10. Sulphur, or squills, in impalpable powder, blown into the cracks or
joints, or scattered in a fine cloud, by means of a hollow ball or balloon
of vulcanised india rubber filled with it and furnished with a small
wooden jet or mouth-piece, or in any other convenient manner. Very cleanly
and effective. Dumont's 'Patent Vermin Killer,' as well as the whole host
of imitations of it, is of this kind.
_Obs._ Out of the above list there is ample room for selection. The common
practice is to take the bedstead or other piece of furniture to pieces
before applying them.
These pests exist only in dirty houses. A careful housewife or servant
will soon completely destroy them. The surest method of destruction is to
catch them individually when they attack the person in bed. When their
bite is felt, instantly rise and light a candle and capture them. This may
be troublesome, but if there be not a great number a few nights will
finish them. When there is a large number, and they have gained a lodgment
in the timbers, take the bed in pieces, and fill in all the apertures and
joints with a mixture of soft soap and Scotch snuff. A piece of
wicker-work, called a BUG-TRAP, placed at the head of the bed, forms a
receptacle for them, and then they may be daily caught till no more are
left. Oil-painting a wall is a sure means of excluding and destroying
them. It has been asserted that these insects are so fond of narrow-leaved
dittany or pepperwort (_lepidium ruderale_), that if a bunch of it be
suspended near their haunts they will settle in it, and may be thus easily
captured. It is said to be commonly used as a bug-trap in some of our
rural districts. Water, poured boiling from the spout of a kettle into the
cracks and joints, is a cleanly and certain remedy, which we have often
seen employed; so also is a jet of steam; they are both destructive to all
insects, and will be found particularly so to beetles.
The proper time for attacking these pests is early in March, or shortly
before they are revived from their dormant state by the warm weather. See
INSECTS.
=Bug, Harvest.= See ACARI.
=BU'GLE= (bu'gl). An elongated cylindrical glass bead. See BEAD.
=BUILDING STONES.= Amongst the calcareous and magnesian stones used for
building many of the fine-grained and porous varieties are liable to split
into flakes after a few years' exposure to the atmosphere, owing to the
absorption by the stone of water, which, becoming frozen during severe
weather, fractures the stone by its expansion. Brard invented a simple
means of ascertaining whether a building stone is liable to this defect,
which consists in taking a smoothly-cut block of the stone, one or two
inches square, and placing it in a cold saturated solution of sodic
sulphate. The temperature of the solution is gradually raised to the
boiling point; it is allowed to boil for half an hour, and then the stone
is left to cool in the liquid. When cold it is suspended over a dish, and
once a day for a week or a fortnight plunged for a few moments into a cold
saturated solution of sodic sulphate, and it is then again freely
suspended in the air. The sulphate crystallises in the pores of the stone
and splits off fragments of it. A similar experiment is made upon an
equal-sized mass of stone which is known to be free from this defect. By
the comparative weight of these fragments in the two cases the tendency of
the stone to the defect in question may be estimated.
A stone that is placed in a building in a position similar to that in
which it is found in the quarry, that is, with its seams lying
horizontally, is found to resist the weather much more successfully than
one that has not been so placed.
=BUN.= A well-known kind of light, sweet cake.
_Prep._ 1. BATH-BUNS:--As 6, but adding a little candied lemon and orange
peel, and putting a little grated peel and a few caraway comfits on the
top of each.
2. CROSS-BUNS:--Flour, 2-1/2 lbs.; sifted sugar 1/2 lb.; coriander seeds,
cassia, and mace, of each (powdered) a sufficiency; make a paste with
butter, 1/2 lb.; (dissolved in) hot milk, 1/2 pint; work with three
table-spoonfuls of yeast; set it before the fire for an hour to rise, then
make it into buns, and set them before the fire on a tin for half an hour;
lastly, brush them over with warm milk, and bake them to a nice brown in a
moderate oven.
3. MADEIRA-BUNS:--Butter, 8 oz.; 2 eggs; flour, 1 lb.; powdered sugar, 6
oz.; half a nutmeg (grated); powdered ginger and caraway seeds, of each
1/2 teaspoonful; work well together, then add as much milk as required,
and ferment; lastly, bake on tins in a quick oven.
4. PLAIN BUNS:--Flour, 2 lbs.; butter, 1/4 lb.; sugar, 6 oz.; a little
salt, caraway and ginger; make a paste with yeast, 4 spoonfuls, and warm
milk, q. s.; as before.
5. PENNY-BUNS:--To the last add of currants, well washed, 1/2 lb.; and
water, stained by steeping a little saffron in it, q. s., to give a light
yellow tinge to them.
6. RICH BUNS:--Fine flour, 3 lbs; sugar, 1 lb.; butter, 2 lbs. (melted and
beat with) rose water, 4 oz.; currants, 1 lb.; yeast, 1/4 pint; as before.
_Obs._ The great secret in producing good buns is the use of sweet yeast
and the best currants only, and thoroughly washing these last in a sieve
or colander, to remove grit, before adding them to the dough.
=BUNION= (-y[)u]n). A species of corn or swelling on the ball of the great
toe, resulting from pressure, and irritation by friction. The treatment
recommended for corns applies also to bunions; but in consequence of the
greater extension of the disease, the cure is more tedious. A bunion may
often be effectually stopped and removed by poulticing it, and, at the
proper time, carefully opening it with a lancet. See CORNS.
=BURETTE.= A graduated glass vessel employed in volumetric analysis for
measuring liquids.
1. The first burette was invented by Gay-Lussac, a drawing of whose
instrument is given below.
It rarely, if ever, has a capacity greater than 50 cubic centimetres, and
consists of a narrow tube fused on to a wider one. The larger tube is
about 33 centimetres long, the graduated portion occupying about 25
centimetres, and its internal diameter measures 15 millimetres; the narrow
tube has a diameter of 4 millimetres, which in the upper bent end
decreases to 2 millimetres. When used the instrument should be held in the
left hand, the bottom part being allowed to lean a little against the
chest. The operation is aided by giving the instrument from time to time a
slight turn in the direction of its longitudinal axis, thereby placing the
curve of the stout alternately in a more vertical, alternately in a more
horizontal position. The volume must not be read off before the surface of
the liquid has attained a constant height.
2. Geissler's burette. This instrument differs from Gay-Lussac's in having
the narrow tube inside, instead of outside the wider one. It is found very
convenient in use, and is less liable to fracture than Gay-Lussac's.
3. Mohr's burette, which can be more easily and readily managed than
either of the two preceding ones, is described and figured under
ALKALIMETRY.
[Illustration: Gay-Lussac's Burette and Geissler's Burette.]
In volumetric analysis the method of taking the readings of the burette is
an operation of great importance, requiring considerable method and
practice.
The first proceeding is to bring the eye to a level with the fluid, and to
adopt a fixed and unalterable standard of what is to be considered the
surface.
If you hold a burette partly filled with water between the eye and a
strongly illumined wall, the surface of the fluid presents the appearance
shown in fig. _a._ If you hold close behind the tube a sheet of white
paper with a strong light falling on it, the surface of the fluid will
present an appearance similar to that shown in fig. _b._
In both cases you have read off at the lower border of the dark zone, this
being the most distinctly marked line. Its distinctness may be heightened
by adopting Mohr's contrivance which consists in pasting on a sheet of
very white cardboard a broad strip of black paper, and when reading off
holding this close behind the burette in a position to place the border
line between white and black from 2 to 3 millimetres below the lower
border of the dark zone as shown in figure _c._
[Illustration: _a._ and _b._]
[Illustration: _c._]
Great care must be taken to hold the paper invariably in the same
position, since if it be held lower down, the lower border of the black
zone will move higher up.
To test the correctness of the graduation of a burette proceed as
follows:--Fill the instrument up to the highest division with water at
60·8° F., then let the cubic centimetres of the liquid flow out into an
accurately weighed flask, and determine the weight of these ten cubic
centimetres in the usual way; then let another quantity of ten cubic
centimetres flow out, and weigh again, and repeat the operation till the
contents of the burette are exhausted. If the instrument is correctly
graduated, every ten cubic centimetres of water at 60·8° F. must weigh
9·990 grammes.
=BURG'LARIES.= The common precautions of locks and bolts, alarum-bells and
fire-arms, are frequently found useless in preserving houses from
burglars; but a light in the upper part of the house, or a small dog on
the ground-floor, with the means of running into a place of safety from
its enemies, has been seldom known to fail. A combination of the two would
undoubtedly be doubly effective. The bark of the dog and the fear of
detection by the approach of the light would deter the majority of rogues
of common pluck and feeling. A dog out of doors, and consequently
accessible, however large and fierce, is easily pacified or silenced by
men of the class referred to.
=BURLS, REMOVAL OF, from Cloth and Wool.= Introduce the wool or the
woollen goods into 100 litres of sulphuric acid at 6° B., in which 500
grams of alum and 250 grams of salt have been dissolved. Work in this bath
for one or two hours, drain in the centrifugal, and hang up at 100° to
120°. Wash for an hour and a half in clear water, treat for two hours with
fuller's earth, soda and lime, and wash again for two hours. Sulphuric
acid is adapted only for whites and indigo blues. For coloured goods
solutions of chloride of tin, and chloride of manganese at 6° B., are
recommended.
=BURNS[234] and Scalds.[235]= _Treatm._ When the injury is superficial and
slight, a little creosote may be applied to the part. If a scald, the
vesicle should be first pierced with a needle, or what is better, snipped
with a pair of scissors, and the water which it contains should be then
gently squeezed out. When creosote is not procurable, a liniment formed of
equal parts of soft soap, basilicon ointment, oil of turpentine, and
water, may be used instead. When the part feels very hot and painful, a
poultice may be applied, on the surface of which a few drops of creosote,
or of the liniment, should be spread with a knife. This treatment will
generally succeed in allaying the pain. It may be followed by a dressing
of zinc ointment, or any other like simple emollient or unctuous
preparation. Creosote, contrary to what is commonly asserted, produces
scarcely any smarting or pain; whilst it rapidly removes the burning
sensation, and the charred surface soon assumes a dry scabby appearance,
which, by dressing with simple ointment, soon comes off and leaves the
part beneath in a sound and healthy state. If a poultice be applied it is
best to keep it on until the next day. Plunging the part into very cold
water immediately after the receipt of an injury of this kind will
frequently prevent any further remedy being required. Flexible collodion
painted over a burn forms a good protective envelope. In all cases cooling
laxatives should be administered; and the diet should be rather low until
the inflammatory symptoms subside.
[Footnote 234: BURN, s. sing.; AMBUS'TIO, L. BRÛLURE, Fr.; BRAND,
BRANDMAHL, Ger.]
[Footnote 235: See SCALDS (under _S_).]
_Treatment for Animals._ Carbolic dressing, exclusion of air, cotton wool,
linseed oil and lime water.
=BURNING-GLASS.= See LENS.
=BUTEA FRONDOSA=, _Roxb._ (Ind. Ph.) _Syn._ BENGAL KINO TREE. _Habitat._
Common all over India.--_Officinal part._ The inspissated juice obtained
from the stem by incision (_Buteæ Gummi_, _Kino Bengalensis_, _Bengal
kino_). It occurs in the form of irregular shining fragments, seldom as
large as a pea; more or less mixed with adherent pieces of greyish bark;
of an intense ruby colour and astringent taste; soluble, but not freely
so, in water and in alcohol. Its astringency is due to the presence of
tannic and gallic acids.--_Prop. & Uses._ Similar to those of kino, for
which it has been found an efficient substitute.--_Prep._ Same as those of
kino.
=BUTTER.= [Eng., Ger.] _Syn._ BUTY'RUM, L.; BEURRE, Fr.; BUTER, BUTERA,
Sax. The fatty matter obtained from cream by churning it.
_Manuf._ The process of making butter by the common operation of churning
is extremely simple, and is well known. The chief objects to attend to are
maintaining a proper temperature, and a certain degree of exposure to the
air. Extreme cleanliness must also be observed; the churn and other
utensils being frequently scalded out with water. When the butter is
'come,' it should be put into a fresh-scalded pan, or tub, which has been
standing in cold water, cold water poured on it, and after it has acquired
some hardness, it should be well beaten with a flat board until not the
least taste of the butter-milk remains, and the water, which must be often
changed, becomes quite colourless and tasteless. A little salt may then be
worked into it; after which it may be weighed and made into 'forms,' which
should then be thrown into cold water contained in an earthen pan provided
with a cover. In this way nice and cool butter may be obtained in the
hottest weather.
At Dumbarton the newly separated butter is put into a clean vessel, and a
corn sickle is drawn several times crosswise through it, to extract any
hairs that may adhere to it. This operation is performed in very cold
spring water, and is followed by thoroughly washing it therein. 10 oz. of
salt are now added to every stone-weight of the butter, and well mixed in.
In Devonshire the milk is generally scalded in copper pans over a charcoal
or wood fire, and the cream collected as soon as it rises, or, and more
frequently, when the whole has got cold. It is then churned in the usual
way. On the small scale the butter is commonly obtained from this cream by
patiently working it with the hand in a shallow pan or tub. Without care
the cream is apt to absorb some of the fumes from the charcoal, which
impart a peculiar taste to the butter. This is the reason why some of the
Devonshire butter has a slight smoky flavour. It may be removed by
thorough washing in cold water. Of late years, in the large dairy-farms of
Devonshire, covered flues, with openings to receive the bottoms of the
pans, have superseded open fires, by which the danger of contamination
from the fumes is removed.
_Choice._ Fresh butter has a pleasant odour and is of an equal colour
throughout its substance. If it smells sour, the butter-milk has not been
well washed out; and if it is streaked or veiny, it is probably mixed with
stale butter or lard. A good way to try butter is to thrust a knife into
it, which should not smell rancid and unpleasant when withdrawn. Rancid
and stale butter, when eaten in quantity, is capable of producing
dangerous symptoms.
_Pur._ The cheaper kinds of butter are frequently adulterated with common
wheat-flour, oatmeal, pea-flour, lard, and is sometimes mixed with suet
and turnips, as well as with a large quantity of salt and water. The trick
is concocted between the Irish factors and the London dealers. The higher
priced article is seldom mixed with anything beyond an excess of salt and
water, notwithstanding the assertions of alarmists to the contrary. The
presence of lard may be detected by the flavour and paleness of the
colour. A little of the sample adulterated with the other substances
named, if melted in a glass tube or phial, will separate into strata,
which are very marked when cold.
_Quantitative Analysis of Butter._--1. The following process for the
analysis of butter, by Mr A. H. Allen, is extracted from the 'Chemical
News' (xxxii, 77):--The Society of Public Analysts has adopted 80·00 per
cent. as the lowest limit of fat contained in a genuine butter.
The amount of water is best ascertained by heating 5 grams of the butter
in a small weighed beaker to a temperature of about 110° or 120° C. for an
hour or so. Some chemists merely heat the butter on a water bath.
According to the author's experience, perfect drying is next to impossible
at that temperature.
The dried butter is next treated in the beaker with anhydrous ether, or
commercial benzoline. The former liquid is expensive and inconveniently
volatile, while it must be used in a perfectly anhydrous condition (to
avoid solution of the salt), and except when boiling has but a limited
solvent power for butter, especially when adulterated. Benzoline dissolves
fat more readily than ether; it does not volatilise so rapidly at ordinary
temperatures, it is always anhydrous and has the advantage of low price.
The "benzoline" employed by the author is made by redistilling the
commercial article from a retort immersed in a bath of boiling water.
About one third of the original bulk usually comes over readily at 100°
C., and has a gravity of 0·689.
On warming the beaker containing the benzoline the dry butter readily
dissolves. The liquid is poured on a small dry filter and washed with warm
benzoline, the filtrate being collected in a small wide beaker. If the
filter had been previously weighed, its increase of weight, after careful
drying, will of course give the quantity of curd and salt in the 5 grams
of butter taken. Except in cases in which extreme accuracy is desired, it
is preferable to scrape the residue off the filter and weigh it
separately.
The error (owing to imperfect removal) only amounts to one or two tenths
per cent. of the butter taken. As the salt is accurately estimated
afterwards, the loss falls on the curd. The salt may be determined by
careful ignition of the filter and residue, the incombustible matter
consisting almost wholly of common salt, while the curd is ascertained by
loss of weight. This method is not to be recommended; for without great
care some of the salt will be volatilised and lost, the error causing the
amount of curd to appear excessive.
Ignition also renders any further examination of the curd an
impossibility. A far preferable plan is to return the weighed curd and
salt to the filter, and to wash them with cold water. The filtrate is made
up to 100 c. c., and the salt is estimated in a half of it by titrating
with decinormal nitrate of silver. The remaining portion of the solution
can be employed for the estimation of sugar, if desired. This is effected
by inverse titration with Fehling's copper solution, in the same way as
grape sugar. The estimation of sugar may sometimes be of interest, as a
means of ascertaining whether the aqueous portion of the butter consisted
of mere water or of serum of milk. In other words, the estimation of the
sugar may furnish a means of ascertaining whether an excess of water in
the butter is due to insufficient removal of the butter-milk, or to
subsequent incorporation of water. Every 0·001 gram of milk sugar
represents about 0·022 of average milk serum.
The residue insoluble in cold water usually consists almost wholly of
casein. If, however, the butter has been adulterated with mashed potatoes,
flour, or other starchy matters--said to be occasionally employed--they
will be found here. The presence of starch in the residue will, of course,
be readily indicated by treating it with hot water, and testing the cooled
liquid with solution of iodine. By pressing out a small portion of the
butter between two slips of glass, so as to obtain a thin film, and
observing it under the microscope (or by observing the caseous residue
after treatment with cold water), the nature of the starch may be
ascertained.
The solution of the fatty matter in benzoline is evaporated at 100° C.
till it no longer decreases in weight. The average proportion of fatty
matter in butter is about 85 per cent. If less than 80 per cent. the
butter must be considered adulterated. It is evident that a careful
estimation of the per-centage of fatty matter would often render separate
estimations of the water, curd, and salt unnecessary; for unless the sum
of the three latter constituents exceeded 20 per cent. the butter could
not be considered as adulterated, unless by an admixture of other fats.
An easy and rapid method of estimating the fat in the undried butter is
therefore a great desideratum; but unfortunately no satisfactory method is
at present known. The indirect estimation of the fat, by subtracting the
sum of the per-centages of water, curd, and salt from 100·00, ought to
agree with the direct estimation of fat within 0·5 per cent., and the
variation is often much less.
2. Dr Dupré adopts the following method: About 5 grams of the dry filtered
butter fat are weighed in a small strong flask; 25 c. c. of a normal
alcoholic soda solution are added; the flask is closed by means of a
well-fitting cauotchouc stopper, firmly secured by a piece of canvas and
string, and heated in a water-bath for about an hour. When cool the flask
is opened, the contents--which are semi-solid--carefully liquefied by
heat, and washed into a flask with hot water. This flask is now heated for
some time on a water-bath to expel the alcohol, some more hot water is
added, and 25 c. c. of diluted sulphuric acid somewhat stronger than the
alkali used, are run in. The contents are allowed to cool, and the acid
aqueous solution below the cake of fatty acids is passed through a filter.
The fatty acids in the flask are washed by hot water in the manner
recommended by Dr Muter, _i.e._, each time allowed to cool; all the
washings are passed through a filter.
The author uses no cambric, but passes everything through paper. With care
scarcely any of the fatty acid will find its way into the filter. After
the washing with water is completed and the flask drained, he washes any
fatty acid that may be on the filter into the flask by means of a mixture
of alcohol and ether on a water bath, and finally dries the fatty acids in
the flask at a temperature of 105° C. The drying can be done readily if
the melted fat is now and then shaken briskly, so as to subdivide the
water as much as possible. In this way the acids when once in the flask
are not taken out until their weight has been taken, thus reducing the
risk of loss to a minimum. Meanwhile the acidity of the aqueous filtrate
and washings is estimated by decinormal soda solution. Subtracting from
the amount required to the proportion necessary to neutralise the excess
of acid added in decomposing the soap, the rest represents the soluble
fatty acids contained in the butter taken, and on the assumption of its
being butyric acid, we can, of course, calculate the amount of this acid
present. When once the equivalent of the soluble acids present in butter
is fairly determined, this, of course, will have to be substituted for
that of butyric acid. The results thus obtained are very accurate, and the
process is very simple in execution.
The author has satisfied himself by repeated experiments that the
alkalinity of the alcoholic soda solution by itself is not altered by the
process. The author places no reliance on the specific gravity test, as he
finds that mutton dripping, and other fats likely to be used as
adulterants of butter, may acquire a specific gravity above ·911 by being
strongly and repeatedly heated. He thinks, however, that any sample of
butter below ·911 may safely be pronounced adulterated.
In a subsequent note Dr Dupré states that he has effected the
saponification, decomposition of the soap, and the washing and drying of
the fatty acids at ordinary temperature, thus still further reducing the
risk of breaking up the higher into lower acids. The saponification is
readily effected by using a sufficiency of alcoholic soda. Between four
and five grams of the dry butter fat were shaken up for several minutes
with 100 c. c. of normal alcoholic soda. The butter soon dissolves, but
after a time the solution gelatinises to a clear transparent mass. (The
temperature of the laboratory at the time of these experiments ranged
between 22° and 50°.) This jelly is now allowed to stand over night,
during which time the smell of butyric ether, very strong at first,
entirely disappears. In one of the experiments the alcohol was allowed to
evaporate spontaneously before the acid was added; in the other (made with
a different sample of butter) the soap was dissolved in about half a litre
of water, and at once decomposed by the addition of hydrochloric acid.
The fatty acids which separated in white curdy masses were thoroughly
washed on a filter with cold water, about four litres, dried in vacuo over
oil of vitriol, and weighed. The results of experiment show that butter
fat yields the same proportion of insoluble fatty acids when saponified
with or without the aid of heat.
3. Mr Gatehouse. _Rapid Method of Detecting the Adulteration of Butter
with other Fats._ The following comparative method is based upon the
insolubility of potassium stearate in alkaline solutions when the stearate
has been produced at high temperatures:
Before applying the test it is essential to remove all curd, butter-milk,
and salt, by washing with hot water or dissolving in ether. Twenty grains
of the butter are placed in a large test-tube one third full with water
boiled thoroughly and allowed to stand till the fat separates. The fat is
either dissolved in ether, and after evaporation saponified, or the lower
layer of the liquid is drawn off by a pipette as follows:--A thin glass
tube is drawn out to a fairly fine point and bent at the top to an obtuse
angle. Whilst the butter is still liquid this nozzle is inserted into the
bottom of the test-tube, placing the finger over the upper end to prevent
any liquid from getting in till it reaches the bottom. When fairly cold
the liquid may be withdrawn by a pipette attached to the tube. This
process can be repeated till the washings are free from chlorides.
The saponification is effected by heating the purified butter with 1/3-1/2
of its own weight of pure solid potassium hydrate (purified by alcohol) to
a temperature above 420° F.; applying the heat gently at first, and when
the frothing ceases, heating it more strongly, till no further apparent
action occurs. The ultimate temperature during saponification must be kept
above 400° for some minutes, otherwise the sterate formed will be soluble
instead of insoluble in the alkaline solution.
If the butter is pure, the colour of the residue will be at the utmost
light yellow, but should the butter be adulterated to any extent, it may
be almost black. Too much reliance must not, however, be placed on the
colour.
After allowing the tube and its contents to cool, the mass is boiled with
successive portions of distilled water till 6 oz. (or 200 c. c.)
altogether have been used. If the butter is pure, a portion of this
solution poured into a test-tube will present only a faint opalescence;
if, on the other hand, the butter is impure, a decided opacity will be
perceived, the degree depending upon the amount of adulteration.
The amount of adulteration in any sample is determined by first obtaining
pure butter and adding to separate portions of it known per-centages of
lard, &c. Each of these can be saponified as stated above; they are then
corked up in tubes of equal diameter and labelled with the per-centage of
lard they contain. On comparing them it will be seen that 2 per cent. of
lard can be clearly indicated.
When a butter is analysed all that is wanted is to saponify, make up to
the correct strength, and after cooling pour into a test-tube and compare
with the specimen tubes.
4. Dr Redwood. _The Determination of the Melting Points of Butter and
other Fats._ The apparatus in the form best suited for general use
consists of a basin, two small beakers, and a thermometer. The author uses
an enamelled iron basin about six inches in diameter, and three and a half
inches deep. In this is placed a beaker four and a half inches deep and
three inches in diameter, and within this beaker is placed another much
smaller one, supported by its projecting rim on a disk of tinplate or
copper, the outer edge of which rests on the mouth of the larger beaker.
Some mercury is put in the smaller beaker to the depth of about an inch,
and cold water into the larger beaker, so that its surface shall be half
an inch or an inch higher than that of the mercury.
A small drop of the fat which has been previously melted and heated to
several degrees above its melting-point, but has been allowed to cool
again to near its setting point, is put on the surface of the cold
mercury. This is best done by means of a thin glass rod about one eighth
of an inch in diameter, the end of which has been rounded off in the
blow-pipe flame.
It is important that the drop should be very small, and its temperature
when placed on the mercury not much above its melting point, for if it be
too hot it will spread over the surface of the mercury, which is not
desirable.
If the rounded end of the rod be slightly dipped into the melted fat, and
then brought to the surface of the mercury, a small hemispherical particle
will attach itself there and speedily congeal, becoming more or less
opaque in doing so. The weight of one of these hemispherical masses, which
should not be more than the eighth of an inch in diameter, will be from
1/50 to 1/10 of a grain. Having placed the drop of fat upon the mercury,
the bulb of a thermometer, with sufficiently minute graduations, is
introduced into the mercury and hot water poured into the basin. The heat
is thus communicated to the contents of the small beaker slowly through
the water in the larger beaker, and the rise of temperature in the mercury
may be easily regulated, and should take place at the rate of about one
degree per minute.
The mercury, by virtue of its comparatively good conducting power,
acquires a uniform temperature throughout, which is indicated by the
thermometer, and at the same time communicated to the fat. The fat when
the temperature approaches its melting point becomes partially
transparent, and if the stem or elongated bulb of the thermometer be now
brought up against it, the moment fusion takes place the liquid fat will
run into the channel formed by the repulsion of the mercury and the
outside of the thermometer tube. This process presents the following
advantages:--
1. The heat-conducting power of the mercury, on which the fat is placed,
ensures the equalisation of the temperature as indicated by the
thermometer, and at the same time communicated to the fat.
2. The direct contact of the fat with the mercury, without the
intervention of a bad conducting medium, such as glass, ensures a more
immediate and correct indication of the temperature at which liquefaction
takes place than would otherwise occur.
3. The minuteness of the quantity of fat operated upon reduces to a
minimum the time occupied in its melting, and thus facilitates the
determination with exactness of its melting point.
4. The time occupied in preparing small tubes and charging them with the
fat is saved, and several experiments in succession may be easily and
rapidly made with the same apparatus. The author observed that in butter
as well as other fats, such as tallows, there were at least two melting
points, dependent upon the way in which the fat had been previously
subjected to the action of heat, and that they may differ in butter to the
extent of 3° or 4° F.; the low melting point being that of the fat after
it has been heated to several degrees above its first melting point, and
the higher melting point being that of fat which has been previously
melted to the lowest possible temperature, and then immediately allowed to
congeal.
5. Professor Wanklyn carefully weighs one gram of butter, and heats it in
a platinum dish of the size shown in the accompanying figure, from four to
six hours or even more--in short, until it ceases to lose weight. The loss
of weight is the water, which should be calculated and expressed in
per-centages.
_Fat._ The dried butter is now to be heated with ether (the ether should
be made to boil by floating the dish in hot water). Several successive
portions should be taken, the whole passed through a filter, the filter
well washed with ether, and the filtrate evaporated to dryness and
weighed.
_Caseine and Ash._ The residue from which the fat and water have been
extracted is now to be taken, carefully weighed, then burned down to a low
red heat; the residue remaining is the ash, the loss the caseine.
[Illustration: Butter-analysing dish.]
The amount of ash, practically speaking, is the salt, but if there be any
doubt as to its composition, the chlorine maybe estimated by a volumetric
solution of nitrate of silver, and further examined.
The following table shows the composition of a few genuine and other
butters, examined according to the same, or at least to a similar process
to the one described:--
--------------------+------+-----------+------+--------+-----------------+------------------
| | Ash, | | | |
| Fat. |principally|Water.|Caseine.| Quality. |
| | Salt. | | | |
--------------------+------+-----------+------+--------+-----------------+------------------
Fresh Devonshire |82·7 | 1·1 |16·2 | 16·2 |Good. |WANKLYN.
butter. | | | | | |
Normandy butter. |82·1 | 1·8 |16·1 | 16·1 | " | "
Jersey butter. |78·491| 8·528 |10·445| 2·536 | " |ANGELL AND HEHNER.
Normandy butter. |82·643| 2·915 | 9·305| 5·137 | " |
Butter from Ventnor.|86·280| 6·600 | 3·831| 3·289 |Found to be | "
| | | | | adulterated |
| | | | | with foreign |
| | | | | fat. |
Butter from London. |87·50 | 1·559 |23·981| 6·880 |Adulterated with| "
| | | | | water. |
" " |47·119| 2·689 |42·358| 7·834 |Adulterated with | "
| | | | | water, and |
| | | | | contains an |
| | | | | excess of curd.|
--------------------+------+-----------+------+--------+-----------------+-----------------
6. _A Method of Detecting Meat Fats in Butter._ Mr Horsley, writing to the
'Chemical News,' September, 1874, says:--"My starting point is, that fresh
butter is permanently soluble in methylated ether, sp. gr. 0·730 at the
temperature of 65° Fahr. But with the view of seeing if any other
substance it may contain could be precipitated from it, I took, say, 20 or
25 grains of fresh butter, placed it in a small test-tube, and poured over
it one drachm of methylated ether, and on corking the tube it readily
dissolved after a few minutes' agitation. I then added 30 drops of
methylated alcohol, 63° o. p., and agitated again, but nothing was
precipitated. I, therefore, made another experiment with 15 grains of
butter and 10 grains of prepared mutton fat, dissolved them in 1 drachm of
ether first, and added 30 drops of alcohol, when in less than half an hour
the fat was precipitated in a room heated to 68° Fahr. Next, in order to
see the effects upon mixtures of known fats, such as lard, beef, mutton,
and tallow fats properly melted together in proportions of 60 grains of
butter and 40 of fat, and stirring till cold, I found that each of them
could, by a similar procedure, be precipitated in a few minutes. In one
case, that of mutton, I filtered off the ethereal liquid, and collected
the residue, and obtained as much as 30 per cent. of what had been used;
so that there is no longer any doubt about easily detecting fatty
adulterations in butter. Lastly, I would observe that crystallisation of
butter, out of the ethereal solution at a lower temperature than 65°, must
not be mistaken for the fats precipitated by alcohol alluded to, as the
butter, besides being so much lighter, occupies the upper layer, and is
different in character and easily remelted by the application of the warm
hand for a minute or so.
"Further experiments have proved that half an hour suffices to effect the
full precipitation of fats from the ethereal solutions by the addition of
20 drops or so of alcohol to the drachm of ether, containing not more than
25 grains of the adulterated butter; after which the tube should be
agitated and its contents projected on to a small double filter, washed
with a little alcohol, and the residue whilst moist scraped off, and
transferred to a watch-glass to dry. In this way loss by melting and
absorption into the paper is obviated.
"The following were the proportions of fats I recovered, viz.--
Lard 60 per cent.
Mutton fat 75 "
Beef fat 95 "
The precipitated mutton fat is powdery, and white as snow. Lard and beef
are more adherent and greasy; for that reason mutton makes the firmest
compound."
7. _On the Cooling of Fats._ At a meeting of the University of Edinburgh
Chemical Society, held on March 13th, 1878, a paper on the above subject
was read by Mr Treharne, M.B.C.M., wherein the author states:--"If equal
bulks of the fats of mutton, beef, pork, and butter, and palm oil be
heated to 100° C. in small flasks fitted with a thermometer through the
cork, and then allowed to cool by radiation under the same conditions for
each, temperature is found to fall regularly to a certain point (which is
different for each of the facts above named) and then to rise to a certain
turning point. These turning points are approximately as follows:--
For Mutton fat 40° C.
" Beef " 28·5° C.
" Pork " 26·5° "
" Butter " 23·5° "
" Palm oil 21·0° "
The extent of the rise in temperature is different in each fat, being
greatest in that of mutton, and least in that of butter and palm oil. The
extent of the rise is also greater within certain limits the greater the
quantity of fat employed; but as a rule the turning point is pretty
constant for the same fat. There is also a little difference in the
turning points and the extent of rise according to the part of the carcase
from which the fat has been taken. If temperature and time be taken as
co-ordinates, and the rate of cooling be represented by curves, these
latter will be characteristic of the respective fats. A mixture of equal
parts of mutton and butter fats does not give a curve intermediate between
those of its two components; but is such as to indicate that less heat is
given out on cooling (to 20° C say) than in the case of butter, which,
compared with mutton fat, gives off very little heat."
For further information on the subject of 'Butter' the reader is referred
to a Report by Mr Bell--the principal of the Chemical Laboratory at
Somerset House--to the Board of Inland Revenue, included in a return made
to the House of Commons in 1876.
_Preservation._ 1. Melt the butter in a stoneware or a well-glazed earthen
pan set in a water bath at a heat not exceeding 180° Fahr., and keep it
heated, skimming it from time to time until it becomes quite transparent;
then pour off the clear portion into another vessel, and cool it as
quickly as possible by placing the vessel in very cold water or ice. This
is the method employed by the Tartars who supply the Constantinople
market. In this state it may be preserved perfectly fresh for 6 or 9
months, if kept in a close vessel and a cool place. This is the plan so
strongly recommended by M. Thénard. Mr Eaton states that butter melted by
the Tartarian method, and then salted by ours, will keep good and
fine-tasted for two years.
2. Saltpetre and white sugar, of each 1 oz.; best Spanish great-salt (or
Cheshire large-grained salt), 2 oz.; all in very fine powder; mix
thoroughly, and add 1 oz. of this mixture to every lb. of butter, and
thoroughly incorporate them together. The butter thus prepared is then to
be tightly pressed into clean glazed earthenware vessels (or well-seasoned
casks), so as to leave no vacuities. This plan is recommended by Dr
Anderson, who declares that "butter so prepared will keep in a cool place
for years; and will bear a voyage to the East Indies, if packed (stowed)
so as not to melt." It does not taste well before it has stood for three
or four weeks, after which it acquires a rich marrow-like flavour, which
no other butter ever possesses. A good method to preserve the butter from
the air is to fill the pots to within an inch of the top, then to lay on
it some coarse-grained salt to the depth of a 1/4 to 1/2 an inch, and
lastly to cover each pot with a slate, plate, or other flat article. The
salt by long keeping runs to brine, which forms an air-tight layer on the
top of the butter, and may at any time be very easily removed by turning
the pot on one side.
3. Fresh butter, 21 lbs.; salt, 1 lb.; saltpetre, 1 oz. These are the
common proportions for the best salt butter of the shops.
4. Fresh butter, 18 lbs.; salt, 1 lb.; saltpetre, 1-1/2 oz.; honey or fine
brown sugar, 2 oz. Superior to No. 3.
_Concl. Remarks._ It may be useful to know that rancid butter may be
restored, or, in all cases, greatly improved, by melting it in a water
bath with some fresh-burnt and coarsely powdered animal charcoal (which
has been thoroughly freed from dust by sifting), and straining it through
clean flannel. A better and less troublesome method is to well wash the
butter first with some good new milk, and next with cold spring water.
Butyric acid, on the presence of which rancidity depends, is freely
soluble in fresh milk.
The turnip-flavour arising from the cows being fed on turnips or cabbages
is said to be removed by one or other of the following methods:--1. When
the milk is strained into the pans put to every 6 galls. 1 gal. of boiling
water.--2. Dissolve 1 oz. of nitre in a pint of spring water, and put a
1/4 pint of the solution to every 15 galls. of milk.--3. Keep back a 1/4
pint of the sour cream when you churn, and put it into a well-scalded pot,
into which you are to gather the next cream; stir that well, and do so
with every fresh addition. Each of these methods come on good authority,
but we are bound to say that our own experience does not confirm their
constant success. We have found that the addition of a handful of salt to
the water used to wash the butter is as good a plan as any.
=Butter, Ancho'vy.= From anchovies (boned and beaten to a paste), 1 part;
butter, 2 parts; spice, q. s.
=Butter-colouring= (from Paris). A mixture of 40 per cent. of chrome
yellow with some fat coloured with annatto. (Flückiger and Weil.)
=Butter, Clar'ified.= Fresh butter melted in a water bath, allowed to
settle, and the clear portion poured into an earthenware basin or pot, set
in cold water, so as to cool it as quickly as possible, without allowing
it to crystallise. It keeps a long time without becoming rank. See BUTTER,
No. 1 (_antè_).
=Butter, Hon'ey.= Fine Narbonne honey, 2 to 4 oz.; mixed with good butter,
1 lb. Used as a delicacy for children, and by the sick and aged.
=Butter, Lem'on.= See BUTTER, ORANGE.
=Butter, Melt'ed.= This well-known sauce may be prepared of excellent
quality as follows:--Beat up about 1 oz. of fine flour with 4 oz. of
butter, in the cold, until they are evenly and thoroughly mixed, then add
4 or 5 table-spoonfuls of hot milk, put the whole into a small saucepan,
and continue shaking it, all in one direction, until it simmers very
gently; lastly, remove it from the fire, and pour it into the butter-boats
for use. These last should be filled with hot water, and then emptied and
wiped dry, before putting the melted butter into them. See SAUCES.
=Butter, Or'ange.= _Prep._ 1. From 6 eggs, 2 oz. of powdered sugar, and 4
oz. of butter, well beaten together with a little orange-flower water.
Sometimes 1 or 2 oz. of blanched almonds, or of almond-paste, is added.
2. Butter, 1 lb.; syrup of orange peel, 4 oz. Both are eaten as a
delicacy. LEMON BUTTER, is made in a similar manner.
=Butter of An'timony*[double-dagger].= Trichloride of antimony.
=Butter of Caca'o.= See CO'COA, and CO'COA-NUT OIL.
=Butter of Nut'megs.= Collected from the surface of the water in the
still, after the distillation of the essential oil of nutmegs.
=Butter of Ro'ses.= Obtained by distilling damask roses. It separates
slowly from the water in the receiver. It has little smell, and is hence
used to dilute the odour of musk, ambergris, and civet.
=Butter of Wax.= Prepared by distilling bees'-wax. A factitious kind is
also made.
=Butter of Zinc*[double-dagger].= Chloride of zinc.
=Butter Powder= (from the Adler-Apotheke Emmerich on the Rhine).
Bicarbonate of soda. (Dr U. Kreusler.)
=Butter Powder= (Lemmel, Schleswig-Holstein). An impure bicarbonate of
soda, coloured with turmeric. (Hirschberg.)
=Butter Powder, Schuhrer's= (Emil Schührer, Mutzschen, Saxony). This, it
is claimed, will considerably increase the yield of butter, shorten the
process of churning, and yield a product which will be firm even in the
height of summer, well-flavoured, of a handsome colour, and of excellent
commercial value. It consists of a tolerably pure commercial bicarbonate
of soda, with 1/2 per cent. of powdered turmeric. (Dr Peters.)
=Butter Powder, Tomlinson's= (Tomlinson & Co., Lincoln, England). Ordinary
bicarbonate of soda, coloured with 3/4 per cent. of annatto. (Dr
Karmrodt.)
=Butter-preservative Paste= (from Spaa). Consists of common salt, 52
parts; nitre, 23 parts; syrup, 5 parts. (Wittstein.)
=BUTTERINE.= A substance known under this name, and intended as a
substitute for butter, is imported into this country from New York.
Of butterine Dr CAMPBELL BROWN remarks:--"In general appearance, taste,
and consistence, it is very similar to ordinary butter; but
notwithstanding that its solidifying point is lower than that of some
butters, it retains much of the peculiar crumbly texture and fracture of
dripping.
"It softens at 78° F., and melts at 86°. When heated and slowly cooled it
obscures the thermometer at 62° and solidifies at 60°. It contains--
Water 11·25 to 8·5
Salt 1·03 " 5·5
Curd 0·57 " 0·6
Fat 87·15 " 85·4
------ ------
100·00 100·00
"The fat consists of oleine, palmitine, margarine, a trace of stearine,
and about 5 or 6 per cent. of butter. When dissolved in about four times
its weight of ether, and allowed to evaporate spontaneously, it does not
deposit any fat until more than half of the ether has passed off, and if
the temperature is not below 60° the deposit is not solid.
"The first deposit when dried fuses at 108°; the second deposit fuses at
88°, and solidifies at 64°.
"Under the microscope butterine does not appear to consist of acicular
crystals of fat, but of irregular masses, containing a few butter
globules, particles of curd, and crystals of salt. With polarised light
the irregular crystalline structure is beautifully seen, and is clearly
distinguishable from butter which has been melted and recongealed. When
old and rancid it acquires the odour and taste of dripping, but it keeps
longer undecomposed than butter. When fresh it is a wholesome substitute
for real butter. No one can reasonably take exception to its sale.
"Butterine may be detected by the following characters:--
"1. Its crumbly fracture.
"2. Its loss of colour when kept melted for a short time at 212°.
"3. The behaviour of its ethereal solution.
"4. Its action on polarised light."
The 'American Chemist' for 1876 contains an interesting paper by Mr Henry
Mott on the manufacture of artificial butter, which is too lengthy for
insertion here.
=BUTTER-MILK.= The liquid that remains after the butter is separated from
the cream.
_Qual., &c._ Butter-milk left from the churning of sweet cream is not only
very delicious, but exceedingly wholesome and nutritious. It is eaten with
fruit, puddings, and cakes, and is said to possess the property of
allaying the nervous irritability induced by excessive tea-drinking. It is
an admirable beverage in rickets, diabetes, and many stomach affections.
An American physician has recently asserted that it induces longevity. See
MILK.
=BUTTONS.= See BRASS, GILDING, &c.
=BU'TYRATE.= [Eng., Fr.] _Syn._ BU'TYRAS, L. A salt in which the hydrogen
of butyric acid is replaced by a basic radical.
=Butyrate of Barium.= _Prep._ Saponify butter with a boiling solution of
caustic alkali, and decompose the resulting soap by adding a solution of
tartaric acid; filter and distil; neutralise the distillate with hydrate
of barium, and evaporate; the first crystals that form are caprate of
barium; the next, caproate of barium; and the last, butyrate of barium.
This salt is very soluble in water, and hence is easily separated from the
others.--_Use._ Chiefly for making butyric acid.
=BUTYRIC= (-t[)i]r'-). _Syn._ BUTYR'ICUS, L.; BUTYRIQUE, Fr. Of or from
butter.
=BUTYRIC ACID.= HC_{4}H_{7}O_{2}. _Syn._ ACIDUM BUT[)Y]R'ICUM, L.; ACIDE
BUTYRIQUE, Fr.; BUTTERSÄURE, Ger. An oily acid, first obtained by Chevreul
from butter.
_Prep._ From butyrate of barium or magnesium, by adding sulphuric acid in
quantity not quite sufficient to decompose the whole of the salt; the
clear liquid, filtered and distilled, yields butyric acid, from which the
water may be removed by digestion with chloride of calcium.
_Prop._ A thin colourless liquid, of pungent rancid odour, and sour taste,
miscible with water and alcohol. It boils and distils unchanged at 327°
Fahr. Sp. gr. ·963. See ETHERS.
=BU'TYRIN= (-in). [Eng., Fr.] An oily substance existing in butter, and of
which it forms the characteristic portion. It was discovered by Chevreul.
_Prep._ Keep clarified butter in a porcelain vessel, at a heat of 66°, for
some days; carefully collect the oily portion which separates, mix it with
an equal weight of alcohol of the sp. gr. ·796, and agitate it frequently
for 24 hours; after repose pour off the clear portion, and evaporate it;
treat the oily residuum with a little carbonate of magnesium, to remove
free acid, and wash off the butyrate of magnesium, thus formed, with
water; lastly, heat the remaining fatty matter in alcohol, filter, and
evaporate, by a gentle heat; the residuum is butyrin.
=BUXINE= (-[)i]n). A substance detected by M. Faure in _bux'us
semper'virens_, or the common box-tree.
=CABBAGE.= _Syn._ BRAS'SICA, L.; CHOU, Fr.; KOHL, Ger. This common
esculent, and all its numerous varieties, are merely cultivated specimens
of the wild sea-cabbage of our coasts (_bras'sica olera'cea_, Linn.), one
of an extensive and valuable genus of plants belonging to the nat. ord.
Cruciferæ. After the potato, the cabbage is doubtless more extensively
used by the masses of the people than any other fresh vegetable. When
young, and properly dressed, it forms an agreeable and wholesome addition
to animal food, the grossness of which, it is said, it tends to correct.
It should be eaten only when fresh gathered and fresh cooked; and the
unconsumed portion, as well as the water in which it has been boiled,
should be at once thrown away. Persons troubled with a weak digestion, or
who have a tendency to flatulence, diarrh[oe]a, or worms, would do well to
avoid them. Their use is particularly serviceable in scurvy, and in
numerous skin diseases.
It has been asserted that cabbages, cauliflowers, broccoli, celery, and
several other culinary vegetables, may be preserved in a fresh state for
some time, by cutting them so that they may have about two inches of stem
left below the leaves, scooping out the pith as far down as a small knife
will reach, and then suspending them perpendicularly by means of a cord,
in an inverted position, in some cool situation, and daily filling up the
bottom part of the stem with clean cold water. In this way it is stated
that a supply of green vegetables may be readily obtained during a severe
winter, and on ship-board. Other methods, including those usually adopted
with the same object, are noticed under VEGETABLES (Culinary).
Cabbages, broccoli, &c., are dressed by simply throwing them into boiling
water, and simmering them until tender. A few minutes is sufficient for
this purpose. A pinch of salt of tartar, or of carbonate of soda, is
commonly added to the water, to preserve the green colour of the
vegetables.
=CACHOU AROMATISE= (k[)a]shoo [)a]r[)o]m[)a]t[=e]z[=a]). [Fr.] A
mouth-lozenge intended to sweeten and perfume the breath. Preparations of
this description are much used by smokers and bacchanals. The form under
which they are generally prepared for sale is that of 1-1/2 to 2 gr.
pills, neatly silvered. Originally they were composed chiefly of catechu
and sugar, flavoured and perfumed with the stronger aromatics; but at the
present day the catechu, from which they derive their name, is not
unfrequently omitted. Their preparation is described elsewhere. See
BREATH, LOZENGES, PASTILS, &c.
=CAD'MIUM.= Cd. [Eng., L.] _Syn._ KLAPRO'THIUM. A metal discovered by
Stromeyer and Hermann, in the ores of zinc.
_Prep._ 1. (Stromeyer.) The cadmo-zincic ore is dissolved in an excess of
dilute sulphuric or hydrochloric acid by heat; a stream of sulphuretted
hydrogen is passed through the solution, the resulting precipitate
(sulphide of cadmium) dissolved in nitric acid, and the solution
evaporated to dryness; the residuum is dissolved in water, the solution
precipitated with carbonate of ammonium in excess, and the precipitate
(carbonate of cadmium) collected, mixed with charcoal, and heated to
redness in a crucible apparatus so arranged as to condense the fumes; the
cadmium sublimes.
2. (Wollaston.) A solution of the ore obtained as above is placed in a
platinum capsule, and a piece of metallic zinc is plunged into it. In a
short time the cadmium is precipitated, and attaches itself to the sides
of the capsule, when it is collected, washed, and dried.
3. (Herapath.) When zinc is obtained by distilling its ores, per
descensum, the first portion of the metallic fumes evolved burn with a
brownish flame, and deposit oxide of cadmium, which is subsequently
reduced by distillation with charcoal. Thousands of pounds of cadmium are
yearly wasted at the zinc works which might be easily collected in a
similar manner.
_Prop., &c._ Resembles tin in most of its physical properties, being
white, soft, and malleable. Sp. gr. 8·61. Stromeyer gives its melting
point as 442° Fahr., but Dr Wood, an American chemist, states that the
metal requires for its fusion nearly the same heat as lead, and gives it
as about 600° Fahr. It volatilises at a somewhat higher temperature,
giving off orange-coloured, suffocating fumes, which, when inhaled too
freely, leave a disagreeable, sweetish, styptic sensation upon the lips,
and a persistent brassy taste in the mouth, with constriction of the
throat, heaviness in the head, and nausea. The alloys of cadmium are said
to be brittle by almost all who have treated of them, but Wood found that
many were extremely tenacious, as, for instance, the combination of 2
parts of silver and 1 part of cadmium, which is perfectly malleable and
very strong. The amalgam of equal parts of cadmium and mercury is also
highly malleable. Like bismuth, cadmium has the property of promoting
fusibility in certain alloys; thus, a remarkable fusible metal may be
formed by melting together cadmium 1 to 2 parts, lead 2 parts, and tin 4
parts.
_Tests._ Its ores and salts are recognised as follows:--1. Mixed with
carbonate of sodium, and exposed on a charcoal support to the reducing
flame of the blowpipe, the charcoal becomes almost instantly covered with
a reddish-yellow incrustation of oxide of cadmium, commonly forming a
circle or zone.--2. Caustic soda and potassa give a white precipitate
(hydrated oxide) in solutions containing cadmium, insoluble in excess of
the precipitant.--3. Ammonia gives a similar white precipitate, freely
soluble in excess.--4. The alkaline carbonates give white precipitates
(carbonate of cadmium), insoluble in excess.--5. Sulphuretted hydrogen,
and sulphydrate of ammonium, give a bright yellow precipitate (sulphide of
cadmium), which is insoluble in dilute acid, alkalies, sulphides, and
cyanide of potassium, but readily soluble in both hydrochloric acid and
nitric acid, especially with heat.--6. The salts of cadmium are readily
distinguished from those of arsenic, by the precipitated sulphide being
insoluble in ammonia, and soluble in hydrochloric acid, and being capable
of sustaining a white heat without subliming.
=Cadmium, Car'bonate of.= CdCO_{3}. _Syn._ CAD'MII CAR'BONAS, L. From a
solution of sulphate or chloride of cadmium, and an alkaline carbonate;
the precipitate being collected, washed, and dried by a gentle heat. A
white powder.
=Cadmium, Chlo''ride of.= CdCl_{2}. _Syn._ HYDROCHLO''RATE OF CADMIUM,
MU''RIATE OF CADMIUM; CAD'MII CHLORI'DUM, CAD'MII HYDROCHLO''RAS, L.
_Prep._ 1. (Pure.) By dissolving carbonate or oxide of cadmium in
hydrochloric acid, and crystallising by gentle evaporation. Prismatic
crystals; very soluble in water.
2. (Turner.) By exposing the product of the last process to heat.
Amorphous.