grease layer. The whole coin is greased slightly and then carefully
wiped off again with a little wadding, but in such a manner {468} that
a thin film of grease remains on the surface. Next, a ring of strong
cardboard or thin pasteboard is placed around the edge, and the ends
are sealed together. Now stir up a little gypsum in a small dish and
put a teaspoonful of it on the surface of which the mold is to be
taken, distributing it carefully with a badger’s-hair brush, entering
the finest cavities, which operation will be assisted by blowing on it.
When the object is covered with a thin layer of plaster of Paris, the
plaster, which has meanwhile become somewhat stiffer, is poured on, so
that the thickness of the mold will be about 1/20 of an inch. The
removal of the cast can be effected only after a time, when the plaster
has become warm, has cooled again, and has thoroughly hardened. If it
be attempted to remove the cast from the metal too early and by the use
of force, fine pieces are liable to break off and remain adhering to
the model. In order to obtain a positive mold from the concave one, it
is laid in water for a short time, so that it becomes saturated with
the water it absorbs. The dripping, wet mold is again provided with
an edge, and plaster of Paris is poured on. The latter readily flows
out on the wet surface, and only in rare cases blisters will form.
Naturally this casting method will furnish a surface of pure gypsum,
which is not the case if the plaster is poured into a greased mold.
In this case the surface of the cast contains a soapy layer, for the
liquid plaster forms with oil a subsequently rather hard lime soap. The
freshly cast plaster must likewise be taken off only when a quarter of
an hour has elapsed, after it has become heated and has cooled again.
MATS FOR METALS: See Metals.
«MATZOON.»
Add 2 tablespoonfuls of bakers’ yeast to 1 pint of rich milk, which
has been slightly warmed, stirring well together and setting aside in
a warm room in a pitcher covered with a wet cloth for a time varying
from 6 to 12 hours, according to the season or temperature of the room.
Take from this, when curdled, 6 tablespoonfuls, add to another pint of
milk, and again ferment as before, and continue for five successive
fermentations in all, when the product will have become free from the
taste of the yeast. As soon as the milk thickens, which is finally
to be kept for use, it should be stirred again and then put into a
refrigerator to prevent further fermentation. It should be smooth, of
the consistence of thick cream, and of a slightly acid taste.
The milk should be prepared fresh every day, and the new supply is made
by adding 6 tablespoonfuls of the previous day’s lot to a pint of milk
and proceeding as before.
The curd is to be eaten with a spoon, not drunk, and preferably with
some bread broken into it. It is also sometimes eaten with sugar, which
is said not to impair its digestibility.
MAY WINE: See Wines and Liquors.
«MEAD.»
In its best form Mead is made as follows: 12 gallons of pure, soft
water (clean rain water is, next to distilled water, best) are mixed
with 30 gallons of expressed honey in a big caldron, 4 ounces of hops
added, and the whole brought to a boil. The boiling is continued with
diligent skimming, for at least an hour and a half. The fire is then
drawn, and the liquid allowed to cool down slowly. When cold, it is
drawn off into a clean barrel, which it should fill to the bung,
with a little over. A pint of fresh wine yeast or ferment is added,
and the barrel put in a moderately warm place, with the bung left
out, to ferment for from 8 to 14 days, according to the weather (the
warmer it is the shorter the period occupied in the primary or chief
fermentation). Every day the foam escaping from the bung should be
carefully skimmed off, and every 2 or 3 days there should be added
a little honey and water to keep the barrel quite full, and in the
meantime a pan or cup should be inverted over the hole, to keep out
dust, insects, etc. When fermentation ceases, the procedure varies.
Some merely drive in the bung securely and let the liquor stand for a
few weeks, then bottle; but the best German makers proceed as follows,
this being a far superior process: The liquor is removed from the
barrel in which it fermented to another, clean, barrel, being strained
through a haircloth sieve to prevent the admission of the old yeast.
A second portion of yeast is added, and the liquid allowed to pass
through the secondary fermentation, lasting usually as long as the
first. The bung is driven into the barrel, the liquid allowed to stand
a few days to settle thoroughly and then drawn off into bottles and
stored in the usual way. Some add nutmeg, cinnamon, etc., prior to the
last fermentation. {469}
MEASURES: See Weights and Measures.
MEASURES, TO CLEAN: See Cleaning Preparations and Methods.
MEAT EXTRACT CONTAINING ALBUMEN: See Foods.
MEAT PEPTONOIDS: See Peptonoids.
MEAT PRESERVATIVES: See Foods.
MEAT PRODUCTS (ADULTERATED): See Foods.
MEDAL IMPRESSIONS: See Matrix Mass.
MEDALS, CLEANING AND PRESERVING: See Cleaning Compounds.
MEDALLION METAL: See Alloys.
MEDICINE DOSES: See Doses.
«MEERSCHAUM:»
«To Color a Meerschaum Pipe.»—I.—Fill the pipe and smoke down about
one-third, or to the height to which you wish to color. Leave the
remainder of the tobacco in the pipe, and do not empty or disturb it
for several weeks, or until the desired color is obtained. When smoking
put fresh tobacco on the top and smoke to the same level. A new pipe
should never be smoked outdoors in extremely cold weather.
II.—The pipe is boiled in a preparation of wax, 8 parts; olive oil, 2
parts; and nicotine, 1 part, for 10 or 15 minutes. The pipe absorbs
this, and a thin coating of wax is held on the surface of the pipe,
and made to take a high polish. Under the wax is retained the oil of
tobacco, which is absorbed by the pipe; and its hue grows darker in
proportion to the tobacco used. A meerschaum pipe at first should be
smoked very slowly, and before a second bowlful is lighted the pipe
should cool off. This is to keep the wax as far up on the bowl as
possible; rapid smoking will overheat, driving the wax off and leaving
the pipe dry and raw.
«To Repair Meerschaum Pipes.»—To cement meerschaum pipes, make a glue
of finely powdered and sifted chalk and white of egg. Put a little of
this glue on the parts to be repaired and hold them pressed together
for a moment.
See also Adhesives under Cements.
«To Tell Genuine Meerschaum.»—For the purpose of distinguishing
imitation meerschaum from the true article, rub with silver. If the
silver leaves lead pencil-like marks on the mass, it is not genuine but
artificial meerschaum. If no such lines are produced, the article is
genuine.
MENTHOL COUGH DROPS: See Confectionery.
MENTHOL TOOTH POWDER: See Dentifrices.
MERCURY SALVES: See Ointments.
MERCURY STAINS, TO REMOVE: See Cleaning Preparations and Methods.
METACARBOL DEVELOPER: See Photography.
«Metals and Their Treatment»
METAL CEMENTS: See Adhesives and Lutes.
METAL CLEANING: See Cleaning Preparations and Methods.
METAL INLAYING: See Damaskeening.
METAL POLISHES: See Polishes.
METAL PROTECTIVES: See Rust Preventives.
METAL VARNISHES: See Varnishes.
METALS, HOW TO ATTACH TO RUBBER: See Adhesives, under Rubber Cements.
METALS, SECURING WOOD TO: See Adhesives.
«METALS, BRIGHTENING AND DEADENING, BY DIPPING:»
«Brightening Pickle.»—To brighten articles by dipping, the dipping
liquid must not be too hot, otherwise the pickled surface turns dull;
neither must it be prepared too thin, nor must wet articles be entered,
else only tarnished surfaces will be obtained.
For a burnish-dip any aqua fortis over 33° Bé., i. e., possessing a
specific gravity of 1.30, may be employed. It is advisable not to use
highly concentrated aqua fortis, to reduce the danger of obtaining
matt work. It is important that the quantity of oil of vitriol, which
is added, {470} is correct. It is added because the action of the aqua
fortis is very uncertain. Within a short time it becomes so heated in
acting on the metals that it turns out only dull work, and pores or
even holes are apt to be the result of the violent chemical action.
If the aqua fortis is diluted with water the articles do not become
bright, but tarnish. For this reason sulphuric acid should be used.
This does not attack the metals; it only dilutes the aqua fortis and
distributes the heat generated in pickling over a larger space. It
is also much cheaper, and it absorbs water from the aqua fortis and,
therefore, keeps it in a concentrated state and yet distributed over
the space.
In the case of too much oil of vitriol the dilution becomes too great
and the goods are tarnished; if too little is added, the mixture soon
ceases to turn out bright articles, because of overheating. On this
experience are based the formulas given below.
Dip the articles, which must be free from grease, into the pickle,
after they have been either annealed and quenched in diluted sulphuric
acid or washed out with benzine. Leave them in the dipping mixture
until they become covered with a greenish froth. Then quickly immerse
them in a vessel containing plenty of water, and wash them out well
with running water. Before entering the dipped articles in the baths
it is well to remove all traces of acid, by passing them through a weak
soda or potassium cyanide solution and washing them out again. If the
brightly dipped goods are to remain bright they must be coated with a
thin spirit or zapon lacquer.
Following are two formulas for the pickle:
I.—Aqua fortis, 36° Bé., by weight 100 parts
Oil of vitriol (sulphuric acid), 66° Bé., by weight 70 parts
Cooking salt, by volume 1 1/2 parts
Shining soot (lampblack), by volume 1 1/2 parts
II.—Aqua fortis, 40° Bé., by weight 100 parts
Oil of vitriol, 66° Bé., by weight 100 parts
Cooking salt, by volume 2 parts
Shining soot, by volume 2 parts
«Matting or Deadening Pickle.»—When, instead of brilliancy, a matted
appearance is desired for metals, the article is corroded either
mechanically or chemically. In the first case it is pierced with fine
holes near together, rubbed with emery powder or pumice stone and
tamponned. In the other case the corrosion is effected in acid baths
thus composed:
Nitric acid of 36° Bé., 200 parts, by volume; sulphuric acid of 56°
Bé., 200 parts, by volume; sea salt, 1 part, by volume; zinc sulphate,
1 to 5 parts, by volume.
With this proportion of acids the articles can remain from 5 to 20
minutes in the mixture cold; the prominence of the matt depends on
the length of time of the immersion. The pieces on being taken from
the bath have an earthy appearance which is lightened by dipping them
quickly in a brightening acid. If left too long the matted appearance
is destroyed.
«Cotton Matt.»—This matt, thus called on account of its soft shade, is
rarely employed except for articles of stamped brass, statuettes, or
small objects. As much zinc is dissolved in the bath as it will take.
The pieces are left in it from 15 to 30 minutes. On coming from the
bath they are dull, and to brighten them somewhat they are generally
dipped into acids as before described.
«Silver Matt.»—Articles of value for which gilding is desired are
matted by covering them with a light coating of silver by the battery.
It is known that this deposit is always matt, unless the bath contains
too large a quantity of potassium cyanide. A brilliant silvering can be
regularly obtained with electric baths only by adding carbon sulphide.
Four drachms are put in an emery flask containing a quart of the bath
fluid and allowed to rest for 24 hours, at the end of which a blackish
precipitate is formed. After decanting, a quart is poured into the
electric bath for each quart before every operation of silvering.
«Dangers of Dipping.»—The operation of dipping should be carried
out only in a place where the escaping fumes of hyponitric acid and
chlorine can pass off without molesting the workmen, e. g., under
a well-drawing chimney, preferably in a vapor chamber. If such an
arrangement is not present the operator should choose a draughty place
and protect himself from the fumes by tying a wet sponge under his
nose. The vapors are liable to produce very violent and dangerous
inflammations of the respiratory organs, coming on in a surprisingly
{471} quick manner after one has felt no previous injurious effect at
all.
«COLORING METALS:»
See also Plating.
«Processes by Oxidation.»—By heat:—Coloration of Steel.—The steel,
heated uniformly, is covered in the air with a pellicle of oxide and
has successively the following colors: Straw yellow, blue (480° to
570° F.), violet, purple, water-green, disappearance of the color;
lastly the steel reddens. For producing the blue readily, plunge
the object into a bath of 25 parts of lead and 1 part of tin; its
temperature is sufficient for bluing small pieces.
Bronzing of Steel.—I.—The piece to be bronzed is wet by the use of a
sponge with a solution formed of iron perchloride, cupric sulphate,
and a nitric acid. It is dried in a stove at 86° F., then kept for 20
minutes over boiling water. It is dried again at 86° F., and rubbed
with a scratch brush.
This operation is repeated several times.
Bronzing of Steel.—II.—Rust and grease are removed from the objects
with a paste of whiting and soda. They are immersed in a bath of dilute
sulphuric acid, and rubbed with very fine pumice-stone powder. They are
then exposed from 2 to 3 minutes to the vapor of a mixture of equal
parts of concentrated chlorhydric and nitric acids.
The object is heated to 570° to 660° F. until the bronze color appears.
When cooled, it is covered with paraffine or vaseline while rubbing,
and heated a second time until the vaseline or paraffine commences
to decompose. The operation is repeated. The shades obtained are
beautiful, and the bronzing is not changeable. By subjecting the object
to the vapors of the mixture of chlorhydric and nitric acids, shades
of a light reddish brown are obtained. By adding to these two acids
acetic acid, beautiful yellow bronze tints are procured. By varying
the proportion of these three acids, all the colors from light reddish
brown to deep brown, or from light yellow bronze to deep yellow bronze,
are produced at will.
Bronzing.—III.—Under the name of Tuker bronze, a colored metal is found
in trade which imitates ornamental bronze perfectly. It is obtained by
deoxidizing or, if preferred, by burnishing cast iron. A thin layer of
linseed oil or of linseed-oil varnish is spread on. It is heated at
a temperature sufficient for producing in the open air the oxidation
of the metal. The temperature is raised more or less, according as a
simple yellow coloration or a deep brown is desired.
Lustrous Black.—In a quantity of oil of turpentine, sulphuric acid is
poured drop by drop, stirring continually until a precipitate is no
longer formed. Then the whole is poured into water, shaken, decanted,
and the washing of the precipitate commenced again until blue litmus
paper immersed in the water is no longer reddened. The precipitate will
thus be completely freed from acid. After having drained it on a cloth,
it is ready for use. It is spread on the iron and burned at the fire.
If the precipitate spreads with difficulty over the metal, a little
turpentine can be added. It is afterwards rubbed with a linen rag,
soaked with linseed oil, until the surface assumes a beautiful lustrous
black. This covering is not liable to be detached.
Bluish Black.—Make a solution composed of nitric acid, 15 parts; cupric
sulphate, 8 parts; alcohol, 20 parts; and water, 125 parts. Spread over
the metal when well cleaned and grease removed. Dry and rub with linen
rag.
Black.—Make a solution composed of cupric sulphate, 80 parts; alcohol,
40 parts; ferric chloride, 30 parts; nitric acid, 20 parts; ether,
20 parts; water, 400 to 500 parts, and pass over the object to be
blackened.
Magnetic Oxide.—I.—A coating of magnetic oxide preserves from rust. To
obtain it, heat the object in a furnace to a temperature sufficient
to decompose steam. Then inject from 4 to 6 hours superheated steam
at 1,100° F. The thickness of the layer of oxide formed varies with
the duration of the operation. This process may replace zincking,
enameling, or tinning.
II.—A deposit of magnetic oxide may be obtained by electrolysis. The
iron object is placed at the anode in a bath of distilled water heated
to 176° F. The cathode is a plate of copper, or the vessel itself if
it is of iron or copper. By electrolysis a layer of magnetic oxide is
formed.
In the same way other peroxides may be deposited. With an alkaline
solution of litharge a brilliant black deposit of lead peroxide, very
adherent, is obtained.
The employment of too strong a current must be avoided. It will produce
a pulverulent deposit. To obtain a good coating, it is necessary after
leaving the objects for a moment at the opposite {472} pole, to place
them at the other pole until the outside is completely reduced, then
bring them back to the first place.
«Processes by Sulphuration.»—Oxidized Brown Color.—The object is
plunged into some melted sulphur mingled with lampblack, or into a
liquid containing the flowers of sulphur mingled with lampblack. It
is drained and dried. The bronzing obtained resists acids, and may
acquire a beautiful polish which has the appearance of oxidized bronze,
due perhaps to the formation of ferric sulphide, a sort of pyrites
remarkable for its beautiful metallic reflections and its resistance to
chemical agents.
Brilliant Black.—Boil 1 part of sulphur and 10 parts turpentine oil. A
sulphurous oil is obtained of disagreeable odor. Spread this oil with
the brush as lightly as possible, and heat the object in the flame of
an alcohol lamp until the patina takes the tint desired. This process
produces on iron and steel a brilliant black patina, which is extremely
solid.
Blue.—Dissolve 500 drachms of hyposulphite of soda in 1 quart of water,
and 35 grains of lead acetate in 1 quart of water. The two solutions
mingled are heated to the boiling point. The iron is immersed, and
assumes a blue coloration similar to that obtained by annealing.
«Deposit of a Metal or of a Non-Oxidizable Compound.»—Bronze Color.—Rub
the iron smartly with chloride of antimony. A single operation is not
sufficient. It is necessary to repeat it, heating the object slightly.
Black.—I.—Make a paste composed of equal parts of chloride of antimony
and linseed oil. Spread on the object, previously heated, with a brush
or rag; then pass over it a coating of wax and brush it. Finally
varnish with gum lac.
II.—Prepare a solution of bismuth chloride, 10 parts; mercury chloride,
20 parts; cupric chloride, 10 parts; hydrochloric acid, 60 parts;
alcohol, 50 parts; water, 500 parts. Add fuchsine in sufficient
quantity to mask the color.
The mercury chloride is poured into the hydrochloric acid, and the
bismuth chloride and cupric chloride added; then the alcohol. Employ
this mixture with a brush or a rag for smearing the object. The object
may also be immersed in the liquid if it is well cleaned and free from
grease. It is dried and afterwards submitted to boiling water for
half an hour. The operation is repeated until the wished-for tint is
obtained; then the object is passed into the oil bath and taken to the
fire without wiping. The object may also be placed for 10 minutes in
boiling linseed oil.
Brown Tint.—A solution is made of chloride of mercury, 20 parts; cupric
chloride, 10 parts; hydrochloric acid, 60 parts; alcohol, 50 parts;
water, 500 parts. The object is plunged into this solution after being
well cleaned. The solution may also be applied with a brush, giving
two coats. It is afterwards put into hot water. The surface of the
object is covered with a uniform layer of vegetable oil. It is placed
in a furnace at a high temperature, but not sufficient for carbonizing
the oil. The iron is covered with a thin layer of brown oxide, which
adheres strongly to the metal, and which can be beautifully burnished,
producing the appearance of bronze.
Brilliant Black.—The process begins by depositing on the object,
perfectly clean and free from grease, a layer of metallic copper.
For this purpose the following solutions are prepared: (_a_) Cupric
sulphate, 1 part; water, 16 parts. Add ammonia until complete
dissolution. (_b_) Chloride of tin, 1 part; water, 2 parts; and
chlorhydric acid, 2 parts. The object is immersed in solution _b_, and
afterwards in solution _a_. In this way there is deposited on the iron
a very adherent coating of copper. The object, washed with water, is
afterwards rubbed with sulphur, or immersed in a solution of ammonium
sulphhydrate. A dull black coating of cupric sulphide is produced,
which becomes a brilliant black by burnishing.
Blue Black.—The iron object is first heated according to the previous
recipe, but the copper is converted into cupric sulphide, not by a
sulphhydrate, but by a hyposulphite. It is sufficient to dip the
coppered object into a solution of sodium hyposulphite, acidulated with
chlorhydric acid, and raised to the temperature of 175° to 195° F.
Thus a blue-black coating is obtained, unchangeable in air and in
water. After polishing, it has the color of blue steel. It adheres
strongly enough to resist the action of the scratch brush.
Deposition of Molybdenum.—Iron is preserved from rust by covering it
with a coating of molybdenum, as follows: Water, 1,000 parts; ammonium
molybdate, 1 part; ammonium nitrate, 15 to 20 parts. Suspend the object
at the negative pole of a battery. The current ought to have a strength
of 2 to 5 amperes per cubic decimeter.
Deposit of Manganese Peroxide.—The {473} iron or steel is first covered
with a coating of manganese peroxide by immersing as an anode in a bath
containing about 0.05 per cent of chloride or sulphate of manganese and
from 5 to 25 per cent of ammonium nitrate. The bath is electrolyzed
cold, making use of a cathode of charcoal. Feeble currents (1 or 2
amperes) produce an adherent and unchangeable deposit.
Bronzing of Cannon.—Prepare a solution of ferric chloride of density
1.281, 14 parts; mercury chloride, 3 parts; fuming nitric acid, 3
parts; cupric sulphate, 3 parts; water, 80 parts. Give to the piece of
ordnance 2 or 3 coatings of the solution, taking care always to scratch
the preceding layer with a steel brush before spreading the second.
Afterwards, the object is plunged in a solution of potassium sulphide
in 900 parts of water. It is left in this for 10 days. It is removed
by washing with soap and hot water. The object is rinsed, dried, and
finally brushed with linseed-oil varnish.
Green Bronzing.—Dissolve 1 part of acetate of silver in 20 parts of
essence of lavender; coat the surface of iron with this liquid by means
of a brush and raise the temperature to 292° F. A brilliant green color
is developed on the surface.
Coating on Steel Imitating Gilding.—The object is first covered by
the galvanic method by means of a solution of cyanide of copper and
potassium, then covered electrolytically with a thin deposit of zinc.
It is dried and cleaned with a little washed chalk and finally immersed
in boiling linseed oil. The surface of the piece after a few seconds,
at a temperature of 310° F., appears as if there had been a real
penetration of copper and zinc; that is to say, as though there were a
formation of tombac.
Bronzing of Cast Iron.—The piece, when scraped, is coppered with the
following bath: Cupric chloride, 10 parts; hydrochloric acid, 80
parts; nitric acid, 10 parts. It is rubbed with a rag and washed with
pure water, and then rubbed with the following solution: Ammonium
chlorhydrate, 4 parts; oxalic acid, 1 part; water, 30 parts.
Gilding of Iron and Steel.—Chloride of gold is dissolved either in
oil of turpentine or in ether, and this solution is applied with the
brush on the metallic surface, after being perfectly scraped. It is
allowed to dry, and then heated more or less strongly for obtaining the
necessary adherence. When it is dry the gilding is burnished.
«Process by Deposit of a Color or Varnish.»—Beautiful colorations,
resistive to light, may be given to metals by the following method:
The metallic objects are immersed in a colorless varnish with
pyroxyline, and dried in a current of hot air at 176° F. When the
varnish is sufficiently dry, the objects are bathed for a few minutes
in a 2 per cent alcoholic solution of alizarine or of a color of the
same group. By washing with water the yellowish color covering the
object on coming from the coloring bath passes to the golden red.
«Coloring Copper.»—To redden copper hang it from a few minutes to an
hour, according to the shade wanted, in a 5 to 10 per cent solution of
ferrocyanide of potassium in water. By adding a little hydrochloric
acid to the solution the color given to the copper may be made to
assume a purple shade. On removing the copper, dry it in the air or in
fine sawdust, rinse, and polish with a brush or chamois leather, after
drying it again.
«Coloring Brass.»—To redden brass, dip in solution of 5 ounces of
sulphate of copper and 6 to 7 ounces of permanganate of potash in 500
ounces of water.
To blue copper or brass any one of the following recipes may be used: