY-STONE; (_Mellite_, Fr.; _Honigstein_, Germ.) is a mineral of a
yellowish or reddish colour, and a resinous aspect, crystallizing in
octahedrons with a square base; specific gravity 1·58. It is harder than
gypsum, but not so hard as calc-spar; it is deeply scratched by a steel
point; very brittle; affords water by calcination; blackens, then burns
at the flame of the blowpipe, and leaves a white residuum which becomes
blue, when it is calcined after having been moistened with a drop of
nitrate of cobalt. It is a mellate of alumina, and consists of:
Klaproth. Wöhler.
Mellitic acid 46 44·4
Alumina 16 14·5
Water 38 41·1
--- -----
100 100·0
The honey-stone, like amber, belongs to the geological formation of
lignites. It has been hitherto found clearly in only one locality, at
Artern in Thuringia.
HOP; (_Houblon_, Fr.; _Hopfen_, Germ.) is the name of a well-known plant
of the natural family of Urticeæ, and of the dioecia pentandria of
Linnæus. The female flowers, placed upon different plants from the male,
grow in ovoid cones formed of oval leafy scales, concave, imbricated,
containing each at the base an ovary furnished with two tubular open
styles, and sharp pointed stigmata. The fruit of the hop is a small
rounded seed, slightly compressed, brownish coloured, enveloped in a
scaly calyx, thin but solid, which contains, spread at its base, a
granular yellow substance, appearing to the eye like a fine dust, but in
the microscope seen to be round, yellow, transparent grains; deeper
coloured, the older the fruit. This secretion, which constitutes the
useful portion of the hop, has been examined in succession by Ives,
Planche, Payen, and Chevallier. I have given a pretty full account of
the results of their researches in treating of the hop, under the
article BEER.
HORDEINE, is the name given by Proust to the peculiar starchy matter of
barley. It seems to be a mixture of the starch, lignine, and husks,
which constitutes barley meal. See BEER.
HORN; (Eng. and Germ.; _Corne_, Fr.) particularly of oxen, cows, goats,
and sheep, is a substance soft, tough semi-transparent, and susceptible
of being cut and pressed into a variety of forms; it is this property
that distinguishes it from bone. Turtle or tortoise shell seems to be of
a nature similar to horn, but instead of being of a uniform colour, it
is variegated with spots.
These valuable properties render horn susceptible of being employed in a
variety of works fit for the turner, snuff-box, and comb maker. The
means of softening the horn need not be described, as it is well known
to be by heat; but those of cutting, polishing, and soldering it, so as
to make plates of large dimensions, suitable to form a variety of
articles, may be detailed. The kind of horn to be preferred is that of
goats and sheep, from its being whiter and more transparent than the
horn of any other animals. When horn is wanted in sheets or plates, it
must be steeped in water, in order to separate the pith from the kernel,
for about fifteen days in summer, and a month in winter; and after it is
soaked, it must be taken out by one end, well shaken and rubbed in order
to get off the pith; after which it must be put for half an hour into
boiling water, then taken out, and the surface sawed even lengthways; it
must again be put into the boiling water to soften it, so as to render
it capable of separating; then, with the help of a small iron chisel, it
can be divided into sheets or leaves. The thick pieces will form three
leaves, those which are thin will form only two, whilst young horn,
which is only one quarter of an inch thick, will form only one. These
plates or leaves must again be put into boiling water, and when they are
sufficiently soft, they must be scraped with a sharp cutting instrument,
to render those parts that are thick even and uniform; they must be put
once more into the boiling water, and finally carried to the press.
At the bottom of the press employed, there must be a strong block, in
which is formed a cavity, of nine inches square, and of a proportionate
depth; the sheets of horn are to be laid within this cavity, in the
following manner: at the bottom, first a sheet of hot iron, upon this a
sheet of horn, next again a sheet of hot iron, and so on, taking care to
place at the top a plate of iron even with the last. The press must then
be screwed down tight.
There is a more expeditious process, at least in part, for reducing the
horn into sheets, when it is wanted very even. After having sawed it
with a very fine and sharp saw, the pieces must be put into a copper
made on purpose, and there boiled, until sufficiently soft, so as to be
able to be split with pincers; the sheets of horn must then be put in
the press, where they are to be placed in a strong vice, the chaps of
which are of iron and larger than the sheets of horn, and the vice must
be screwed as quick and tight as possible; let them cool in the press or
vice, or it is as well to plunge the whole into cold water. The last
mode is preferable, because the horn does not shrink in cooling. Now
draw out the leaves of horn, and introduce other horn to undergo the
same process. The horn so enlarged in pressing, is to be submitted to
the action of the saw, which ought to be set in an iron frame, if the
horn is wanted to be cut with advantage, in sheets of any desired
thickness, which cannot be done without adopting this mode. The thin
sheets thus produced must be kept constantly very warm between plates of
hot iron to preserve their softness; every leaf being loaded with a
weight heavy enough to prevent its warping. To join the edges of these
pieces of horn together, it is necessary to provide strong iron moulds
suited to the shape of the article wanted, and to place the pieces in
contact with copper-plates or with polished metal surfaces against them;
when this is done, the whole is to be put into a vice and screwed up
tight, then plunged into boiling water, and after some time it is to be
removed from thence and immersed in cold water. The edges of the horn
will be thus made to cement together and become perfectly united.
To complete the polish of the horn, the surface must be rubbed with the
subnitrate of bismuth by the palm of the hand. The process is short, and
has this advantage, that it makes the horn dry promptly.
When it is wished to spot the horn in imitation of tortoise-shell,
metallic solutions must be employed as follows:--To spot it red, a
solution of gold in aqua regia must be employed; to spot it black, a
solution of silver in nitric acid must be used; and for brown, a hot
solution of mercury in nitric acid. The right side of the horn must be
impregnated with these solutions, and they will assume the colours
intended. The brown spots can be produced on the horn by means of a
paste made of red lead, with a solution of potash, which must be put in
patches on the horn, and subjected some time to the action of heat. The
deepness of the brown shades depends upon the quantity of potash used in
the paste, and the length of time the mixture lies on the horn. A
decoction of Brazil wood, or a solution of indigo, in sulphuric acid, or
a decoction of saffron, and Berbary wood may also be used. After having
employed these materials, the horn may be left for half a day in a
strong solution of vinegar and alum.
In France, Holland, and Austria, the comb-makers and horn-turners use
the clippings of horn, which are of a whitish yellow, and tortoise-shell
skins, out of which they make snuff-boxes, powder-horns, and many
curious and handsome things. They first soften the horn and shell in
boiling water, so as to be able to submit them to the press in iron
moulds, and by means of heat form them into one mass. The degree of heat
necessary to join the horn clippings must be stronger than that for
shell skins, and it can only be found out by experience. The heat must
not however be too great, for fear of scorching the horn or shell.
Considerable care is required in these operations, not to touch the horn
with the fingers, nor with any greasy body, because the grease will
prevent the perfect joining. Wooden instruments should be used to move
them, while they are at the fire, and for carrying them to the moulds.
In making a ring of horn for bell-pulls, &c., the required piece is to
be first cut out in the flat of its proper dimensions, and nearly in the
shape of a horse-shoe; it is then pressed in a pair of dies to give its
surface the desired pattern; but previous to the pressure, both the
piece of horn and the dies are to be heated; the piece of horn is to be
introduced between the dies, squeezed in a vice, and when cold, the
impression or pattern will be fixed upon the horn. One particular
condition, however, is to be observed in the construction of the dies,
for forming a ring. They are to be so made, that the open ends of the
horse-shoe piece of horn, after being pressed, shall have at one end a
nib, and at the other a recess of a dovetailed form, corresponding to
each other; and the second operation in forming this ring of horn is to
heat it, and place it in another pair of dies, which shall bring its
open ends together, and cause the dovetailed joints to be locked fast
into each other, which completes the ring, and leaves no appearance of
the junction.
In forming the handles of table knives and forks, or other things which
require to be made of two pieces, each of the two pieces or sides of the
handle is formed in a separate pair of dies; the one piece is made with
a counter-sunk groove along each side, and the other piece with
corresponding leaves or projecting edges. When these two pieces are
formed, by first being cut out of the flat horn, then pressed in the
dies in a heated state, for the purpose of giving the pattern, the two
pieces are again heated and put together, the leaves or edges of the one
piece dropping into the counter-sunk grooves of the other piece, and
being introduced between another pair of heated dies, the joints are
pressed together and the two pieces formed into one handle.
In making the knobs for drawers which have metal stems or pins to fasten
them into the furniture, the face of the knob is to be first made in a
die, as above described, and then the back part of the knob with a hole
in it; a metal disc of plate-iron is next provided, in which the metal
stem or screw pin is fixed, and the stem being passed through the
aperture in the back piece, and the two, that is, the back and front
pieces of horn put together, they are then heated and pressed in dies as
above described; the edge of the back piece falling into the
counter-sunk groove of the front piece, while by the heat they are
perfectly cemented together.
HORNSILVER; (_Argent Corné_, or _Kerargyre_, Fr; _Hornsilber_, Germ.) is
a white or brownish mineral, sectile like wax or horn; and crystallizing
in the cubic system. Its specific gravity varies from 4·75 to 5·55.
Insoluble in water; not volatile; fusible at the blowpipe, but difficult
of reduction by it. It deposits metallic silver when rubbed with water
upon a piece of clean copper or iron. It consists of 24·67 chlorine, and
75·32 silver.
Hornsilver is rare in the European mines, but it occurs in great
quantity in the districts of Zacatecas, Fresnillo, and Catarce, in
Mexico; and in Huantajaya, Yauricocha, &c., in Peru; where it is
abundantly mixed with the ores of hydrate of iron, called Pacos and
Colorados, interspersed with veins of metallic silver, which form
considerable deposits in the _penæan_ limestones. There it is profitably
mined as an ore of silver.
HORNSTONE; is a variety of rhomboidal quartz. Being both hard and tough,
it is well adapted to form the stones of pottery mills for grinding
flints; it is called chert in Derbyshire, where it abounds.
_Hornstone_ occurs under three modifications; splintery hornstone,
conchoidal hornstone, and woodstone. The colours of the first two are
gray, white, and red; they are all massive; dull, or of a glimmering
lustre. Translucent only on the thin edges. Difficult to break.
Hornstone is less brittle than flint; and by its infusibility before the
blowpipe it may be distinguished from petrosilex, which it resembles in
external appearance. The geological locality of hornstone is remarkable;
for it occurs in both ancient and recent formations. It is found
frequently in the veins that traverse primitive crystalline rocks,
filling up the interstices, and enveloping their metallic ores. In the
lead mine of Huelgoët in Brittany it is whitish; but its prevailing
colour is gray. It occurs likewise in the middle beds of the coarse
limestone (_calcaire grossier_) in the Paris basin, which is a
comparatively modern formation, as well as in the sand beds of the upper
parts of this district, near Saint Cloud, Neuilly, &c. The hornstone
which occurs in secondary limestone is called _chert_ by the English
miners. It is valuable for forming the grinding blocks of flint mills in
the pottery manufacture.
HORSE POWER, in steam engines, is estimated by Mr. Watt at 32,000 pounds
avoirdupois lifted one foot high per minute, for one horse. M.
D’Aubuisson, from an examination of the work done by horses in the
whims, or gigs (_machines à molettes_) for raising ore from the mines at
Freyberg, the horses being of average size and strength, has concluded
that the useful effect of a horse yoked during eight hours, by two
relays of four hours each, in a manege or mill course, may be estimated
at 40 kilogrammes raised 1 mètre per second; which is nearly 16,440
pounds raised one foot per minute; being very nearly one half of Mr.
Watt’s liberal estimate for the work of his steam engines.
HOSIERY; (_Bonnèterie_, Fr.; _Strumpfweberei_, Germ.) The _stocking
frame_, which is the great implement of this business, though it appears
at first sight to be a complicated machine, consists merely of a
repetition of parts easily understood, with a moderate degree of
attention, provided an accurate conception is first formed of the nature
of the hosiery fabric. This texture is totally different from the
rectangular decussation which constitutes cloth, as the slightest
inspection of a stocking will show; for this, instead of having two
distinct systems of thread, like the warp and the weft, which are woven
together, by crossing each other at right angles, the whole piece is
composed of a single thread united or looped together in a peculiar
manner, which is called stocking-stitch, and sometimes chain-work.
[Illustration: 550 551]
This is best explained by the view in _fig._ 550. A single thread is
formed into a number of loops or waves, by arranging it over a number of
parallel needles, as shewn at R: these are retained or kept in the form
of loops or waves, by being drawn or looped through similar loops or
waves formed by the thread of the preceding course of the work, S. The
fabric thus formed by the union of a number of loops is easily
unravelled, because the stability of the whole piece depends upon the
ultimate fastening of the first end of the thread; and if this is
undone, the loops formed by that end will open, and release the
subsequent loops one at a time, until the whole is unravelled, and drawn
out into the single thread from which it was made. In the same manner,
if a thread in a stocking piece fails, or breaks at any part, or drops a
stitch, as it is called, it immediately produces a hole, and the
extension of the rest can only be prevented by fastening the end. It
should be observed that there are many different fabrics of
stocking-stitch for various kinds of ornamental hosiery, and as each
requires a different kind of frame or machine to produce it, we should
greatly exceed our limits to enter into a detailed description of them
all. That species which we have represented in _fig._ 550. is the common
stocking-stitch used for plain hosiery, and is formed by the machine
called the common stocking-frame, which is the groundwork of all the
others. The operation, as we see, consists in drawing the loop of a
thread successively through a series of other loops, so long as the work
is continued, as is very plainly shown for one stitch in _fig._ 551.
There is a great variety of different frames in use for producing
various ornamental kinds of hosiery. The first, which forms the
foundation of the whole, is that for knitting plain hosiery, or the
common stocking-frame.
[Illustration: 552]
Of this valuable machine, the invention of Mr. Lee of Cambridge, a side
elevation is given in _fig._ 552., with the essential parts. The framing
is supported by four upright posts, generally of oak, ash, or other hard
wood. Two of these posts appear at A A, and the connecting cross rails
are at C C. At B is a small additional piece of framing, which supports
the hosier’s seat. The iron-work of the machine is bolted or screwed to
the upper rails of the frame-work, and consists of two parts. The first
rests upon a sole of polished iron, which appears at D, and to which a
great part of the machinery is attached. The other part, which is
generally called the carriage, runs upon the iron sole at D, and is
supported by four small wheels, or trucks, as they are called by the
workmen. At the upper part of the back standard of iron are joints, one
of which appears at Q; and to these is fitted a frame, one side of which
is seen extending to H. By means of these joints, the end at H may be
depressed by the hosier’s hand, and it returns, when relieved, by the
operation of a strong spring of tempered steel, acting between a cross
bar in the frame, and another below. The action of this spring is very
apparent in _fig._ 553. In the front of the frame, immediately opposite
to where the hosier sits, are placed the needles which form the loops.
These needles, or rather hooks, are more or less numerous, according to
the coarseness or fineness of the stocking; and this, although
unavoidable, proves a very considerable abatement of the value of a
stocking-frame. In almost every other machine (for example those
employed in spinning or weaving), it is easy to adapt any one either to
work coarser or finer work, as it may be wanted. But in the manufacture
of hosiery, a frame once finished, is limited for ever in its operation
to the same quality of work, with this exception, that by changing the
stuff, the work may be made a little more dense or flimsy; but no
alteration in the size or quantity of loops can take place. Hence where
the manufacture is extensively prosecuted, many frames may be thrown
idle by every vicissitude of demand; and where a poor mechanic does
purchase his own frame, he is for ever limited to the same kind of work.
The gauge, as it is called, of a stocking-frame is regulated by the
number of loops contained in three inches of breadth, and varies very
much; the coarsest frames in common use being about what are termed
Fourteens, and the finest employed in great extent about Forties. The
needles are of iron wire, the manufacture of which is very simple; but
long practice in the art is found necessary before a needle-maker
acquires the dexterity which will enable him both to execute his work
well, and in sufficient quantity to render his labour productive.
[Illustration: 553]
The process of making the needles is as follows:--Good sound iron wire,
of a proper fineness, is to be selected; that which is liable to split
or splinter, either in filing, punching, or bending, being totally unfit
for the purpose. The wire is first to be cut into proper lengths,
according to the fineness of the frame for which the needles are
designed, coarse needles being considerably longer than fine ones. When
a sufficient number (generally some thousands) have been cut, the wire
must be softened as much as possible. This is done by laying them in
rows in a flat iron box, about an inch deep, with a close cover; the box
being filled with charcoal between the strata of wires. This box, being
placed upon a moderate fire, is gradually heated until both the wires
and charcoal have received a moderate red heat, because, were the heat
increased to what smiths term the white heat, the wire would be rendered
totally unfit for the subsequent processes which it has to undergo, both
in finishing and working. When the box has been sufficiently heated, it
may be taken from the fire, and placed among hot ashes, until both ashes
and box have gradually cooled; for the slower the wires cool, the softer
and easier wrought they will be. When perfectly cool, the next process
is to punch a longitudinal groove in the stem of every needle, which
receives the point or barb, when depressed. This is done by means of a
small engine worked by the power of a screw and lever. The construction
of these engines is various; but a profile elevation of one of the most
simple and commonly used will be found in _fig._ 553. It consists of two
very strong pieces of malleable iron, represented at A and C, and these
two pieces are connected by a strong well-fitted joint at B. The lower
piece, or sole of the engine at C, is screwed down by bolts to a strong
board or table, and the upper piece A will then rise or sink at
pleasure, upon the joint B. In order that A may be very steady in rising
and sinking, which is indispensable to its correct operation, a strong
bridle of iron, which is shewn in section E, is added to confine it, and
direct its motion. In the upper part of this bridle is a female screw,
through which the forcing screw passes, which is turned by the handle or
lever D. To the sole of the engine C is fixed a bolster of tempered
steel, with a small groove to receive the wire, which is to be punched;
and in the upper or moving part A, is a sharp chisel, which descends
exactly into the groove, when A is depressed by the screw. These are
represented at F, and above H. At G is a strong spring, which forces up
the chisel when the pressure of the screw is removed. The appearance of
the groove, when the punching is finished, will be rendered familiar by
inspecting _fig._ 554., p. 651. When the punching is finished, the wires
are to be brought to a fine smooth point by filing and burnishing, the
latter of which should be very completely done, as, besides polishing
the wire, it tends greatly to restore that spring and elasticity which
had been removed by the previous operation of softening. The wire is
next to be bent, in order to form the hook or barb; and this is done
with a small piece of tin plate bent double, which receives the point of
the wire, and by its breadth regulates the length of the barb. The stem
of the needle is now flattened with a small hammer, to prevent it from
turning in the tin socket in which it is afterwards to be cast; and the
point of the barb being a little curved by a pair of small plyers, the
needle is completed.
[Illustration: 554 555]
In order to fit the needles for the frame, they are now cast into the
tin sockets, or leads as they are called by the workmen; and this is
done by placing the needles in an iron mould, which opens and shuts by
means of a joint, and pouring in the tin while in a state of fusion. In
common operations, two needles are cast into the same socket. The form
of the needle, when complete and fitted to its place in the frame, will
be seen in _fig._ 555., which is a profile section of the needle-bar
exhibiting one needle. In this figure a section of the presser is
represented at F; the needle appears at G, and the socket or level at K.
At H, is a section of the needle-bar, on the fore part of which is a
small plate of iron called a verge, to regulate the position of the
needles. When placed upon the bar resting against the verge, another
plate of iron, generally lined with soft leather, is screwed down upon
the sockets or leads, in order to keep them all fast. This plate and the
screw appear at I. When the presser at F, is forced down upon the barb,
this sinks into the groove of the stem, and the needle is shut; when the
presser rises, the barb opens again by its own elasticity.
[Illustration: 556 557]
The needles or hooks being all properly fitted, the next part of the
stocking-frame to which attention ought to be paid, is the machinery for
forming the loops; and this consists of two parts. The first of these,
which sinks between every second or alternate needle, is represented at
O, _fig._ 552., and is one of the most important parts of the whole
machine. It consists of two moving parts; the first being a succession
of horizontal levers moving upon a common centre, and called jacks, a
term applied to vibrating levers in various kinds of machinery as well
as the stocking-frame. One only of these jacks can be represented in the
profile _fig._ 552.; but the whole are distinctly shown in a horizontal
position in _fig._ 556.; and a profile upon a very enlarged scale is
given in _fig._ 557. The jack shewn in _fig._ 552., extends
horizontally from O to I, and the centre of motion is at R. On the
front, or right hand part of the jack at O, is a joint suspending a very
thin plate of polished iron, which is termed a sinker. One of these
jacks and sinkers is allotted for every second or alternate needle. The
form of the sinker will appear at S, _fig._ 557.; and in order that all
may be exactly uniform in shape, they are cut out and finished between
two stout pieces of iron, which serve as moulds or gauges to direct the
frame-smith. The other end of the jack at I, is tapered to a point; and
when the jacks are in their horizontal position, they are secured by
small iron springs, one of which is represented at I, _fig._ 552., each
spring having a small obtuse angled notch to receive the point of the
jack, against which it presses by its own elasticity. In _fig._ 557. the
centre is at R; the pointed tail is omitted for want of room, the joint
is at O, and the throat of the sinker, which forms the loop, is at S.
The standards at R, upon which the jack moves, are called combs, and
consist of pieces of flat smooth brass, parallel to, and equidistant
from each other. The cross-bar R, which contains the whole, is of iron,
with a perpendicular edge or rim on each side, leaving a vacancy between
them, or a space to receive the bottom part or tails of the combs. The
combs are then placed in the bar, with a flat piece of brass called a
countercomb, between each, to ascertain and preserve their distances
from each other. These countercombs are exactly of the same shape as the
combs, but have no tails. When both combs and countercombs are placed in
the bar, it is luted with clay so as to form a mould, into which is
poured a sufficient quantity of melted tin. When the tin has had time to
cool, the countercombs having no tails are easily taken out, and the
combs remain well fastened and secured by the tin, which has been fused
entirely round them. Thus they form a succession of standards for the
jacks; and a hole being drilled through each jack and each comb, one
polished wire put through, serves as a common centre for the whole.
[Illustration: 558]
The jack sinkers being only used for every alternate or second needle,
in order to complete this part of the apparatus, a second set of sinkers
is employed. These are, in form and shape, every way the same as the
jack sinkers, but they are jointed at the top into pieces of tin, all of
which are screwed to the sinker bar H, _fig._ 552.; and thus a sinker of
each kind descends between the needles alternately. By these sinkers the
loops are formed upon all the needles, and the reason of two sets
different in operation being employed, will be assigned in describing
the mode of working the frame. The presser of the operation, of which
something has already been said, appears at F; and of the two arms which
support and give motion to it, one appears very plainly at E, its centre
of motion being at C. The circular bend given to these arms, besides
having an ornamental effect, is very useful, in order to prevent any
part from interfering with the other parts which are behind, by
elevating them entirely above them. The extremity of these arms at the
termination of the bends behind, are connected by a cross bar, which has
also a circular bend in the middle, projecting downwards, for a reason
similar to that already assigned. This bend is concealed in _fig._ 552.,
but visible in the front elevation, _fig._ 558. From the middle of the
bend, the presser is connected with the middle treadle by a depending
wire appearing at M, _fig._ 552., and thus, by the pressure of that
treadle, the presser is forced down to close the barbs of the needle.
The re-ascent of the presser is sometimes effected by means of a
counterpoising weight passing over a pulley behind; and sometimes by the
reaction of a wooden spring, formed of a strong hoop like that
represented at K. The latter of these is preferred, especially by the
Nottingham hosiers, because, as they assert, it makes the presser spring
up with greater rapidity, and consequently saves time in working. How
far this may be practically the case, it would be superfluous here to
investigate; but it is obvious that the wooden spring, if very stiff,
must add much to the hosier’s exertion of his foot, already exercised
against the united spring of all his barbs; and this inconvenience is
much complained of by those who have been accustomed to work with the
counterpoise.
[Illustration: 559 560 561]
At L are two pulleys or wheels, of different diameters, moving upon a
common centre, by which the jack sinkers are relieved from the back
springs, and thrown downwards to form the loops upon the needles. About
the larger wheel is a band of whipcord, passing twice round, the
extremities of which are attached to what is called the slur, which
disengages the jacks from the back springs. The smaller pulley, by
another band, communicates with the right and left treadle; so that
these treadles, when pressed alternately, turn the pulleys about in an
inverted order. The directions of these bands also appear more plainly
in the front elevation, _fig._ 558. The construction of the slur, and
its effect upon the jacks, will also be rendered apparent by _fig._ 559.
In this figure, eight jacks are represented in section, the tail part of
three of which, 1, 2, 3, are thrown up by the slur in its progress from
left to right; the fourth is in the act of rising, and the remaining
four, 5, 6, 7, and 8, are still unacted upon, the slur not yet having
reached them. As the slur acts in the direction of the dotted line X, X,
_fig._ 556., behind the centres of the jacks, it is hardly necessary to
remark, that this forcing up of the tails must of course depress the
joints by which the sinkers in front are suspended. The jack sinkers
falling successively from the loops on every alternate needle, in the
way represented at _fig._ 560., where both kinds of sinkers appear in
section, the light part expressing what is above the point at which the
throat of the sinker operates upon the thread, and the dark part what is
below. The second set, or, as they are called, the lead sinkers, from
the manner of jointing them, and suspending them from the bar above,
appear still elevated; the position of the bar being represented by the
line A, B. But when these are pulled down to the level of the former by
the operator’s hands, the whole looping will be completed, and the
thread C, D, which is still slack, will be brought to its full and
proper degree of tension, which is regulated by stop screws, so as to be
tempered or altered at pleasure. The sinking of this second set of
sinkers, may be easily explained by _fig._ 561. The direction of the
sinkers is expressed by the line E; the bar from which they are
suspended will be at A; the top frame is in the direction from A to B;
the back standards at D, and the joint at B, is the centre of motion. If
E is pulled perpendicularly downwards, the spring C, will be contracted,
and its upper extreme point G, will be brought nearer to its lower
extreme point F, which is fixed. Again, when the force which has
depressed E is removed, the spring C will revert to its former state,
and the sinkers will rise. The raising of the jack sinkers and jacks
takes place at the same time, by the hosier raising his hands; and for
the cause of this we must revert to _fig._ 556. The lead sinkers in
rising, lay hold of notches, which raise the extreme parts of the set of
jacks Z, Z, which are called half-jacks. Between the extremities of
these at Z, Z, is a cross bar, which, in descending, presses all the
intermediate jacks behind the common centre, and restores them to their
original posture, where they are secured by the back springs, until they
are again relieved by the operation of the slur recrossing at the next
course.
_Working of the frame._--In order to work a frame, the whole apparatus
being previously put into complete order, the hosier places himself on
the seat B in front, and provides himself with a bobbin of yarn or
stuff. This bobbin he places loosely on a vertical pin of wire, driven
into one side of the frame contiguous to the needles, so that it may
turn freely as the stuff is unwound from it. Taking the thread in his
hand, he draws it loosely along the needles, behind the barbs, and under
the throats of the sinkers. He then presses down one of the treadles to
pass the slur along, and unlock the jacks from the back springs, that
they may fall in succession. When this is done, the number of loops thus
formed is doubled by bringing down the lead sinkers, and the new formed
loops are lodged under the barbs of the needles by bringing forward the
sinkers. The preceding course, and former fabric, being then again
pushed back, the barbs are shut by depressing the middle treadle, and
forcing down the presser upon the needles. The former work is now easily
brought over the shut needles, after which, by raising the hands, both
sets of sinkers are raised; the jacks are locked by the back springs,
and the hosier goes on to another course.
From this it will be apparent, that the remark made in the outset is
well founded, that there are in reality, no complicated or difficult
movements in the stocking-frame. Almost the whole are merely those of
levers moving upon their respective fulcra, excepting that of the
carriage which gives the horizontal motion to the sinkers, and that is
merely an alternate motion on four wheels. Yet the frame is a machine
which requires considerable experience and care, both to work it to
advantage, and also to keep it in good order. This circumstance arises
greatly from the small compass in which a number of moving parts must be
included. Owing to this, the needles, unless cautiously and delicately
handled, are easily bent or injured. The same circumstance applies with
equal or greater force to the sinkers, which must be so very thin as to
be easily injured. But as these must work freely, both in a
perpendicular and horizontal direction between the needles, in a very
confined and limited space, the slightest variation in either, from
being truly and squarely placed, unavoidably injures the others. When a
hosier, either ignorant of the mechanical laws, of their relation to
each other, or too impatient to wait for the assistance of another,
attempts to rectify defects, he in most cases increases them tenfold,
and renders the machine incapable of working at all, until repaired by
some more experienced person. This circumstance has given rise to a set
of men employed in this trade, and distinguished by the name of
upsetters; and these people, beside setting new frames to work, have
frequently more employment in repairing old ones injured by want of care
or skill, than many country apothecaries, who live in unhealthy
parishes, find in tampering with the disorders of mankind.
It seems unnecessary to go further into detail respecting a machine so
well known, and which requires practical attention even more than most
others. It may, therefore, be sufficient to describe shortly some of its
varieties, the most simple and common of which is the rib
stocking-frame.
_Rib stocking-frame._--This frame, which, next to the common frame, is
most extensively in use, is employed for working those striped or ribbed
stockings, which are very common in all the different materials of which
hosiery is formed. In principle it does not differ from the common
frame, and not greatly in construction. The preceding general
description will nearly apply to this machine with equal propriety as to
the former: that part, however, by which the ribs or stripes are formed,
is entirely an addition, and to the application of this additional
machinery it may be proper to pay the chief attention, referring chiefly
to _fig._ 558., which is a front elevation.
[Illustration: 562]
This figure has been already referred to for the illustration of those
parts of the machinery which are common to both, and those parts
therefore require no recapitulation. The principle of weaving ribbed
hosiery possesses considerable affinity to that which subsists in the
weaving of that kind of cloth which is distinguished by the name of
tweeling, for the formation of stripes, with some variation arising
merely from the different nature of the fabric. In cloth weaving, two
different kinds of yarn intersecting each other at right angles, are
employed; in hosiery only one is used. In the tweeling of cloth, striped
as dimity, in the cotton or kerseymere, and in the woollen manufacture,
the stripes are produced by reversing these yarns. In hosiery, where
only one kind of yarn is used, a similar effect is produced by reversing
the loops. To effect this reversing of the loops, a second set of
needles is placed upon a vertical frame, so that the bends of the hooks
may be nearly under those of the common needles. These needles are cast
into tin moulds, pretty similar to the former, but more oblique or
bevelled towards the point, so as to prevent obstructions in working
them. They are also screwed to a bar of iron, generally lighter than the
other, and secured by means of plates: this bar is not fixed, but has a
pivot in each end, by means of which the bar may have a kind of
oscillatory motion on these pivots. Two frames of iron support this bar;
that in which it oscillates being nearly vertical, but inclined a little
towards the other needles. _Fig._ 562., which is a profile elevation,
will serve to illustrate the relative position of each bar to the other.
The lower or horizontal frame, the ends only of which can be seen in
_fig._ 558. under _a a_, appears in profile in _fig._ 562., where it is
distinguished by _d_. The vertical frame at _a_ is attached to this by
two centre screws, which serve as joints for it to move in. On the top
of this frame is the rib-needle bar at _f_, in _figs._ 552. and 562.,
and one needle is represented in _fig._ 562. at _f_. At _g_ is a small
presser, to shut the barbs of the rib-needles, in the same manner as the
large one does those of the frame. At _h_ is one of the frame needles,
to show the relative position of the one set to the other. The whole of
the rib-bar is not fitted with needles like the other; for here needles
are only placed where ribs or stripes are to be formed, the intervals
being filled up with blank leads, that is to say, with sockets of the
same shape as the others, but without needles; being merely designed to
fill the bar and preserve the intervals. Two small handles depend from
the needle bar, by which the oscillatory motion upon the upper centres
is given. The rising and sinking motion is communicated to this machine
by chains which are attached to iron sliders below, and which are
wrought by the hosier’s heel when necessary. The pressure takes place
partly by the action of the small presser, and partly by the motion of
the needles in descending, A small iron slider is placed behind the
rib-needles, which rises as they descend, and serves to free the loops
perfectly from each other.
In the weaving of ribbed hosiery, the plain and rib courses are wrought
alternately. When the plain are finished, the rib-needles are raised
between the others, but no additional stuff is supplied. The rib-needles
intersecting the plain ones, merely lay hold of the last thread, and, by
again bringing it through that which was on the rib-needle before, give
it an additional looping, which reverses the line of chaining, and
raises the rib above the plain intervals, which have only received a
single knitting.
[Illustration: 563]
HOT-FLUE, is the name given in England to an apartment heated by stoves
or steam pipes, in which padded and printed calicoes are dried hard.
_Fig._ 563. represents the simplest form of such a flue, heated by the
vertical round iron stove C, from whose top a wide square pipe proceeds
upwards in a slightly inclined direction, which receives the current of
air heated by the body and capital of the stove. In this wide channel
there are pullies, with cords or bands which, suspend by hooks, and
conduct the web of calico, from the entrance at B, where the operative
sits, to near the point A, and back again. This circuit may be repeated
once or oftener till the goods are perfectly dried. At D the driving
pulley connected with the main shaft is shown. Near the feet of the
operative is the _candroy_ or reel upon which the moist goods are rolled
in an endless web; so that their circulation in the hot-air channel can
be continued without interruption, as long as may be necessary.
[Illustration: 564]
_Fig._ 564. is a cross section of the apparatus of the regular hot-flue,
as it is mounted in the most scientific calico works of England, those
of James Thomson, Esq., of Primrose, near Clitheroe, Lancashire. _a a a
a_, is an arched apartment, nearly 30 yards long, by 13 feet high, and
10 feet wide. Through about one half of this gallery there is a
horizontal floor supported on arches, above which is the driest space,
through which the goods are finally passed before they escape from the
hot-flue, after they have been previously exposed to the hot but
somewhat moist air of the lower compartment. A large square flue covered
with cast-iron plates runs along the whole bottom of the gallery. It is
divided into two long parallel vaults, whose sections are seen at _u_,
_u_, _fig._ 564., covered with the cast-iron plates _v v_, grooved at
their ends into one another. The thickness of these plates is increased
progressively as they come nearer to the fireplace or furnace. There are
dampers which regulate the draught, and of course the heat of the stove.
_h h_ are the air-passages or vent-holes, left in the side walls, and
which by means of a long iron rod, mounted with iron plates, may be
opened or closed together to any degree. _k k_ are the cast-iron
supports of the tinned brass rollers which guide the goods along, and
which are fixed to the cross pieces represented by _r r_, _fig._ 564. _l
l_ are iron bars for supporting the ventilators or fans (see the fan
under FOUNDRY). These fans are here enclosed within a wire grating. They
make about 300 turns per minute, and expel the moist air with perfect
effect. _s_ indicates the position of the windows, which extend
throughout the length of the building. _t_ is a gas-light jet, placed at
the side of each window to supply illumination for night work.
The piece is stretched along the whole extent of the gallery, and runs
through it in the course of one minute and a half; being exposed during
its passage to the heat of 212° Fahr.
[Illustration: 565]
In _fig._ 565., A is the iron door of entrance to the hot-flue gallery;
at _b_ is the padding machine, where the goods are imbued with the
general mordant. The speed of this machine may be varied by means of the
two conical drums _c c_, which drive it; since when the band _c c_, is
brought by its forks, and adjusting screws, nearer to the narrow end of
the lower drum, the cylinder upon the same shaft with the latter is
driven quicker; and _vice versa_. Over D D the cords are shown for
drawing the drum mechanism into geer with the main shaft band F, F, E;
or for throwing it out of geer. The pullies F F carry the bands which
transmit the motion to the padding machine. A cylindrical drum exterior
to the hot-flue, covered with flannel, serves to receive the end of the
series of pieces, and to draw them through the apartment. This mode of
drying the padded calicoes requires for each piece of 28 yards, 3
pounds of coals for the furnace when a fan is employed, and 4 pounds
without it.
HYDRATES; are compounds of the oxides, salts, &c. with water in definite
or equivalent proportions. Thus slaked lime consists of one atom of
quick-lime = 28, + one atom of water = 9, of which the sum is 37 on the
hydrogen scale.
HYDRAULIC PRESS. See OIL, PRESS, and STEARINE.
HYDRIODIC ACID; (_Acide Hydriodique_, Fr.; _Hydriodsäure_, Germ.) is an
acid formed by the combination of 99·21 parts of iodine, and 0·79
hydrogen. When pure, it occurs in the gaseous state, but it combines
with water like the hydrochloric or muriatic acid gas into a liquid
acid.
HYDROCHLORIC ACID; the new chemical name of muriatic acid, which see.
HYDROGEN; (Eng. and Fr.; _Wasserstoff_, Germ.) an undecompounded gaseous
body; the lightest of all ponderable matter, whose examination belongs
to chemistry.
HYDROMETER; an instrument for ascertaining the specific gravities of
liquids. Baumé’s hydrometer, which is much used in France, and other
countries of the continent of Europe, when plunged in pure water, at the
temperature of 58° Fahr., marks 0 upon its scale; in a solution
containing 15 per cent. of common salt, (chloride of sodium) and 85 of
water by weight, it marks 15°; so that each degree is meant to indicate
a density corresponding to one per cent. of that salt. See AREOMETER,
for comparative tables of hydrometers.
HYDROSULPHURETS; chemical compounds of bases with sulphuretted hydrogen.
HYMENŒA COURBARIL; a tree growing in South America, from which the resin
_animé_ exudes.
HYOSCIAMUS NIGER. Henbane is a plant used in medicine, from which modern
chemistry has extracted a new crystalline vegetable principle called
_hyosciamine_, which is very poisonous, and when applied in solution to
the eye, determines a remarkable dilatation of the pupil; as
_belladonna_ also does.
HYPOSULPHATES; HYPOSULPHITES; saline compounds of the hyposulphuric or
hyposulphurous acid with bases.
HYPEROXYMURIATES; the old and incorrect name of CHLORATES.