For an assay of gold, 4_s._; for a parting assay of gold and silver,
6_s._; for a silver assay, 2_s._ 6_d._--charges which absorb the profits
of many a transaction.
The charges at the Royal Mint of Paris, for assays made under the
following distinguished chemical _savants_--Darcet, _Directeur_; Bréant,
_Verificateur_; Chevillot and Pelouze, _Essayeurs_; are--
For an assay of gold, or _doré_, (a parting assay,) 3 francs.
-- silver -- -- 0. 80 c. = 8_d._
English.
M. Gay Lussac is the assayer of the _Bureau de Garantie_ at the _Monnaie
Royale_, an office which corresponds to the Goldsmiths’ Hall at London.
The silver assays in all the official establishments of Europe, except
the two in London, are made by the _humid_ method, and are free from
those errors and blunders which daily annoy and despoil the British
bullion merchant, who is compelled by the Mint and Bank of England to
buy and sell by the _cupellation_ assay of Mr. Bingley. See ASSAY and
SILVER.
REFRIGERATION OF WORTS, &c. In August, 1826, Mr. Yandall obtained a
patent for an apparatus designed for cooling worts and other hot fluids,
without exposing them to evaporation. Utensils employed for this
purpose, are generally called refrigerators, and are so constructed,
that a quantity of cold water shall be brought in contact with the
vessel which contains the heated fluid. But in every construction of
refrigerator heretofore used, the quantity of cold water necessarily
employed in the operation, greatly exceeded the quantity of the fluid
cooled, which, in some situations, where water cannot be readily
obtained, was a serious impediment and objection to the use of such
apparatus.
The inventor has contrived a mode of constructing a refrigerator, so
that any quantity of wort or other hot fluid may be cooled by an equal
quantity of cool water; the process being performed with great
expedition, simply by passing the two fluids through very narrow
passages, in opposite directions, the result of which is, that the cold
liquor imbibes the heat from the wort, or other fluid, and the
temperature of the hot fluid is reduced in the same ratio.
[Illustration: 932 933 934]
_Figs._ 932, 933, and 934. represent different forms in which the
apparatus is proposed to be made. The two first have zigzag passages;
the third, channels running in convolute curves. These channels or
passages are of very small capacity in thickness, but of great length,
and of any breadth that may be required, according to the quantity of
fluid intended to be cooled or heated.
_Fig._ 935. is the section of a portion of the apparatus shown at
_figs._ 932. and 933. upon an enlarged scale; it is made by connecting
three sheets of copper or any other thin metallic plates together,
leaving parallel spaces between each plate for the passage of the
fluids, represented by the black lines.
These spaces are formed by occasionally introducing between the plates
thin straps, ribs, or portions of metal, by which means very thin
channels are produced, and through these channels the fluids are
intended to be passed, the cold liquor running in one direction, and the
hot in the reverse direction.
Supposing that the passages for the fluids are each one-eighth of an
inch thick, then the entire length for the run of the fluid should be
about 80 feet, the breadth of the apparatus being made according to the
quantity of fluid intended to be passed through it in a given time. If
the channels are made a quarter of an inch thick, then their length
should be extended to 160 feet; and any other dimensions in similar
proportions: but a larger channel than one quarter of an inch, the
patentee considers would be objectionable. It is, however, to be
observed, that the length here recommended, is under the consideration,
that the fluids are driven through the apparatus by some degree of
hydrostatic pressure from a head in the delivery-vats above; but if the
fluids flow without pressure, then the lengths of the passages need not
be quite so great.
[Illustration: 935]
In the apparatus constructed as shown in perspective at _fig._ 932., and
further developed by the section, _fig._ 935., cold water is to be
introduced at the funnel _a_, whence it passes down the pipe _b_, and
through a long slit or opening in the side of the pipe, into the passage
_c_, _c_ (see _fig._ 935.), between the plates, where it flows in a
horizontal direction through the channel towards the discharge-pipe _d_.
When such a quantity of cold water has passed through the funnel _a_, as
shall have filled the channel _c_, _c_, up to the level of the top of
the apparatus, the cock _e_ being shut, then the hot wort or liquor
intended to be cooled, may be introduced at the funnel _f_, and which,
descending in the pipe _g_, passes in a similar manner to the former,
through a long slit or opening in the side of the pipe _g_, into the
extended passage _h_, _h_ (see _fig._ 935.), and from thence proceeds
horizontally into the discharge-pipe _i_.
The two cocks _e_ and _k_, being now opened, the wort or other liquor is
drawn off, or otherwise conducted away through the cock _k_, and the
water through _e_. If the apertures of the two cocks _e_ and _k_, are
equal, and the channels equal also, it follows that the same quantity of
wort, &c., will flow through the channel _h_, _h_, _h_, in a given time,
as of water through the channel _c_, _c_; and by the hot fluid passing
through the apertures in contact with the side of the channel which
contains the cold fluid, the heat becomes abstracted from the former,
and communicated to the latter; and as the hot fluid enters the
apparatus at that part which is in immediate contact with the part where
the cooling fluid is discharged, and the cold fluid enters the apparatus
at that part where the wort is discharged, the consequence is, that the
wort or other hot liquor becomes cooled down towards its exit-pipe
nearly to the temperature of cold water; and the temperature of the
water, at the reverse end of the apparatus, becomes raised nearly to
that of the boiling wort.
It only remains to observe, that by partially closing either of the
exit-cocks, the quantity of heat abstracted from one fluid, and
communicated to the other, may be regulated; for instance, if the cock
_e_ of the water-passage be partially closed, so as to diminish the
quantity of cold water passed through the apparatus, the wort or other
hot fluid conducted through the other passages will be discharged at a
higher temperature, which in some cases will be desirable, when the
refrigerated liquor is to be fermented.
_Fig._ 933. exhibits an apparatus precisely similar to the foregoing,
but different in its position; for instance, the zigzag channels are
made in obliquely descending planes. _a_ is the funnel for the hot
liquor, whence it descends through the pipe _d_ into the channel _c_,
_c_ (see _fig._ 935.), and ultimately is discharged through the pipe
_b_, at the cock _e_. The cold water being introduced into the funnel
_f_, and passing down the pipe _i_, enters the zigzag channel _h_, _h_,
and, rising through the apparatus, runs off by the pipe _g_, and is
discharged at the cock below.
The passages of this apparatus for heating and cooling fluids, may be
bent into various contorted figures; one form found particularly
convenient under some applications, is that represented at _fig._ 934.,
which is contained in a cylindrical case. The passages here run in
convolute curves, the one winding in a spiral to the centre, the other
receding from the centre.
The wort or other hot liquor intended to be cooled, is to be introduced
at the funnel _a_, and passing down the pipe _b_, is delivered into the
open passage _c_, which winds round to the central chamber _d_, and is
thence discharged through the pipe _e_, at the cock _f_. The cold water
enters the apparatus at the funnel _g_, and proceeding down the pipe
_h_, enters the closed channel _i_, and after traversing round through
the apparatus, is in like manner discharged through the pipe _k_, at the
cock _l_. Or the hot liquor may be passed through the closed channel,
and the cold through the open one; or these chambers may be both of them
open at top, and the apparatus covered by a lid when at work, the
principal design of which is to afford the convenience of cleaning them
more readily than could be done if they were closed; or they may be both
closed.
A similar ingenious apparatus for cooling brewers’ worts, or wash for
distillers, and also for condensing spirits in place of the ordinary
worm tub, is called by the inventor, Mr. Wheeler, an Archimedes
condenser, or refrigerator, the peculiar novelty of which consists in
forming the chambers for the passage of the fluids in spiral channels,
winding round a central tube, through which spiral channels the hot and
cold fluids are to be passed in opposite directions.
[Illustration: 936 937 938]
_Fig._ 936. represents the external appearance of the refrigerator,
enclosed in a cylindrical case; _fig._ 937., the same, one-half of the
case being removed to show the form of the apparatus within; and _fig._
938., a section cut through the middle of the apparatus perpendicularly,
for the purpose of displaying the internal figure of the spiral
channels.
The apparatus is proposed to be made of sheet copper, tinned on its
surface, and is formed by cutting circular pieces of thin copper, or
segments of circles, and connecting them together by rivets, solder, or
by any other convenient means, as coppersmiths usually do; these
circular pieces of copper being united to one another, in the way of a
spiral or screw, form the chambers through which the fluids are to pass
within, in an ascending or descending inclined plane.
In _figs._ 937. and 938., _a_, _a_, is the central tube or standard (of
any diameter that may be found convenient), round which the spiral
chambers are to be formed; _b_, _b_, are the sides of the outer case, to
which the edges of the spiral fit closely, but need not be attached;
_c_, _c_, are two of the circular plates of copper, connected together
by rivets at the edges, in the manner shown, or by any other suitable
means; _d_, is the chamber, formed by the two sheets of copper, and
which is carried round from top to bottom in a spiral or circular
inclined plane, by a succession of circular plates connected to each
other.
The hot fluid is admitted into the spiral chamber _d_, through a trumpet
or wide-mouthed tube _e_, at top, and is discharged at bottom by an
aperture and cock _f_. The cold water which is to be employed as the
cooling material, is to be introduced through the pipe _g_, in the
centre, from whence discharging itself by a hole at bottom, the cold
water occupies the interior of the cylindrical case _b_, and rises in
the spiral passage _h_, between the coils of the chamber, until it
ascends to the top of the vessel, and then it flows away by a spout _i_,
seen in _fig._ 936.
It will be perceived that the hot fluid enters the apparatus at top, and
the cold fluid at bottom, passing each other, by means of which an
interchange of temperatures takes place through the plates of copper,
the cooling fluid passing off at top in a heated state, by means of the
caloric which it has abstracted from the hot fluid; and the hot fluid
passing off through the pipe and cock at bottom, in a very reduced state
of temperature, by reason of the caloric which it held having been given
out to the cooling fluid.
[Illustration: 939 940]
_Fig._ 939. is a side view and section of Wagenmann’s apparatus for
cooling worts; _fig._ 940., a view from above. The preceding
contrivances seem to be far preferable.
_a_, _a_, is the tub for receiving the apparatus, whose central upright
shaft _b_, rests upon a step _c_, in the bottom, and revolves at top in
a bush at _d_, made fast to a bar _e_, fixed flat across the mouth of
the tub. The shaft may be driven by the two bevel wheels _f_, _f_, at
right angles to each other, and the horizontal rod turned by hand; or
the whole may be impelled by any power. _g_, is an iron basin for
receiving the cold water from the spout _h_, supplied by a well; it
flows out of the basin through two tubes _i i_, down into the lower part
of the cooler _k k_. The cooler consists of two flat vessels, both of
which are formed of a flat interior plate, and an arched exterior one,
so that their transverse section is plano-convex. The water which flows
along the tubes _i i_, spreads itself upon the bottom of the cooler, and
then rises through the scabbard-shaped tubes _l l_, &c., into the upper
annular vessel _m m_; whence it is urged by hydrostatic pressure, in a
now heated state, through the slanting tubes _n n_, which terminate in
the common pipe _o_, of the annular basin _p p_, and is thence
discharged by the pipe _q_. The basin _p p_, is supported by the two
bearers _r_, made fast to the cross-beam _e_. There is in the lowest
part of the hollow ring at bottom, a screw plug, which may be opened
when it is desired to discharge the whole contents, and to wash it with
a stream of water.
REGULUS, is a term introduced, by the alchemists, now nearly obsolete.
It means literally a little king, and refers to the metallic state as
one of royalty, compared with the native earthy condition. Antimony is
the only metal now known by the name of regulus.
RESINS (_Résines_, Fr.; _Harze_, Germ.); are proximate principles found
in most vegetables, and in almost every part of them; but the only
resins which merit a particular description, are those which occur
naturally in such quantities as to be easily collected or extracted.
They are obtained chiefly in two ways, either by spontaneous exudation
from the plants, or by extraction by heat and alcohol. In the first
case, the discharge of resin in the liquid state is sometimes promoted
by artificial incisions made in summer through the bark into the wood of
the tree.
Resins possess the following general properties:--They are soluble in
alcohol, insoluble in water, and melt by the application of heat, but do
not volatilize without partial decomposition. They have rarely a
crystalline structure, but, like gums, they seldom affect any peculiar
form. They are almost all translucid, not often colourless, but
generally brown, occasionally red or green. Any remarkable taste or
smell, which they sometimes possess, may be ascribed to some foreign
matter, commonly an essential oil. Their specific gravity varies from
0·92 to 1·2. Their consistence is also very variable. The greater part
are hard, with a vitreous fracture, and so brittle as to be readily
pulverized in the cold. Some of them are soft, a circumstance probably
dependent upon the presence of a heterogeneous substance. The hard
resins do not conduct electricity, and they become negatively electrical
by friction. When heated, they melt more or less easily into a thick
viscid liquid, and concrete, on cooling, into a smooth shining mass, of
a vitreous fracture, which occasionally flies off into pieces, like
Prince Rupert’s drops; especially after being quickly cooled, and
scratched with a sharp point. They take fire by contact of an ignited
body, and burn with a bright flame, and the diffusion of much sooty
smoke. When distilled by themselves in close vessels, they afford
carbonic acid and carburetted gases, empyreumatic oil of a less
disagreeable smell than that emitted by other such oils, a little
acidulous water, and a very little shining charcoal. See ROSIN GAS.
Resins are insoluble in water, but dissolve in considerable quantities
in alcohol, both hot and cold. This solution reddens tincture of litmus,
but not syrup of violets; it is decomposed by water, and a milkiness
ensues, out of which the particles of the resin gradually agglomerate.
In this state it contains water, so as to be soft, and easily kneaded
between the fingers; but it becomes hard and brittle again when freed by
fusion from the water. The resins dissolve in ether and the volatile
oils, and, with the aid of heat, combine with the unctuous oils. They
may be combined by fusion with sulphur, and with a little phosphorus.
Chlorine water bleaches several coloured resins, if they be diffused in
a milky state through water. The carburet of sulphur dissolves them.
Resins are little acted upon by acids, except by the nitric, which
converts them into artificial tan. They combine readily with the alkalis
and alkaline earths, and form what were formerly reckoned soaps: but the
resins are not truly saponified; they rather represent the acid
constitution themselves, and, as such, saturate the salifiable bases.
Every resin is a natural mixture of several other resins, as is the case
also with oils; one principle being soluble in cold alcohol, another in
hot, a third in ether, a fourth in oil of turpentine, a fifth in
naphtha, &c. The soft resins, which retain a certain portion of volatile
oil, constitute what are called balsams. Certain other balsams contain
benzoic acid. The solid resins are, _amber_, _animé_, _benzoin_,
_colophony_ (common rosin), _copal_, _dammara_, _dragon’s blood_,
_elemi_, _guaiac_, _lac_, resin of _jalap_, _ladanum_, _mastic_,
_sandarach_, _storax_, _takamahac_.
RESIN, KAURI or COWDEE, is a new and very peculiar substance, recently
imported in considerable quantities from New Zealand, which promises to
be useful in the arts. It oozes from the trunk of a noble tree called
_Dammara australis_, or _Pinus kauri_, which rises sometimes to the
height of 90 feet without a branch, with a diameter of 12 feet, and
furnishes a log of heart timber of 11 feet. The resin, which is called
Cowdee gum by the importers, is brought to us in pieces varying in size
from that of a nutmeg to a block of 2 or 3 cwts. The colour varies from
milk-white to amber, or even deep brown; some pieces are transparent and
colourless. In hardness it is intermediate between copal and resin. The
white milky pieces are somewhat fragrant, like elemi. Specific gravity,
1·04 to 1·06. It is very inflammable, burns all away with a clear bright
flame, but does not drop. When cautiously fused, it concretes into a
transparent hard tough mass, like shellac. It affords a fine varnish
with alcohol, being harder and less coloured than mastic, while it is as
soluble, and may be had probably at one-tenth of the price. A solution
in alcohol, mixed with one-fourth of its bulk of a solution in oil of
turpentine, forms an excellent varnish, which dries quickly, is quite
colourless, clear, and hard. It is insoluble in pyro-acetic (pyroxilic?)
spirit. Combined with shellac and turpentine, it forms a good
sealing-wax.
REVERBERATORY FURNACE; see COPPER, IRON, and SODA.
RETORT. For producing coal gas, there are many modifications, varying in
dimension and shape with the caprice of the constructor, and in many
cases, without any definite idea of the principle to be aimed at.
They may be divided into three general classes:
1st. The circular retort, from twelve to twenty inches in diameter, and
from six to nine feet in length. This retort is used in Manchester and
some other places, in general for the distillation of cannel, or Scotch
parrot coal. It answers for the distillation of a coal which retains its
form in lumps, and is advantageous only from the facility with which its
position is changed, when partially destroyed by the action of fire on
the under side.
2nd. The small or London D retort, so called in consequence of its
having first been used by the chartered company in London, being still
in use at their works, and recommended by their engineer. This retort
is 12 inches broad on the base, 11 inches high, and 7 feet long,
carbonizing one and a half to two bushels at a charge.
3rd. The York D retort, (so called in consequence of its having been
introduced by Mr. Outhit, of York,) and the modifications of it, among
which I should include the elliptic retort, as having the same general
purpose in view. The difference between the London and York D retorts,
consists only in an extension of surface upon which the coal is spread.
See GAS-LIGHT.
RHODIUM, is a metal discovered by Dr. Wollaston in 1803, in the ore of
platinum. It is contained to the amount of three per cent. in the
platinum ore of Antioquia in Colombia, near Barbacoas; it occurs in the
Ural ore, and, alloyed with gold, in Mexico. The palladium having been
precipitated from the muriatic solution of the platinum ore previously
saturated with soda, by the cyanide of mercury, muriatic acid is to be
poured into the residuary liquid, and the mixture is to be evaporated to
dryness, to expel the hydrocyanic acid, and convert the metallic salts
into chlorides. The dry mass is to be reduced to a very fine powder, and
washed with alcohol of specific gravity 0·837. This solvent takes
possession of the double chlorides which the sodium forms with the
platinum, iridium, copper, and mercury, and does not dissolve the double
chloride of rhodium and sodium, but leaves it in the form of a powder,
of a fine dark-red colour. This salt being washed with alcohol, and then
exposed to a very strong heat, affords the rhodium. But a better mode of
reducing the metal upon the small scale, consists in heating the double
chloride gently in a glass tube, while a stream of hydrogen passes over
it, and then to wash away the chloride of sodium with water.
Rhodium resembles platinum in appearance. Any heat which can be produced
in a chemical furnace is incapable of fusing it; and the only way of
giving it cohesive solidity, is to calcine the sulphuret or arseniuret
of rhodium in an open vessel at a white heat, till all the sulphur or
arsenic be expelled. A button may thus be obtained, somewhat spongy,
having the colour and lustre of silver. According to Wollaston, the
specific gravity of rhodium is 11. It is insoluble by itself in any
acid; but when an alloy of it with certain metals, as platinum, copper,
bismuth, or lead, is treated with aqua regia, the rhodium dissolves
along with the other metals; but when alloyed with gold or silver, it
will not dissolve along with them. It may, however, be rendered very
soluble by mixing it in the state of a fine powder with chloride of
potassium or sodium, and heating the mixture to a dull-red heat, in a
stream of chlorine gas. It thus forms a triple salt, very soluble in
water. The solutions of rhodium are of a beautiful rose colour, whence
its name. In the dry way, it dissolves by heat in bisulphate of potassa;
and disengages sulphurous acid gas in the act of solution. There are two
oxides of rhodium. Rhodium combines with almost all the metals; and, in
small quantity, melted with steel, it has been supposed to improve the
hardness, closeness, and toughness of this metal. Its chief use at
present is for making the inalterable nibs of the so-named rhodium pens.
RIBBON MANUFACTURE, is a modification of WEAVING, which see.
RICE, of Carolina, analyzed by Braconnot, was found to be composed of
starch 85·07, of gluten 3·60, of gum 0·71, of uncrystallizable sugar
0·29, of a colourless rancid fat like suet 0·13, of vegetable fibre 4·8,
of salts with potash and lime bases 0·4, and 5·0 of water.
The quantity of rice entered for home consumption in the year 1836,
was--
Cwts. 81,610. In 1837, 126,739.
Ditto in the husk, Bushels 292,444. 282,377.
_Rice Paper_, as it is called, on which the Chinese and Hindoos paint
flowers so prettily, is a membrane of the bread-fruit tree, the
_Artocarpus incisifolia_ of naturalists.
RICE CLEANING. Various machines have been contrived for effecting this
purpose, of which the following, secured by patent to Mr. Melvil Wilson,
in 1826, may be regarded as a good specimen. It consists of an oblong
hollow cylinder, laid in an inclined position, having a great many teeth
stuck in its internal surface, and a central shaft also furnished with
teeth. By the rapid revolution of the shaft, its teeth are carried
across the intervals of those of the cylinder with the effect of parting
the grains of rice, and detaching whatever husks or impurities may
adhere to them. A hopper is set above to receive the rice, and conduct
it down into the cleansing cylinder.
About 80 teeth are supposed to be set in the cylinder, projecting so as
to reach very nearly the central shaft; in which there is a
corresponding number of teeth, that pass freely between the former.
The cylinder is shown inclined in the figure which accompanies the
specification; but it may be placed also upright or horizontal, and may
be mounted in any convenient frame-work. The central shaft should be put
in rapid rotation, while the cylinder receives a slow motion in the
opposite direction. The rice, as cleaned by that action, is discharged
at the lower end of the cylinder, where it falls into a shute (shoot),
and is conducted to the ground. The machine may be driven by hand, or by
any other convenient power.
Rice consists chiefly of starch, and therefore cannot by itself make a
proper bread. It is used in the cotton factories to form weavers’
dressings for warps. The Chinese reduce its flour into a pulp with hot
water, and mould it into figures and plates, which they afterwards
harden, and ornament with engravings, resembling those of
mother-of-pearl. When a decoction of rice is fermented and distilled, it
affords the sort of ardent spirit called _arrack_ in the East Indies.
RIFLE; see FIRE ARMS.
[Illustration: 941]
RINSING MACHINE, is one of those ingenious automatic contrivances for
economizing labour, and securing uniformity of action, now so common in
the factories of Lancashire. _Fig._ 941. is a longitudinal middle
section of an approved mechanism for rinsing pieces of calico dyed with
spirit or fancy colours, and which require more delicate treatment than
is compatible with hand-washing. A, E, F, B, is a wooden cistern, about
12 feet long, 4 feet high at one end, 2 feet at the other, and of the
ordinary width of calico cloth. It is divided transversely into a series
of equal compartments by partitions, decreasing in height from the upper
to the lower end, the top of each of them, however, being an inch at
least under the top of the enclosing side at its line of junction. Above
the highest end of the trough, a pair of squeezing rollers is mounted at
B; the lower one having a pulley upon the end of its shaft, for turning
it, by means of a band from one of the driving-shafts of the factory;
and the upper one is pressed down upon it by weighted levers acting on
the ends of its axis. The roller above the second highest partition has
also a pair of squeezing rollers, with a weighted lever D. The pieces of
cloth, stitched endwise, being laid upon a platform to the right hand of
the cistern, are introduced over the roller A, passed down under the
roller beneath it, and so up and down in a serpent-like path, from the
lowest compartment of the cistern to the uppermost, being drawn through
the series by the traction of the rotatory roller at B. While the long
web is thus proceeding upwards from A to B, a stream of pure water is
made to flow along in the opposite direction from B to A, running over
the top of each partition in a thin sheet. By this contrivance, the
goods which enter at A, having much loose colour upon their surface,
impregnate the water strongly, but as they advance they continually get
cleaner by the immersion, and pressure of the successive rollers, being
exposed to purer water, till at last they reach the limpid stream, and
are discharged at B perfectly bright. The rinsing operation may be
modified by varying the quantity of water admitted, the speed with which
the pieces are drawn through the cells, or the pressure upon the series
of top rollers.
ROCKETS. M. de Montgery, captain of a frigate in the French service, has
written a _Traité sur les Fusées de Guerre_, in which he discusses the
merits of the Congreve rockets, and describes methods of imitating them.
As the subject of military projectiles is foreign to this Dictionary, I
refer my readers to the above work, which is commended by the editor of
the _Dictionnaire Technologique_.
ROLLING-MILL. See IRON, MINT, and PLATED MANUFACTURE.
ROPE-MAKING. The fibres of hemp which compose a rope, seldom exceed in
length three feet and a half, at an average. They must, therefore, be
twined together so as to unite them into one; and this union is effected
by the mutual circumtorsion of the two fibres. If the compression
thereby produced be too great, the strength of the fibres at the points
where they join will be diminished; so that it becomes a matter of great
consequence to give them only such a degree of twist as is essential to
their union.
The first part of the process of rope-making by hand, is that of
spinning the yarns or threads, which is done in a manner analogous to
that of ordinary spinning. The spinner carries a bundle of dressed hemp
round his waist; the two ends of the bundle being assembled in front.
Having drawn out a proper number of fibres with his hand, he twists them
with his fingers, and fixing this twisted part to the hook of a whirl,
which is driven by a wheel put in motion by an assistant, he walks
backwards down the rope walk, the twisted part always serving to draw
out more fibres from the bundle round his waist, as in the flax-spinning
wheel. The spinner takes care that these fibres are equably supplied,
and that they always enter the twisted parts by their ends, and never by
their middle. As soon as he has reached the termination of the walk, a
second spinner takes the yarn off the whirl, and gives it to another
person to put upon a reel, while he himself attaches his own hemp to the
whirl hook, and proceeds down the walk. When the person at the reel
begins to turn, the first spinner, who has completed his yarn, holds it
firmly at the end, and advances slowly up the walk, while the reel is
turning, keeping it equally tight all the way, till he reaches the reel,
where he waits till the second spinner takes his yarn off the whirl
hook, and joins it to the end of that of the first spinner, in order
that it may follow it on the reel.
The next part of the process previous to tarring, is that of warping the
yarns, or stretching them all to one length, which is about 200 fathoms
in full-length rope-grounds, and also in putting a slight turn or twist
into them.
The third process in rope-making, is the tarring of the yarn. Sometimes
the yarns are made to wind off one reel, and, having passed through a
vessel of hot tar, are wound upon another, the superfluous tar being
removed by causing the yarn to pass through a hole surrounded with
spongy oakum; but the ordinary method is to tar it in skains or hanks,
which are drawn by a capstan with a uniform motion through the
tar-kettle. In this process, great care must be taken that the tar is
boiling neither too fast nor too slow. Yarn for cables requires more tar
than for hawser-laid ropes; and for standing and running rigging, it
requires to be merely well covered. Tarred cordage has been found to be
weaker than what is untarred, when it is new; but the tarred rope is not
so easily injured by immersion in water.
The last part of the process of rope-making, is to lay the cordage. For
this purpose two or more yarns are attached at one end to a hook. The
hook is then turned the contrary way from the twist of the individual
yarn, and thus forms what is called a strand. Three strands, sometimes
four, besides a central one, are then stretched at length, and attached
at one end to three contiguous but separate hooks, but at the other end
to a single hook; and the process of combining them together, which is
effected by turning the single book in a direction contrary to that of
the other three, consists in so regulating the progress of the twists of
the strands round their common axis, that the three strands receive
separately at their opposite ends just as much twist as is taken out of
them by their twisting the contrary way, in the process of combination.
Large ropes are distinguished into two main classes, the _cable-laid_
and _hawser-laid_. The former are composed of nine strands, namely,
three great strands, each of these consisting of three smaller secondary
strands, which are individually formed with an equal number of primitive
yarns. A cable-laid rope eight inches in circumference, is made up of
333 yarns or threads, equally divided among the nine secondary strands.
A _hawser-laid_ rope consists of only three strands, each composed of a
number of primitive yarns, proportioned to the size of the rope; for
example, if it be eight inches in circumference, it may have 414 yarns,
equally divided among three strands. Thirty fathoms of yarn are reckoned
equivalent in length to eighteen fathoms of rope cable-laid, and to
twenty fathoms hawser-laid. Ropes of from one inch to two inches and a
half in circumference are usually hawser-laid; of from three to ten
inches, are either hawser or cable laid; but when more than ten inches,
they are always cable-laid.
Every hand-spinner in the dock-yard is required to spin, out of the best
hemp, six threads, each 160 fathoms long, for a quarter of a day’s work.
A hawl of yarn, in the warping process, contains 336 threads.
The following are Captain Huddart’s improved principles of the rope
manufacture:--
1. To keep the yarns separate from each other, and to draw them from
bobbins revolving upon skewers, so as to maintain the twist while the
strand or primary cord is forming.
2. To pass them through a register, which divides them by circular
shells of holes; the number in each concave shell being conformable to
the distance from the centre of the strand, and the angle which the
yarns make with a line parallel to it, and which gives them a proper
position to enter.
3. To employ a tube for compressing the strand, and preserving the
cylindrical figure of its surface.
4. To use a gauge for determining the angle which the yarns in the
outside shell make with a line parallel to the centre of the strand,
when registering; because according to the angle made by the yarns in
this shell, the relative lengths of all the yarns in the strand will be
determined.
5. To harden up the strand, and thereby increase the angle in the
outside shell; which compensates for the stretching of the yarns, and
the compression of the strands.
A great many patents have been obtained, and worked with various degrees
of success, for making ropes. Messrs. Cartwright, Fothergill, Curr,
Chapman, Balfour, and Huddart, have been the most conspicuous inventors
in this country; but the limits of this work preclude us doing justice
to their respective merits.
All improvements in the manufacture of cordage at present in use, either
in her Majesty’s yards or in private rope-grounds, owe their superiority
over the old method of making cordage to Captain Huddart’s invention of
the register plate and tube.
Mr. Balfour took out a patent for the manufacture of cordage about a
month before Captain Huddart; but the formation of his strand was to be
accomplished by what he called a top minor, (in the form of a common
top, with pins to divide the yarns,) which upon trial could not make
cordage so good as by the common mode. On seeing Captain Huddart’s
specification, Mr. Balfour, five years after, procured another patent,
in which he included a plate and tube, but which was not sufficiently
correct, and experience in the navy proved the insufficiency of the
cordage. Captain Huddart’s plate and tube were then adopted in the
king’s yards, and he gave his assistance for the purpose.
Captain Huddart then invented and took a patent for a machine, which by
registering the strand at a short length from the tube, and winding it
up as made, preserved an uniformity of twist, or angle of formation,
from end to end of the rope, which cannot be accomplished by the method
of forming the strands down the ground, where the twist is communicated
from one end to the other of an elastic body upwards of 300 yards in
length. This registering-machine was constructed with such correctness,
that when some were afterwards required, no alteration could be made
with advantage by the most skilful and scientific mechanic of that day,
Mr. Rennie. Thus the cold register was carried to the greatest
perfection.
A number of yarns cannot be put together in a cold state, without
considerable vacancies, into which water may gain admission; Captain
Huddart, therefore, formed the yarns into a strand immediately as they
came from the tar-kettle, which he was enabled to do by his
registering-machine, and the result was most satisfactory. This
combination of yarns was found by experiment to be 14 per cent. stronger
than the cold register; it constituted a body of hemp and tar impervious
to water, and had great advantage over any other cordage, particularly
for shrouds, as after they were settled on the mast-head, and properly
set up, they had scarcely any tendency to stretch, effectually secured
the mast, and enabled the ship to carry the greatest press of sail.
In order more effectually to obtain correctness in the formation of
cables and large cordage, Captain Huddart constructed a laying-machine,
which has carried his inventions in rope-making to the greatest
perfection, and which, founded on true mathematical principles, and the
most laborious calculations, is one of the noblest monuments of
mechanical ability since the improvement of the steam-engine by Mr.
Watt. By this machine, the strands receive that degree of twist only
which is necessary, and are laid at any angle with the greatest
regularity; the pressure is regulated to give the required elasticity,
and all parts of the rope are made to bear equally. In no one instance
has a rope or cable thus formed, been found defective in the lay, or
stiff, or difficult to coil.
Such a revolution in the manufacture of cordage could not be
accomplished without great expense, as the works at Limehouse fully
testify; and considerable opposition necessarily arose. Captain
Huddart’s first invention was, however, generally adopted, as soon as
the patent expired; and experience has established the great importance
of his subsequent improvements.
His cordage has been supplied in large quantities to her Majesty’s navy,
and has received the most satisfactory reports.
The following description of one of the best modern machines for making
ropes on Captain Huddart’s plan, will gratify the intelligent reader.
[Illustration: 942]
_Fig._ 942. exhibits a side elevation of the tackle-board and
bobbin-frame at the head of the ropery, and also of the carriage or
rope-machine in the act of hauling out and twisting the strands.
[Illustration: 943 944 945 946]
_Fig._ 943. is a front elevation of the carriage.
_Fig._ 944. is a yarn-guide, or board, or plate, with perforated holes
for the yarns to pass through before entering the nipper.
_Figs._ 945. and 946. are side and front views of the nipper for
pressing the rope-yarns.
_a_ is the frame for containing the yarn bobbins. The yarns are brought
from the frame, and pass through a yarn-guide at _b_. _c_ is a small
roller, under which the rope-yarns pass; they are then brought over the
reel _d_, and through another yarn-guide _e_, after which they enter the
nippers at _v_, and are drawn out and formed into strands by the
carriage. The roller and reel may be made to traverse up and down, so as
to regulate the motion of the yarns.
The carriage runs on a railway. _f_, _f_, is the frame of the carriage;
_g_, _g_, are the small wheels on which it is supported; _k_, _k_, is an
endless rope, reaching from the head to the bottom of the railway, and
is driven by a steam-engine; _m_, _m_, is a wheel with gubs at the back
of it, over which the endless rope passes, and gives motion to the
machinery of the carriage. _n_, is the ground rope for taking out the
carriage, as will be afterwards described. On the shaft of _m_, _m_, are
two bevel wheels 3, 3, with a shifting catch between them; these bevel
wheels are loose upon the shaft, but when the catch is put into either
of them, this last then keeps motion with the shaft, while the other
runs loose. One of these wheels serves to communicate the twist to the
strand in drawing out; the other gives the opposite or after turn to the
rope in closing. 4, 4, is a lever for shifting the catch accordingly. 5,
is a third bevel wheel, which receives its motion from either of the
other two, and communicates the same to the two spur wheels 6, 6, by
means of the shaft _x_. These can be shifted at pleasure; so that by
applying wheels of a greater or less number of teeth above and beneath,
the twist given to the strands can be increased or diminished
accordingly. The upper of these two communicates motion, by means of the
shaft _o_, to another spur wheel 8, which working in the three pinions
above, 9, 9, gives the twist to the strand hooks.
The carriage is drawn out in the following manner. On the end of the
shaft of _m_, _m_, is the pinion 3, which, working in the large wheel R,
gives motion to the ground-rope shaft upon its axis. In the centre of
this shaft is a curved pulley or drum _t_, round which the ground rope
takes one turn. This rope is fixed at the head and foot of the ropery;
so that when the machinery of the carriage is set a-going by the endless
rope _k_, _k_, and gives motion to the ground-rope shaft, as above
described, the carriage will necessarily move along the railway; and the
speed may be regulated either by the diameter of the circle formed by
the gubs on the wheel _m_, _m_, or by the number of teeth in the pinion
3. At T, is a small roller, merely for preventing the ground rope from
coming up among the machinery. At the head of the railway, and under the
tackle-board, is a wheel and pinion Z, with a crank for tightening the
ground rope. The fixed machinery at the head, for hardening or tempering
the strands, is similar to that on the carriage, with the exception of
the ground-rope geer, which is unnecessary. The motion is communicated
by another endless rope, (or short band, as it is called, to distinguish
it from the other,) which passes over gubs at the back of the wheel 1,
1.
When the strands are drawn out by the carriage to the requisite length,
the spur wheels 3, R, are put out of geer. The strands are cut at the
tackle-board, and fixed to the hooks 1, 1, 1; after which they are
hardened or tempered, being twisted at both ends. When this operation is
finished, three strands are united on the large hook _h_, the top put
in, and the rope finished in the usual way.
In preparing the hemp for spinning an ordinary thread or rope-yarn, it
is only heckled over a large keg or clearer, until the fibres are
straightened and separated, so as to run freely in the spinning. In this
case, the hemp is not stript of the tow, or cropt, unless it is designed
to spin beneath the usual grist, which is about 20 yarns for the strand
of a three-inch strap-laid rope. The spinning is still performed by
hand, being found not only to be more economical, but also to make a
smoother thread, than has yet been effected by machinery. Various ways
have been tried for preparing the yarns for tarring. That which seems
now to be most generally in use, is, to warp the yarns upon the stretch
as they are spun. This is accomplished by having a wheel at the foot, as
well as the head of the walk, so that the men are able to spin both up
and down, and also to splice their threads at both ends. By this means,
they are formed into a haul, resembling the warp of a common web, and a
little turn is hove into the haul, to preserve it from getting foul in
the tarring. The advantages of warping from the spinners, as above,
instead of winding on winches, as formerly, are, 1st, the saving of this
last operation altogether; 2dly, the complete check which the foreman
has of the quantity of yarn spun in the day; 3dly, that the quality of
the work can be subjected to the minutest inspection at any time. In
tarring the yarn, it is found favourable to the fairness of the strip,
to allow it to pass around or under a reel or roller in the bottom of
the kettle while boiling, instead of coiling the yarn in by hand. The
tar is then pressed from the yarn, by means of a sliding nipper, with a
lever over the upper part, and to the end of which the necessary weight
is suspended. The usual proportion of tar in ordinary ropes, is
something less than a fifth. In large strap-laid ropes, which are
necessarily subjected to a greater press in the laying of them, the
quantity of tar can scarcely exceed a sixth, without injuring the
appearance of the rope when laid.
For a long period, the manner of laying the yarns into ropes, was by
stretching the haul on the rope-ground, parting the number of yarns
required for each strand, and twisting the strands at both ends, by
means of hand-hooks, or cranks. It will be obvious that this method,
especially in ropes of any considerable size, is attended with serious
disadvantages. The strand must always be very uneven; but the principal
disadvantage, and that which gave rise to the many attempts at
improvement, was, that the yarns being all of the same length before
being twisted, it followed, when the rope was finished, that while those
which occupied the circumference of the strand were perfectly tight, the
centre yarns, on the other hand, as they were now greatly slackened by
the operation of hardening or twisting the strands, actually would bear
little or no part of the strain when the rope was stretched, until the
former gave way. The method displayed in the preceding figures and
description, is among the latest and most improved; Every yarn is given
out from the bobbin frame as it is required in twisting the rope; and
the twist communicated in the out-going of the carriage, can be
increased or diminished at pleasure. In order to obtain a smooth and
well-filled strand, it is necessary also, in passing the yarns through
the upper board, to proportion the number of centre to that of outside
yarns. In ordinary sized ropes, the strand seems to have the fairest
appearance, when the outside yarns form from 2/3ds to 3/4ths of the
whole quantity, in the portion of twist given by the carriage in drawing
out and forming the strands.
[Illustration: 947 948 949]
In laying cables, torsion must be given both behind and before the
laying top. _Figs._ 947, 948, 949. represent the powerful patent
apparatus employed for this purpose. A, is a strong upright iron pillar,
supported upon the great horizontal beam N, N, and bearing at its upper
end the three-grooved laying top M. H, H, are two of the three great
bobbins or reels round which the three secondary strands or small
hawsers are wound. These are drawn up by the rotation of the three
feeding rollers I, I, I, thence proceed over the three guide pulleys K,
K, K, towards the laying top M, and finally pass through the tube O, to
be wound upon the cable-reel D. The frames of the three bobbins H, H, H,
do not revolve about the fast pillar A, as a common axis; but each
bobbin revolves round its own shaft Q, which is steadied by a bracing
collet at N, and a conical step at its bottom. The three bobbins are
placed at an angle of 120 degrees apart, and each receives a rotatory
motion upon its axis from the toothed spur wheel B, which is driven by
the common central spur wheel C. Thus each of the three secondary cords
has a proper degree of twist put into it in one direction, while the
cable is laid, by getting a suitable degree of twist in an opposite
direction, from the revolution of the frame or cage G, G, round two
pivots, the one under the pulley E, and the other over O. The reel D
has thus, like the bobbins H, H, two movements; that in common with its
frame, and that upon its axis, produced by the action of the endless
band round the pulley E, upon one of its ends, and the pulley E´ above
its centre of rotation. The pulley E is driven by the bevel mill-geering
P, P, P, as also the under spur wheel C. L, in _fig._ 949., is the place
of the ring L, _fig._ 947., which bears the three guide pulleys K, K, K.
_Fig._ 948. is an end view of the bobbin H, to show the worm or endless
screw J, of _fig._ 949., working into the two snail-toothed wheels, upon
the ends of the two feed-rollers I, I, which serve to turn them. The
upright shafts of J, J, receive their motion from pulleys and cords near
their bottom. Instead of these pulleys, and the others E, E´,
bevel-wheel geering has been substituted with advantage, not being
liable to slip, like the pulley-band mechanism. The axis of the great
reel is made twice the length of the bobbin D, in order to allow of the
latter moving from right to left, and back again alternately, in winding
on the cable with uniformity as it is laid. The traverse mechanism of
this part is, for the sake of perspicuity, suppressed in the figure.
Mr. William Norvell, of Newcastle, obtained a patent in May, 1833, for
an improvement adapted to the ordinary machines employed for twisting
hempen yarns into strands, affording, it is said, a simpler and more
eligible mode of accomplishing that object, and also of laying the
strands together, than has been hitherto effected by machinery. The
yarns spun from the fibres of hemp, are wound upon bobbins, and these
bobbins are mounted upon axles, and hung in the frame of the machine, as
shown in the elevation, _fig._ 950., from which bobbins the several ends
of yarn are passed upwards through slanting tubes; by the rotation of
which tubes, and of the carriages in which the bobbins are suspended,
the yarns become twisted into strands, and also the strands are laid so
as to form ropes.
[Illustration: 950]
His improvements consist, first, in the application of three or more
tubes, two of which are shown in _fig._ 950, placed in inclined
positions, so as to receive the strands immediately above the
press-block _a_, _a_, and nearly in a line with A, the point of closing
or laying the rope. B¹, and B³, are opposite side views; B², an edge
view; and B, a side section of the same. He does not claim any exclusive
right of patent for the tubes themselves, but only for their form and
angular position.
Secondly, in attaching two common flat sheaves, or pulleys, C, C, _fig._
950., to each of the said tubes, nearly round which each strand is
lapped or coiled, to prevent it from slipping, as shown in the section
B¹. The said sheaves or pulleys are connected by a crown or centre wheel
D, loose upon _b_, _b_, the main or upright axle; E, E, is a smaller
wheel upon each tube, working into the said crown or centre wheel, and
fixed upon the loose box I, on each of the tubes.
F, F, is a toothed or spur wheel, fixed also upon each of the loose
boxes I, and working into a smaller wheel G, upon the axis 2, of each
tube; H, is a bevel wheel fixed upon the same axis with G, and working
into another bevel wheel _J_, fixed upon the cross axle 3, of each tube;
K, is a spur wheel attached to the same axis with _J_, at the opposite
end, and working into L, another spur wheel of the same size upon each
of the tubes. By wheels thus arranged and connected with the sheaves or
pulleys, as above described, a perfectly equal strain or tension is put
upon each strand as drawn forward over the pulley C.
Thirdly, the invention consists in the introduction of change wheels M,
M, M, M, _fig._ 950., for putting the forehard or proper twist into each
strand before the rope is laid; this is effected by small spindles on
axles 4, 4, placed parallel with the line of each tube B.
Upon the lower end of each spindle the bevel wheels N, N, are attached,
and driven by other bevel wheels O, O, fixed immediately above each
press-block _a_, _a_. On the top end of each spindle or axle 4, 4, is
attached one of the change wheels, working into the other change wheel
fixed upon the bottom end of each of the tubes, whereby the forehard or
proper twist in the strands for all sizes of ropes, is at once attained,
by simply changing the sizes of those two last described wheels, which
can be very readily effected, from the manner in which they are attached
to the tubes B, B, and 4, 4.
From the angular position of the tubes towards the centre, the strands
are nearly in contact at their upper ends, where the rope is laid,
immediately below which the forehard or proper twist is given to the
strands.
Fourthly, in the application of a press-block P, of metal, in two parts,
placed directly above and close down to where the rope is laid at A, the
inside of which is polished, and the under end is bell-mouthed; to
prevent the rope from being chafed in entering it, a sufficient grip or
pressure is put upon the rope by one or two levers and weights 5, 5,
acting upon the press-block, so as to adjust any trifling irregularity
in the strand or in the laying; the inside of which being polished,
gives smoothness, and by the said levers and weights, a proper tension
to the rope, as it is drawn forward through the press-block. By the
application of this block, ropes may be made at once properly stretched,
rendering them decidedly preferable and extremely advantageous,
particularly for shipping, inclined planes, mines, &c.
The preceding description includes the whole of Mr. Norvell’s
improvements; the remaining parts of the machine being similar to those
now in use, may be briefly described as follows:--A wheel or pulley _c_,
is fixed independently of the machine, over which the rope passes to the
drawing motion represented at the side; _d_, _d_, is a grooved wheel,
round which the rope is passed, and pressed into the groove by means of
the lever and weight _e_, _e_, acting upon the binding sheaf _f_, to
prevent the rope from slipping. After the rope leaves the said sheave,
it is coiled away at pleasure. _g_, _g_, are two change wheels, for
varying the speed of the grooved wheel _d_, _d_, to answer the various
sizes of ropes; _h_, is a spiral wheel, driven by the screw _k_, fixed
upon the axle _l_; _m_, is a band-wheel, which is driven by a belt from
the shaft of the engine, or any other communicating power; _n_, _n_, is
a friction strap and striking clutch. The axle _q_, is driven by two
change wheels _p_, _p_; by changing the sizes of those wheels, the
different speeds of the drum R, R, for any sizes of ropes, are at once
effected.
[Illustration: 951]
The additional axle _s_, and wheels _t_, _t_, shown in _fig._ 951., are
applied occasionally for reversing the motion of the said drums, and
making what is usually termed left-hand ropes; _u_, _figs._ 950. and
951., show a bevelled pinion, driving the main crown wheel _v_, _v_,
which wheel carries and gives motion to the drums R, R; _w_, _w_, is a
fixed or sun wheel, which gives a reverse motion to the drums, as they
revolve round the same, by means of the intervening wheels _x_, _x_,
_x_, whereby the reverse or retrograding motion is produced, and which
gives to the strands the right twist. The various retrograding motions,
or right twists for all sizes and descriptions of ropes, may be obtained
by changing the diameters of the pinions _y_, _y_, _y_, on the under
ends of the drum spindles; the carriages of the intervening wheels _x_,
_x_, _x_, being made to slide round the ring _z_, _z_; W, W, is the
framework of the machine and drawing motion; T, T, T, are the bobbins
containing the yarns; their number is varied to correspond with the
different sizes of the machines.
The machine here described, in elevation and plan, is calculated to make
ropes from three to seven and one-half inches in circumference, and to
an indefinite length.
Messrs. Chapman of Newcastle, to whom the art of rope-making is deeply
indebted, having observed that rope yarn is considerably weakened by
passing through the tar-kettle, that tarred cordage loses its strength
progressively in cold climates, and so rapidly in hot climates as to be
scarcely fit for use in three years, discovered that the deterioration
was due to the reaction of the mucilage and acid of the tar. They
accordingly proposed the following means of amelioration. 1. Boiling it
with water, in order to remove these two soluble constituents. 2.
Concentrating the washed tar by heat, till it becomes pitchy, and then
restoring the plasticity which it thereby loses, by the addition of
tallow, or animal or expressed oils.
In 1807, the same able engineers obtained a patent for a method of
making a belt or flat band, of two, three, or more strands of shroud or
hawser-laid rope, placed side by side, so as to form a band of any
desired breadth, which may be used for hoisting the kibbles and corves
in mine-shafts, without any risk of its losing twist by rotation. The
ropes should be laid with the twist of the one strand directed to the
right hand, that of the other to the left, and that of the yarns the
opposite way to the strands, whereby perfect flatness is secured to the
band. This parallel assemblage of strands has been found also to be
stronger than when they are all twisted into one cylinder. The patentees
at the same time contrived a mechanism for piercing the strands
transversely, in order to brace them firmly together with twine. Flat
ropes are usually formed of hawsers with three strands, softly laid,
each containing 33 yarns, which with four ropes, compose a cordage four
and a half inches broad, and an inch and a quarter thick, being the
ordinary dimensions of the grooves in the whim-pulleys round which they
pass.
RELATIVE STRENGTH of CORDAGE, shroud laid.
+-------------+---------------++---------------++---------------+
|Size. |Warm Register. ||Cold Register. ||Common Staple. |
+-------------+---+---+---+---++---+---+---+---++---+---+---+---+
| | T | C | Q | L || T | C | Q | L || T | C | Q | L |
|3 inches bore| 3 |17 | |16 || 3 | 5 | 3 |16 || 2 | 9 | 1 |24 |
|3-1/2 -- | 5 | 5 | | || 4 | 9 | 2 |21 || 3 | 6 | 1 |27 |
|4 -- | 6 |17 | |16 || 5 |17 | | 4 || 4 | 5 | 3 | 7 |
|4-1/2 -- | 8 |13 | 2 | 8 || 7 | 5 | 3 | 1 || 5 | 1 | 2 | 6 |
|5 -- |10 |14 | 1 | 4 || 9 | 3 | | 4 || 6 | 9 | 2 | 8 |
|5-1/2 -- |12 |19 | 2 | 4 ||11 | 1 | 1 |25 || 7 |12 | |22 |
|6 -- |14 |15 | 2 |24 ||13 | 3 | 2 | 8 || 8 |17 | 1 |20 |
|6-1/2 -- |18 | 2 | |10 ||15 | 9 | 1 | 9 || 9 |16 | 3 |14 |
|7 -- |21 | | | ||17 |18 | 3 | 8 ||11 | 4 | 1 |21 |
|7-1/2 -- |24 | 2 | |16 ||20 |11 | 3 | 9 ||12 | 8 | 3 | 6 |
|8 -- |27 | 8 | 1 |26 ||23 | 8 | 2 | 8 ||13 | 2 | 3 |12 |
+-------------+---+---+---+---++---+---+---+---++---+---+---+---+
T = _Tons._
C = _Cwt._
Q = _Qrs._
L = _Lbs._
The above statement is the result of several hundred experiments.
ROSIN, or COLOPHANY (_Galipot_, Fr.; _Fichtenharz_, Germ.); is the rosin
left after distilling off the volatile oil from the different species of
turpentine. Yellow rosin contains some water, which black rosin does
not. See TURPENTINE.
ROSIN GAS. _Fig._ 952. exhibits the retort and its appendages, as
erected by Messrs. Taylor and Martineau, under the direction of the
patentee, Professor Daniel, F.R.S.
I have introduced this manufacturing project, not as a pattern to
imitate, but as an example to deter; as affording a very instructive
lesson of the danger of rushing headlong into most extensive
enterprises, without fully verifying, upon a moderate scale, the
probability of their ultimate success. The capital, labour, and time
annually wasted upon visionary schemes of this sort, got up by chamber
chemists, are incalculably great. No more essential service could be
rendered to the cause of productive industry, than to unmask the
thousand and one chimerical inventions which disgrace our lists of
patents during the last thirty years. These remarks have been suggested
by the circumstance, that 50,000_l._ were squandered upon the rosin-gas
concern; a fact communicated to me by an eminent capitalist, who was
induced by fallacious statements to embark largely in the speculation.
Had 100_l._ been employed beforehand, by a dispassionate practical man,
in making judicious trials, and in calculating the chances of eventual
profit and loss, it would have been demonstrated, as clearly as noonday,
that rosin could never compete with pitcoal in the production of
gas-light. Whatever ingenuity was expended in getting up the following
apparatus, may be regarded as an additional _ignis fatuus_ to mislead
the public, and divert their thoughts from the abyss that lay before
them. The main preliminary to be settled, in all new undertakings, is
the soundness of the principle. By neglecting this point, projectors
perpetually realize the expiatory fable of the Danaïds.
[Illustration: 952]
The retort _e_, _e_, _fig._ 952., is seen charged with coke, which is in
the first instance raised to a bright red heat, by means of the furnace
beneath. The common brown rosin of commerce, which is deposited in the
tank _a_, is to be mixed with the essential oil (condensed from the
rosin vapours in a preceding operation) in the proportion of one hundred
pounds of the former to ten gallons of the latter. The influence of the
flame and heated air beneath serves to preserve this in a fluid state,
and by a damper passing across the aperture in the chimney the
temperature of the fluid may be exactly regulated. A wire-gauze screen
at _f_, reaches to the bottom of the tank, and prevents the solid rosin,
or any impurity with which it may be mixed, from choking the stopcock.
The melted rosin having passed by the stopcock _b_, funnel _c_, and
syphon _d_, into the retort, falls on the coke, and in its passage
through the ignited mass, becomes decomposed. On arriving at the other
end of the retort, a large portion of the oil of turpentine, in the
form of condensable vapour, is separated by the refrigerator _g_; this
is supplied with water from a cistern above, and the non-condensable
vapour or gas passes up the tube _h_, and dips beneath the surface of
the fluid in the vessel _i_. This completes the condensation; and the
gas proceeds in a perfectly pure state, by the pipe _k_, to the
gasometer, or rather to the floating reservoir, for use.
The essential oil, when it leaves the refrigerator, is conveyed, by the
syphon _l_, to a cistern beneath. The necessity for employing a syphon
will be apparent, when it is borne in mind that the tube prevents the
escape of the gas, which would otherwise pass away from the box with the
essential oil. Another pipe and syphon _m_, _n_, serve to convey the
condensed essential oil from the top cistern.
ROTTEN-STONE. See TRIPOLI.
ROUGE. (_Fard_, Fr.) The only cosmetic which can be applied without
injury to brighten a lady’s complexion, is that prepared, by the
following process, from safflower (_Carthamus tinctorius_). The flowers,
after being washed with pure water till it comes off colourless, are
dried, pulverized, and digested with a weak solution of crystals of
soda, which assumes thereby a yellow colour. Into this liquor a quantity
of finely carded white cotton wool is plunged, and then so much lemon
juice or pure vinegar is added as to supersaturate the soda. The
colouring matter is disengaged, and falls down in an impalpable powder
upon the cotton filaments. The cotton, after being washed in cold water,
to remove some yellow colouring particles, is to be treated with a fresh
solution of carbonate of soda, which takes up the red colouring matter
in a state of purity. Before precipitating this pigment a second time by
the acid of lemons, some soft powdered talc should be laid in the bottom
of the vessel, for the purpose of absorbing the fine rouge, in
proportion as it is separated from the carbonate of soda, which now
holds it dissolved. The coloured mixture must be finally triturated with
a few drops of olive-oil, in order to make it smooth and marrowy. Upon
the fineness of the talc, and the proportion of the safflower
precipitate which it contains, depend the beauty and value of the
cosmetic. The rouge of the above second precipitation is received
sometimes upon bits of fine-twisted woollen stuff, called _crepons_,
which ladies rub upon their cheeks.
RUBY. See LAPIDARY.
RUM, is a variety of ardent spirits, distilled in the West Indies, from
the fermented skimmings of the sugar teaches, mixed with molasses, and
diluted with water to the proper degree. A sugar plantation in Jamaica
or Antigua, which makes 200 hogsheads of sugar, of about 16 cwt. each,
requires, for the manufacture of its rum two copper stills; one of 1000
gallons for the wash, and one of 600 gallons for the low wines, with
corresponding worm refrigeratories. It also requires two cisterns, one
of 3000 gallons for the lees or spent wash of former distillations,
called dunder (_Quasi redundar_, Span.), another for the skimmings of
the clarifiers and teaches of the sugar-house; along with twelve, or
more, fermenting cisterns or tuns.
Lees that have been used more than three or four times, are not
considered to be equally fit for exciting fermentation, when mixed with
the sweets, as fresher lees. The wort is made, in Jamaica, by adding to
1000 gallons of dunder, 120 gallons of molasses, 720 gallons of
skimmings (= 120 of molasses in sweetness), and 160 gallons of water; so
that there may be in the liquid nearly 12 per cent. of solid saccharum.
Another proportion, often used, is 100 gallons of molasses, 200 gallons
of lees, 300 gallons of skimmings, and 400 of water; the mixture
containing, therefore, 15 per cent. of sweets. These two formulæ
prescribe so much spent wash, according to my opinion, as would be apt
to communicate an unpleasant flavour to the spirits. Both the fermenting
and flavouring principles reside chiefly in the fresh cane juice, and in
the skimmings of the clarifier; because, after the syrup has been
boiled, they are in a great measure dissipated. I have made many
experiments upon fermentation and distillation from West India molasses,
and always found the spirits to be perfectly exempt from any rum
flavour.
The fermentation goes on most uniformly and kindly in very large masses,
and requires from 9 to 15 days to complete; the difference of time
depending upon the strength of the wort, the condition of its
fermentable stuff, and the state of the weather. The progress of the
attenuation of the wash should be examined from day to day with a
hydrometer, as I have described in the article DISTILLATION. When it has
reached nearly to its _maximum_, the wash should be as soon as possible
transferred by pumps into the still, and worked off by a properly
regulated heat; for if allowed to stand over, it will deteriorate by
acetification. Dr. Higgins’s plan, of suspending a basket full of
limestone in the wash-tuns, to counteract the acidity, has not, I
believe, been found to be of much use. It would be better to cover up
the wash from the contact of atmospheric air, and to add perhaps a very
little _sulphite_ of lime to it, both of which means would tend to
arrest the acetous fermentation. But one of the best precautions against
the wash becoming sour, is to preserve the utmost cleanliness among all
the vessels in the distillery. They should be scalded at the end of
every round with boiling water and quicklime.
About 115 gallons of proof rum are usually obtained from 1200 gallons of
wash. The proportion which the product of rum bears to that of sugar, in
very rich moist plantations, is rated, by Edwards, at 82 gallons of the
former to 16 cwt. of the latter; but the more usual ratio is 200 gallons
of rum to 3 hogsheads of sugar. But this proportion will necessarily
vary with the value of rum and molasses in the market, since whichever
fetches the most remunerating price, will be brought forward in the
greatest quantity. In one considerable estate in the island of Grenada,
92 gallons of rum were made for every hogshead (16 cwts.) of sugar. See
STILL.
Rum imported, in
1835. 1836. 1837.
Galls. 5,540,170; 4,993,942; 4,612,416.
Retained for Home Consumption.--
Duty 9_s._ per Imp. Gallon.
1835. 1836. 1837.
Galls. 3,416,966; 3,325,068; 3,184,599.
RUST, is the orange-yellow coat of peroxide which forms upon the surface
of iron exposed to moist air. Oil-paint, varnish, plumbago, or a film of
caoutchouc, may be employed, according to circumstances, to prevent the
rusting of iron utensils.
RYE, consists, according to the analysis of Einhof, of 24·2 of husk,
65·6 of flour, and 10·2 of water, in 100 parts. This chemist found in
100 parts of the flour, 61·07 of starch, 9·48 of gluten, 3·28 of
vegetable albumen, 3·28 of uncrystallizable sugar, 11·09 of gum, 6·38 of
vegetable fibre, and the loss was 5·62, including a vegetable acid not
yet investigated. Some phosphate of lime and magnesia are also present.
See GIN.