_Copaiva balsam_, balsam of copahu or capivi, is obtained from incisions
made in the trunk of the _Copaifera officinalis_, a tree which grows in
Brazil and Cayenne. It is pale yellow, middling liquid, clear
transparent, has a bitter, sharp, hot taste; a penetrating disagreeable
smell; a specific gravity of from 0·950 to 0·996. It dissolves in
absolute alcohol, partially in spirit of wine, forms with alkalis,
crystalline compounds. It consists of 45·59 ethereous oil, 52·75 of a
yellow brittle resin, and 1·66 of a brown viscid resin. The oil contains
no oxygen, has a composition like oil of turpentine, dissolves
caoutchouc (according to Durand), but becomes oxidised in the air, into
a peculiar species of resin. This balsam is used for making paper
transparent, for certain lacquers, and in medicine.
_Mecca balsam, or opobalsam_, is obtained both by incisions of, and by
boiling, the branches and leaves of the _Balsamodendron Gileadense_, a
shrub which grows in Arabia Felix, Lesser Asia and Egypt. When fresh it
is turbid, whitish, becomes, by degrees, transparent; yellow, thickish,
and eventually solid. It smells peculiar, but agreeable; tastes bitter
and spicy; does not dissolve completely in hot spirit of wine, and
contains 10 per cent. of ethereous oil, of the spec. grav. 0·876.
_Japan lac varnish_ flows from incisions in the trunk of the _Rhus
Vernix_ (_Melanorrhea usitata_) which is cultivated in Japan, and grows
wild in North America. The juice becomes black in the air; when
purified, dissolves in very little oil; and, mixed with colouring
matter, it constitutes the celebrated varnish of the Japanese.
For Benzoin and Turpentine, see these articles in their alphabetical
places.
BANDANNA. A style of calico printing, in which white or brightly
coloured spots are produced upon a red or dark ground. It seems to have
been practised from time immemorial in India, by binding up firmly with
thread, those points of the cloth which were to remain white or yellow,
while the rest of the surface was freely subjected to the dyeing
operations.
[Illustration: 96]
The European imitations have now far surpassed, in the beauty and
precision of the design, the oriental patterns; having called into
action the refined resources of mechanical and chemical science. The
general principles of producing bright figures upon dark grounds, are
explained in the article CALICO-PRINTING; but the peculiarities of the
Bandanna printing may be conveniently introduced here. In Brande’s
Journal for July 1823, I described the Bandanna gallery of Messrs.
Monteith at Glasgow, which, when in full action some years ago, might be
reckoned the most magnificent and profitable printing apartment in the
world. The white spots were produced by a solution of chlorine, made to
percolate down through the Turkey red cotton cloth, in certain points,
defined and circumscribed by the pressure of hollow lead types in
plates, in a hydraulic press. _Fig._ 96., is an elevation of one press;
A, the top or entablature; B B, the cheeks or pillars; C, the upper
block for fastening the upper lead perforated pattern to; D, the lower
block to which the fellow pattern is affixed, and which moves up and
down with the piston of the press; E, the piston or ram; F, the sole or
base; G, the water-trough, for the discharged or spotted calico to fall
into; H, the small cistern, for the aqueous chlorine or liquor-meter,
with glass tubes for indicating the height of liquor inside of the
cistern; _e e_, glass stopcocks, for admitting the liquor into that
cistern from the general reservoir; _f f_, stopcocks for admitting water
to wash out the chlorine; _g g_, the pattern lead-plates, with screws
for setting the patterns parallel to each other; _m m_, projecting
angular pieces at each corner, perforated with a half-inch hole to
receive the four guide-pins rising from the lower plate, which serve to
secure accuracy of adjustment between the two faces of the lead pattern
plates; _h h_, two rollers which seize and pull through the discharged
pieces, and deliver them into the water-trough. To the left of D there
is a stopcock for filling the trough with water; _l_, is the waste tube
for chlorine liquor and water of washing. The contrivance for blowing a
stream of air across the cloth, through the pattern tubes, is not
represented in the figure.
Sixteen engines, similar to the above, each possessing the power of
pressing with several hundred tons, are arranged in one line, in
subdivisions of four; the spaces between each subdivision serving as
passages to allow the workmen to go readily from the front to the back
of the presses. Each occupies twenty-five feet, so that the total length
of the apartment is 100 feet.
To each press is attached a pair of patterns in lead, (or plates as they
are called,) the manner of forming which will be described in the
sequel. One of these plates is fixed to the upper block of the press.
This block is so contrived, that it rests upon a kind of universal
joint, which enables this plate to apply more exactly to the under
fellow-plate. The latter sits on the moveable part of the press,
commonly called the sill. When this is forced up, the two patterns close
on each other very nicely, by means of the guide-pins at the corners,
which are fitted with the utmost care.
The power which impels this great hydrostatic range is placed in a
separate apartment, called the machinery room. This machinery consists
of two press cylinders of a peculiar construction, having solid rams
accurately fitted to them. To each of these cylinders, three little
force-pumps, worked by a steam-engine, are connected.
The piston of the large cylinder is eight inches in diameter, and is
loaded with a top-weight of five tons. This piston can be made to rise
about two feet through a leather-stuffing or collar. The other cylinder
has a piston of only one inch in diameter, which is also loaded with a
top-weight of five tons. It is capable, like the other, of being raised
two feet through its collar.
Supposing the pistons to be at their lowest point, four of the six small
force-pumps are put in action by the steam-engine, two of them to raise
the large piston, and two the little one. In a short time, so much water
is injected into the cylinders, that the loaded pistons have arrived at
their highest points. They are now ready for working the hydrostatic
discharge-presses, the water pressure being conveyed from the one
apartment to the other, under ground, through strong copper tubes, of
small calibre.
Two valves are attached to each press, one opening a communication
between the large driving-cylinder and the cylinder of the press, the
other between the small driving-cylinder and the press. The function of
the first is simply to lift the under-block of the press into contact
with the upper-block; that of the second, is to give the requisite
compression to the cloth. A third valve is attached to the press, for
the purpose of discharging the water from its cylinder, when the press
is to be relaxed, in order to remove or draw through the cloth.
From twelve to fourteen pieces of cloth, previously dyed Turkey-red, are
stretched over each other, as parallel as possible, by a particular
machine. These parallel layers are then rolled round a wooden cylinder,
called by the workmen, a drum. This cylinder is now placed in its proper
situation at the back of the press. A portion of the fourteen layers of
cloth, equal to the area of the plates, is next drawn through between
them, by hooks attached to the two corners of the webs. On opening the
valve connected with the eight-inch driving-cylinder, the water enters
the cylinder of the press, and instantly lifts its lower block, so as to
apply the under plate with its cloth, close to the upper one. This valve
is then shut, and the other is opened. The pressure of five tons in the
one inch prime-cylinder, is now brought to bear on the piston of the
press, which is eight inches in diameter. The effective force here will,
therefore, be 5 tons × 8² = 320 tons; the areas of cylinders being to
each other, as the squares of their respective diameters. The cloth is
thus condensed between the leaden pattern-plates, with a pressure of 320
tons, in a couple of seconds;--a splendid example of automatic art.
The next step, is to admit the blanching or discharging liquor, (aqueous
chlorine, obtained by adding sulphuric acid to solution of chloride of
lime,) to the cloth. This liquor is contained in a large cistern, in an
adjoining house, from which it is run at pleasure into small lead
cisterns H attached to the presses; which cisterns have graduated index
tubes, for regulating the quantity of liquor according to the pattern of
discharge. The stopcocks on the pipes and cisterns containing this
liquor, are all made of glass.
From the measure-cistern H, the liquor is allowed to flow into the
hollows in the upper lead-plate, whence it descends on the cloth, and
percolates through it, extracting in its passage the Turkey-red dye. The
liquor is finally conveyed into the waste pipe, from a groove in the
under block. As soon as the chlorine liquor has passed through, water is
admitted in a similar manner, to wash away the chlorine; otherwise, upon
relaxing the pressure, the outline of the figure discharged would become
ragged. The passage of the discharge liquor, as well as of the water
through the cloth, is occasionally aided by a pneumatic apparatus, or
blowing machine; consisting of a large gasometer, from which air
subjected to a moderate pressure, may be allowed to issue, and act in
the direction of the liquid, upon the folds of the cloth. By an
occasional twist of the air stopcock, the workman also can ensure the
equal distribution of the discharging liquor, over the whole excavations
in the upper plate. When the demand for goods is very brisk, the air
apparatus is much employed, as it enables the workman to double his
product.
The time requisite for completing the discharging process in the first
press is sufficient to enable the other three workmen to put the
remaining fifteen presses in play. The discharger proceeds now from
press to press, admits the liquor, the air, and the water; and is
followed at a proper interval by the assistants, who relax the press,
move forwards another square of the cloth, and then restore the
pressure. Whenever the sixteenth press has been liquored, &c., it is
time to open the first press. In this routine, about ten minutes are
employed; that is 224 handkerchiefs (16 × 14) are discharged every ten
minutes. The whole cloth is drawn successively forward, to be
successively treated in the above method.
When the cloth escapes from the press, it is passed between the two
rollers in front; from which it falls into a trough of water placed
below. It is finally carried off to the washing and bleaching
department, where the lustre of both the white and the red is
considerably brightened.
By the above arrangement of presses, 1600 pieces, consisting of 12 yards
each = 19,200 yards, are converted into Bandannas in the space of ten
hours, by the labour of four workmen.
The patterns, or plates, which are put into the presses to determine the
white figures on the cloth, are made of lead in the following way. A
trellis frame of cast-iron, one inch thick, with turned-up edges,
forming a trough rather larger than the intended lead pattern, is used
as the solid ground-work. Into this trough, a lead plate about one half
inch thick, is firmly fixed by screw nails passing up from below. To the
edges of this lead plate, the borders of the piece of sheet-lead are
soldered, which covers the whole outer surface of the iron frame. Thus a
strong trough is formed, one inch deep. The upright border gives at once
great strength to the plate, and serves to confine the liquor. A thin
sheet of lead is now laid on the thick lead-plate, in the manner of a
veneer on toilette-tables, and is soldered to it round the edges. Both
sheets must be made very smooth beforehand, by hammering them on a
smooth stone table, and then finishing with a plane: the surface of the
thin sheet (now attached), is to be covered with drawing paper, pasted
on, and upon this the pattern is drawn. It is now ready for the cutter.
The first thing which he does, is to fix down with brass pins all the
parts of the pattern which are to be left solid. He now proceeds with
the little tools generally used by block-cutters, which are fitted to
the different curvatures of the pattern, and he cuts perpendicularly
quite through the thin sheet. The pieces thus detached are easily lifted
out; and thus the channels are formed which design the white figures on
the red cloth. At the bottom of the channels, a sufficient number of
small perforations are made through the thicker sheet of lead, so that
the discharging liquor may have free ingress and egress. Thus, one plate
is finished; from which, an impression is to be taken by means of
printers’ ink, on the paper pasted upon another plate. The impression is
taken in the hydrostatic press. Each pair of plates constitutes a set,
which may be put into the presses, and removed at pleasure.
BARBERRY. The root of this plant contains a yellow colouring matter,
which is soluble in water and alcohol, and is rendered brown by alkalis.
The solution is employed in the manufacture of Morocco leather.
BARILLA. A crude soda, procured by the incineration of the _salsola
soda_, a plant cultivated for this purpose in Spain, Sicily, Sardinia,
&c. Good barilla usually contains, according to my analysis, 20 per
cent. of real alkali, associated with muriates and sulphates, chiefly of
soda, some lime, and alumina, with very little sulphur. Caustic lyes
made from it, are used in the finishing process of the hard soap
manufacture. 125,068 cwts. were imported in 1835, of which only 5,807
were exported. The duty is 2_s._ per cwt. Of the above quantity, 64,174
came from Spain and the Balearic islands, 39,943 from the Canaries, and
20,432 from Italy and the Italian islands.
BARIUM, the metallic basis of Baryta.
BARK OF OAK, for tanning. Unfortunately, the Tables of Revenue published
by the Board of Trade, mix up this bark and the dyeing barks together,
and give the sum of the whole for 1835, at 826,566 cwts., of which only
2,264 were re-exported. The duty is 1_d._ per cwt. from British
possessions, and 8_d._ from other parts.
BARLEY (_Orge_, Fr. _Gerste_, Germ.) English barley is that with
two-rowed ears, or the _hordeum vulgare distichon_ of the botanists; the
Scotch beer or bigg, is the _hordeum vulgare hexastichon_. The latter
has two rows of ears, but 3 corns come from the same point, so that it
seems to be six-eared. The grains of bigg are smaller than those of
barley, and the husks thinner. The specific gravity of English barley
varies from 1·25 to 1·33; of bigg from 1·227 to 1·265; the weight of the
husk of barley is 1/6, that of bigg 2/9. 1000 parts of barley flour
contain, according to Einhof, 720 of starch, 56 sugar, 50 mucilage, 36·6
gluten, 12·3 vegetable albumen, 100 water, 2·5 phosphate of lime, 68
fibrous or ligneous matter. Sp. gravity of barley, is 1·235 by my
trials.
BARM. The yeasty top of fermenting beer. See BEER, DISTILLATION,
FERMENTATION.
BARYTA or BARYTES, one of the simple earths. It may be obtained most
easily by dissolving the native carbonate of barytes (Witherite) in
nitric acid, evaporating the neutral nitrate till crystals be formed,
draining and then calcining these in a covered platina crucible, at a
bright red heat. A less pure baryta may be obtained by igniting strongly
a mixture of the carbonate and charcoal, both in fine powder and
moistened. It is a grayish white earthy looking substance, fusible only
at the jet of the oxy-hydrogen blowpipe, has a sharp caustic taste,
corrodes the tongue and all animal matter, is poisonous even in small
quantities, has a very powerful alkaline reaction; a specific gravity of
4·0; becomes hot, and slakes violently when sprinkled with water,
falling into a fine white powder, called the hydrate of baryta, which
contains 10-1/2 per cent. of water, and dissolves in 10 parts of boiling
water. This solution lets fall abundant columnar crystals of hydrate of
baryta as it cools; but it still retains one twentieth its weight of
baryta, and is called baryta water. The above crystals contain 61 per
cent. of water, of which, by drying, they lose 50 parts. This hydrate
may be fused at a red heat without losing any more water. Of all the
bases, baryta has the strongest affinity for sulphuric acid, and is
hence employed either in the state of the above water, or in that of one
of its neutral salts, as the nitrate or muriate, to detect the presence,
and determine the quantity of that acid present in any soluble compound.
Its prime equivalent, according to Berzelius, is 956,880, oxygen being
100; or 76,676, hydrogen being 1,000. Native sulphate of baryta, or
heavy spar, is fraudulently used to adulterate white lead by the English
dealers to a shameful extent.
BASSORINE. A constituent part of a species of gum which comes from
Bassora, as also of gum tragacanth, and of some gum resins. It is
semi-transparent, difficult to pulverise, swells considerably in cold or
boiling water, and forms a thick mucilage without dissolving. Treated
with ten times its weight of nitric acid, it affords nearly 23 per cent.
of its weight of mucic acid, being much more than is obtainable from gum
arabic or cherry-tree gum. Bassorine is very soluble in water slightly
acidulated with nitric or muriatic acid. This principle is procured by
soaking gum Bassora in a great quantity of cold water, and in removing,
by a filter, all the soluble parts.
BATHS. (_Bains_, Fr. _Baden_, Germ.) Warm baths have lately come into
very general use, and they are justly considered as indispensably
necessary in all modern houses of any magnitude, as also in club-houses,
hotels, and hospitals. But the mode of constructing these baths, and of
obtaining the necessary supplies of hot and cold water, does not appear
to have undergone an improvement equal to the extension of their
employment.
The several points in regard to warm baths, are,
1. The materials of which they are constructed.
2. Their situation.
3. The supply of cold water.
4. The supply of hot water.
5. Minor comforts and conveniences.
1. As to the materials of which they are constructed.--Of these the best
are slabs of polished marble, properly bedded with good water-tight
cement, in a seasoned wooden case, and neatly and carefully united at
their respective edges. These, when originally well constructed, form a
durable, pleasant, and agreeable-looking bath; but the expense is often
objectionable, and, in upper chambers, the weight may prove
inconvenient. If of white or veined marble, they are also apt to get
yellow or discoloured by frequent use, and cannot easily be cleansed; so
that large Dutch tiles, as they are called, or square pieces of white
earthenware, are sometimes substituted; which, however, are difficultly
kept water-tight; so that, upon the whole, marble is preferable.
Where there are reasons for excluding marble, copper or tinned iron
plate is the usual material resorted to. The former is most expensive in
the outfit, but far more durable than the latter, which is, moreover,
liable to leakage at the joints, unless most carefully made. Either the
one or the other should be well covered outside and inside, with several
coats of paint, which may then be marbled, or otherwise ornamented.
Wooden tubs, square or oblong, and oval, are sometimes used for warm
baths; and are cheap and convenient, but neither elegant nor cleanly.
The wood always contracts a mouldy smell; and the difficulty and
nuisance of keeping them water-tight, and preventing shrinkage, are such
as to exclude them from all except extemporaneous application.
2. As to the situation of the bath, or the part of the house in which it
is to be placed.--In hotels, and club-houses, this is a question easily
determined: several baths are usually here required, and each should
have annexed to it, a properly warmed dressing-room. Whether they are up
stairs or down stairs, is a question of convenience, but the basement
story, in which they are sometimes placed, should always be avoided;
there is a coldness and dampness belonging to it, in almost all
weathers, which is neither agreeable nor salubrious.
In hospitals, there should be at least two or three baths on each side
of the house, (the men’s and women’s), and the supply of hot water
should be ready at a moment’s notice. The rooms in which the baths are
placed should be light and comparatively large and airy; and such
conveniences for getting into and out of the bath should be adopted, as
the sick are well known to require. The dimensions of these baths should
also be larger than usual.
In private houses, the fittest places for warm baths are dressing-rooms
annexed to the principal bed-rooms; or, where such convenience cannot be
obtained, a separate bath-room, connected with the dressing-room, and
always upon the bed-room floor. All newly-built houses should be
properly arranged for this purpose, and due attention should be paid to
the warming of the bath-room, which ought also to be properly
ventilated. A temperature of 70° may be easily kept up in it, and
sufficient ventilation is absolutely requisite, to prevent the
deposition of moisture upon the walls and furniture.
The objection which formerly prevailed, in respect to the difficulty of
obtaining adequate supplies of water, in the upper rooms, has been
entirely obviated, by having cisterns at or near the top of the house;
and we would just hint that these should be so contrived, as to be
placed out of the reach of frost; a provision of the utmost importance
in every point of view, and very easily effected in a newly-built house,
though it unfortunately happens, that architects usually regard these
matters as trifles, and treat them with neglect, as indeed they do the
warming and ventilation of buildings generally.
3. The supply of water of proper quality and quantity, is a very
important point, as connected with the present subject. The water should
be soft, clean, and pure; and as free as possible from all substances
mechanically suspended in it. In many cases, it answers to dig a well
for the exclusive supply of a large house with water. In most parts of
London this may effectually be accomplished, at a comparatively moderate
expense; and, if the well be deep enough, the water will be abundant,
soft, and pellucid. The labour of forcing it by a pump to the top of the
house, is the only drawback; this, however, is very easily done by a
horse-engine, or there are people enough about town, glad to undertake
it at a shilling a day. I am led to these remarks by observing the
filthy state of the water usually supplied, at very extravagant rates,
by the water companies. It often partakes more of the appearance of
pea-soup than of the pure element; fills our cisterns and pipes with mud
and dirt, and, even when cleared by subsidence, is extremely
unpalatable. It deposits its nastiness in the pipes connected with warm
baths, and throws down a slippery deposit upon the bottom of the vessel
itself to such an extent, as often to preclude its being used, at least
as a luxury, which a clear and clean bath really is. This inconvenience
may, in some measure, be avoided, by suffering the water to throw down
its extraneous matters upon the bottom of the cistern, and drawing our
supplies from pipes a little above it; there will, however, always be
more or less deposit in the pipes themselves; and every time the water
runs into the cistern, the grouts are stirred up, and diffused through
its mass: this, from some cause or other, has lately become an
intolerable nuisance; and he who reflects upon the miscellaneous
contents of Thames water, will not have his appetite sharpened by a
draught of the Grand Junction beverage, nor feel reanimated and
refreshed by bathing in a compound so heterogeneous and unsavoury.
4. and 5. In public bathing establishments, where numerous and constant
baths are required, the simplest and most effective means of obtaining
hot water for their supply consists in drawing it directly into the
baths from a large boiler, placed somewhere above their level. This
boiler should be supplied with proper feeding-pipes and gauges; and,
above all things, its dimensions should be ample; it should be of
wrought iron or copper, except where sea water is used, in which case
the latter metal is sometimes objectionable. The hot water should enter
the bath by a pipe at least an inch and a half in diameter; and the cold
water by one of the same dimension, or somewhat larger, so that the bath
may not be long in filling. The relative proportions of the hot and cold
water are, of course, to be adjusted by a thermometer, and every bath
should have a two-inch waste-pipe, opening about two inches from the top
of the bath, and suffering the excess of water freely to run off; so
that when a person is immersed in the bath, or when the supplies of
water are accidentally left open, there may be no danger of an overflow.
Where there is a laundry in the upper story of the house, or other
convenient place for erecting a copper and its appurtenances, a plan
similar to the above may often be conveniently adopted in private
houses, for the supply of a bath upon the principal bed-room floor. An
attempt is sometimes made to place boilers behind the fires of
dressing-rooms, or otherwise to erect them in the room itself, for the
purpose of supplying warm water; but this plan is always objectionable,
from the complexity of the means by which the supply of water is
furnished to the boiler, and often dangerous from the flues becoming
choaked with soot, and taking fire. Steam is also apt, in such cases, to
escape in quantities into the room; so that it becomes necessary to
search for other methods of heating the bath; one or two of the least
objectionable of which I shall describe.
1. A contrivance of some ingenuity consists in suffering the water for
the supply of the bath to flow from a cistern above it, through a leaden
pipe of about one inch diameter, which is conducted into the kitchen or
other convenient place where a large boiler for the supply of hot water
is required. The bath-pipe is immersed in this boiler, in which it makes
many convolutions, and, again emerging, ascends to the bath. The
operation is simply this:--the cold water passing through the
convolutions of that part of the pipe which is immersed in the boiling
water, receives there sufficient heat for the purpose required, and is
delivered in that state by the ascending pipe into the bath, which is
also supplied with cold water and waste-pipes as usual. The pipe may be
of lead, as far as the descending and ascending parts are concerned, but
the portion forming the worm, or convolutions immersed in the boiler
should be copper, in order that the water within it may receive heat
without impediment.
This plan is economical only where a large boiler is constantly kept at
work in the lower part of the house; otherwise, the trouble and expense
of heating such a boiler, for the mere purpose of the bath, render it
unavailable. The worm-pipe is also apt to become furred, upon the
outside, by the deposition of the earthy impurities of the water in
which it is immersed; it then becomes a bad conductor of heat, is
cleansed with difficulty, and the plan is rendered ineffective. This
system, however, has been adopted, in some particular cases, with
satisfaction.
2. A much more simple, economical, and independent mode of heating a
warm bath, by a fire placed at a distance from it, is the following,
which is found to answer perfectly in private houses, as well as upon a
more extended scale in large establishments. It is certainly open to
some objections, but these are overbalanced by its advantages. A
waggon-shaped boiler, holding about six gallons of water, is properly
placed over a small furnace, in any convenient and safe part of the
house, as the kitchen, scullery, servants’ hall, or wash-house. The bath
itself, of the usual dimensions and construction, is placed where it is
wanted, with a due supply of cold water from above. Two pipes issue from
within an inch of the bottom of the bath at its opposite extremities;
one at the head of the bath, about one inch, and the other at the foot,
an inch and one eighth in diameter. These tubes descend to the boiler,
the smaller one entering it at the bottom, and the larger one issuing
from its top.
Under these circumstances, supposing the pipes and boiler every where
perfectly tight, when the bath is filled, the water will descend into
and expel the air from the boiler, and completely fill it. Now, upon
making a gentle fire under the boiler, an ascending current of warm
water will necessarily pass upwards through the larger pipe which issues
from its top, and cold water will descend by the pipe which enters at
the bottom; and thus, by the establishment of currents, the whole mass
of water in the bath will become heated to the desired point; or, if
above it, the temperature may easily be lowered by the admixture of cold
water.
The advantages of this form of bath are numerous. The shorter the pipes
of communication the better, but they may extend forty or fifty feet
without any inconvenience beyond that of expense; so that there is no
obstacle to the bath being near the bed-room while the boiler is on the
basement story. There is but little time required for heating the bath;
the water in which may, if requisite, be raised to about 100° in about
half an hour from the time of lighting the fire. The consumption of fuel
is also trifling.
The following are the chief disadvantages attendant upon this plan, and
the means of obviating them:--
It is necessary, when the water has acquired its proper temperature, to
withdraw the fire from the boiler, or not to use the bath immediately,
as it may go on acquiring some heat from the boiler, so that we may
become inconveniently hot in the bath. When, therefore, this bath is
used, we may proceed as follows:--heat the water in it an hour before it
is wanted, to about 100°, and then extinguish the fire. The water will
retain its temperature, or nearly so, for three or four hours,
especially if the bath be shut up with a cover; so that when about to
use it, cold water may be admitted till the temperature is lowered to
the required point, and thus all the above inconveniences are avoided.
Another disadvantage of this bath arises from too fierce a fire being
made under the boiler, so as to occasion the water to boil within it, a
circumstance which ought always to be carefully avoided. In that case,
the steam rising in the upper part of the boiler, and into the top pipe,
condenses there, and occasions violent concussions, the noise of which
often alarms the whole house, and leads to apprehensions of explosion,
which, however, is very unlikely to occur; but the concussions thus
produced injure the pipes, and may render them leaky: so that in regard
to these, and all other baths, &c., we may remark, that the pipes should
pass up and down in such parts of the house as will not be injured if
some leakage takes place; and under the bath itself should be a
sufficiently large leaden tray with a waste-pipe, to receive and carry
off any accidental drippings, which might injure the ceilings of the
rooms below. In all newly-built houses, two or three flues should be
left in proper places for the passage of ascending and descending
water-pipes; and these flues should in some way receive at their lower
part a little warm air in winter, to prevent the pipes freezing: the
same attention should also be paid to the situation of the cisterns of
water in houses, which should be kept within the house, and always
supplied with a very ample waste-pipe, to prevent the danger of
overflow. Cisterns thus properly placed, and carefully constructed,
should be supplied from the water-mains by pipes kept under ground, till
they enter the house, and not carried across the area, or immediately
under the pavement, where they are liable to freeze.
3. Baths are sometimes heated by steam, which has several advantages: it
may either be condensed directly into the water of the bath, or, if the
bath be of copper or tinned iron, it may be conducted into a casing upon
its outside, usually called a jacket; in the latter case there must be a
proper vent for the condensed water, and for the escape of air and waste
steam. Steam is also sometimes passed through a serpentine pipe, placed
at the bottom of the bath. But none of these methods are to be
recommended for adoption in private houses, and are only advisable in
hospitals, or establishments where steam boilers are worked for other
purposes than the mere heating of baths.
Many copper and tin baths have been lately constructed in London, with a
little furnace attached to one end, and surrounded with a case or
jacket, into which the water flows and circulates backwards and forwards
till the whole mass in the bath gets heated to the due degree. One of
the best of these is that constructed by Mr. Benham, of Wigmore Street.
The bath must be placed near the fire-grate, and the smoke-pipe of the
attached furnace be conducted up the chimney a certain way to secure a
sufficient draught to maintain combustion. The above bath, well managed,
heats the water from 50° to 98° in about 20 or 25 minutes, as I have
experimentally proved. When the proper temperature is attained, the fire
must of course be extinguished.
BDELLIUM. A gum resin, produced by an unknown plant which grows in
Persia and Arabia. It comes to us in yellowish or reddish pieces, smells
faintly, like myrrh, and consists of 59 resin, 9·2 gum, 30·6 bassorine,
and 1·2 ethereous oil.
BEER. (_Bière_, Fr. _Bier_, Germ.) The fermented infusion of malted
barley, flavoured with hops, constitutes the best species of beer; but
there are many beverages of inferior quality to which this name is
given, such as spruce beer, ginger beer, molasses beer, &c.; all of
which consist of a saccharine liquor, partially advanced into the vinous
fermentation, and flavoured with peculiar substances.
The ancients were acquainted with beer, and the Romans gave it the
appropriate name of _Cerevisia_ (quasi _Ceresia_), as being the product
of corn, the gift of Ceres. The most celebrated liquor of this kind in
the old time, was the _Pelusian_ potation, so called from the town where
it was prepared at the mouth of the Nile. Aristotle speaks of the
intoxication caused by beer; and Theophrastus very justly denominated it
the _wine of barley_. We may, indeed, infer from the notices found in
historians, that drinks analogous to our beer were in use among the
ancient Gauls, Germans, and in fact almost every people of our temperate
zone; and they are still the universal beverage in every land where the
vine is not an object of rustic husbandry.
The manufacture of beer, or the art of brewing, may be conveniently
considered under five heads:--
1. An examination of the natural productions which enter into its
composition; or of barley and hops.
2. The changes which barley must undergo to fit it for making beer; or
the processes of malting and mashing.