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.

To blue copper or brass any one of the following recipes may be used:

I.—Dip the article in a solution of 2 ounces of liver of sulphur and 2 ounces of chlorate soda in 1,000 ounces of water.

II.—Dip the article in a solution of ferrocyanide of potassium very strongly acidulated with hydrochloric acid.

III.—Stir the article about constantly in a solution of liver of sulphur in 50 times its weight of water.

A thin sheet of polished copper is entered in the bath and connected with the {474} electric conduit. The current precipitates gold on it. In order to loosen it, the gilt copper plate is placed in a solution of ferric chloride, which dissolves the copper and leaves the gold behind. In this manner gold leaf can be hammered out to almost incredible thinness.

Metal Foil.

Tin foil is the most common foil used, being a combination of tin, lead, and copper, sometimes with properties of other metals.

I is a mirror foil; III is a tin foil.

Tin Foils for Capsules.—

Tin Foils for Wrapping Cheese, etc.—

Tin Foils, for Fine Wrapping, I and II; for Tea Boxes, III.—

Imitation Gold Foils.—

Imitation Silver Foil.—Alloy of tin and zinc: harder than tin and softer than zinc: Zinc, 1 part; tin, 11 parts.

To Attach Gold Leaf Permanently.—Dissolve finely cut isinglass in a little water, with moderate heat, which must not be increased to a boil, and add as much nitric acid as has been used of the isinglass. The adhesive will not penetrate the cardboard or paper.

METH: See Mead.

METHEGLIN: See Mead.

METHYL SALICYLATE, TO DISTINGUISH FROM OIL OF WINTERGREEN: See Wintergreen.

METOL DEVELOPER: See Photography.

METRIC WEIGHTS: See Weights and Measures.

MICE POISON: See Rat Poison.

MICROPHOTOGRAPHS: See Photography.

MILK:

See also Foods.

After allowing the milk to stand 8 hours, remove the top 8 ounces from a quart jar of 4 per cent fat milk by means of a dipper, and count this as 12 per cent fat cream. Count the lowest 8 ounces of the quart fat-free milk. From these the following formula may be obtained, covering fairly well the different percentages required for the different periods of life.

II.—Fresh milk in bottles has been treated with oxygen and carbonic acid under pressure of some atmospheres. By this method it is said to be possible to preserve milk fresh 50 to 60 days. The construction of the bottle is siphon-like.

MILK AS A SUBSTITUTE FOR CELLULOID, BONE, AND IVORY: See Casein.

MILK, CUCUMBER: See Cosmetics.

MILK OF SOAP: See Cleaning Preparations and Methods, under Miscellaneous Methods.

MINARGENT: See Alloys. {476}

MINERAL WATERS: See Waters.

MINOFOR METAL: See Alloys.

MINT CORDIAL: See Wines and Liquors.

MIRRORS

(See also Glass.)

I.—A sheet of pure tin foil, slightly larger than the glass plate to be silvered, is spread evenly on a perfectly plane stone table having a raised edge, and is well cleaned from all dust and impurity. The foil must be free from the slightest flaw or crack. The tin is next covered uniformly to a depth of ¹/₈ of an inch with mercury, preference being given by some to that containing a small proportion of tin from a previous operation. The glass plate, freed from all dust or grease, and repolished if necessary, is then carefully slid over the mercury. This part of the work requires skill and experience to exclude all air bubbles, and even the best workmen are not successful every time. If there is a single bubble or scratch the operation must be repeated and the tin foil is lost; not a small expense for large sizes. When this step has been satisfactorily accomplished the remainder is easy. The glass plate is loaded with heavy weights to press out the excess of mercury which is collected and is used again. After 24 hours the mirror is lifted from the table and placed on edge against a wall, where it is left to drain well.

II.—Solution No. 1 is composed as follows: To 8 ounces of distilled water, brought to a boil, add 12 grains of silver nitrate and 12 grains of Rochelle salts. Let it come to a boil for 6 to 7 minutes; then cool and filter.

Solution No. 2 is made as follows: Take 8 ounces of distilled water, and into a small quantity poured into a tumbler put 19 grains of silver nitrate. Stir well until dissolved. Then add several drops of 26° ammonia until the solution becomes clear. Add 16 grains more of nitrate of silver, stirring well until dissolved. Add balance of distilled water and filter. The filtering must be done through a glass funnel, in which the filter paper is placed. The solution must be stirred with a glass rod. Keep the solutions in separate bottles marked No. 1 and No. 2.

Directions for Silvering: Clean the glass with ammonia and wipe with a wet chamois. Then take half and half of the two solutions in a graduating glass, stirring well with a glass rod. Pour the contents on the middle of the glass to be silvered. It will spread over the surface of itself if the glass is laid flat. Leave it until the solution precipitates.

I.—Take ¹/₃ ounce of clean lead, and melt it with an equal weight of pure tin; then immediately add ¹/₂ ounce of bismuth, and carefully skim off the dross; remove the alloy from the fire, and before it grows cold add 5 ounces of mercury, and stir the whole well together; then put the fluid amalgam into a clean glass, and it is fit for use. When this amalgam is used for silvering, it should be first strained through a linen rag; then gently pour some ounces of it into the globe intended to be silvered; the alloy should be poured into the globe by means of a paper or glass funnel reaching almost to the bottom of the globe, to prevent it splashing the sides; the globe should be turned every way very slowly, to fasten the silvering.

II.—Make an alloy of 3 ounces of lead, 2 ounces of tin, and 5 ounces of bismuth. Put a portion of this alloy into the globe and expose it to a gentle heat until the compound is melted; it melts at 197° F.; then by turning the globe slowly round, an equal coating may be laid on, which, when cold, hardens and firmly adheres.

I.—Place the old mirror in a weak solution of nitric acid—say 5 per cent—which immediately removes the silver. Rinse it a little, and then clean very thoroughly with a pledget of cotton-wool and a mixture of whiting and ammonia. Rouge will answer in place of whiting, or, as a last extreme, finest levigated pumice, first applied to a waste glass to crush down any possible grit. This cleaning is of the utmost importance, as upon its thoroughness depends eventual success. Front, back, and edges must alike be left in a state above suspicion. The {477} plate is then again flowed with weak acid, rinsed under the tap, then flowed back and front with distilled water, and kept immersed in a glass-covered dish of distilled water until the solutions are ready.

The depositing vessel is the next consideration, and it should be realized that unless most of the silver in the solution finds its way on to the face of the mirror it were cheaper that the glass should be sent to the professional mirror-maker. The best plan is to use a glass dish allowing a ¹/₁₆ inch margin all round the mirror, inside. But such a glass dish is expensive, having to be made specially, there being no regular sizes near enough to 4 x 7 or 8 x 5 (usual mirror sizes). If too large, a dish must perforce be used, the sides or ends of which should be filled up with sealing wax. Four strips of glass are temporarily bound together with 2 or 3 turns of string, so as to form a hollow square. The side pieces are ¹/₈ inch longer outside, and the end pieces ¹/₈ inch wider than the mirror glass. This frame is placed in about the center of the dish, moistened with glycerine, and the molten wax flowed outside of it to a depth of about ³/₄ of an inch or more. For economy’s sake, good “parcel wax” may be used, but best red sealing wax is safer. This wax frame may be used repeatedly, being cleaned prior to each silvering operation. It is the only special appliance necessary, and half an hour is a liberal time allowance for making it.

Use a stock solution of silver nitrate of the strength of 25 grains to 1 ounce of distilled water: Take 2 drachms of silver nitrate stock solution and convert it to ammonia nitrate, by adding ammonia drop by drop until the precipitate is redissolved. Add 3 ¹/₂ ounces of distilled water.

In another measure take 80 drops (approximately 74 minims) of 40 per cent formalin. Pour the solution of ammonio nitrate of silver into the measure containing the formalin, then back into the original measure, and finally into the dish containing the glass to be silvered. This should be done rapidly, and the dish containing the mirror well rocked until the silvering is complete, which may be ascertained by the precipitation of a black, flocculent deposit, and the clearing of the solution. The actual process of silvering takes about 2 minutes.

Cleanliness throughout is of the greatest importance. The vessels in which the solutions are mixed should be well rinsed with a solution of bichromate of potash and sulphuric acid, then washed out three or four times under the tap, and finally with distilled water. For cleansing, dip the glass for a short time in a solution of bichromate of potash, to which a little sulphuric acid is added. The glass is afterwards well rinsed for a minute or two under the tap, flooded with distilled water, and dried with a clean linen cloth. A little absolute alcohol is then rubbed on with a soft linen handkerchief, which is immediately rolled into a pad and used for well polishing the surface. The cleaning with alcohol is repeated to avoid risk of failure.

After the mirror has been silvered, hold it under the tap and allow water to flow over it for about 3 minutes. Rinse it with distilled water, and stand it up on edge on blotting paper. When it is quite dry take a pad of very soft wash-leather, spread a small quantity of finest opticians’ rouge on a sheet of clean glass, and well coat the pad with rouge by polishing the sheet of glass. A minute quantity of rouge is sufficient. Afterwards polish the mirror by gently rubbing the surface with the pad, using a circular stroke.

It will be seen that with this process it is unnecessary to suspend the mirror in the silvering solution, as usually recommended. The mirror is laid in the dish, which is a distinct advantage, as the progress of the silvering may be watched until complete. The film also is much more robust than that obtained by the older methods.

II.—Clean the bare portion of the glass by rubbing it gently with fine cotton, taking care to remove any trace of dust and grease. If this cleaning be not done very carefully, defects will appear around the place repaired. With the point of a penknife cut upon the back of another looking glass around a portion of the silvering of the required form, but a little larger. Upon it place a small drop of mercury; a drop the size of a pin’s head will be sufficient for a surface equal to the size of the nail. The mercury spreads immediately, penetrates the amalgam to where it was cut off with the knife, and the required piece may be now lifted and removed to the place to be repaired. This is the most difficult part of the operation. Then press lightly the renewed portion with cotton; it hardens almost immediately, and the glass presents the same appearance.

The cast disk of bronze should be turned up level on both sides, and the edges should be turned or shaped up, the metal being about half an inch thick. On the side which was at the bottom in casting, a line should be drawn to allow for working up the border or frame of the mirror, and on the rest of the smooth surface the design should be drawn, not having too much detail. It is best to mark the lines with a sharp scriber, to prevent their effacement during working. When the disk is marked out, it should be laid on a smoothly planed iron block, and the lines punched to a depth of about ¹/₄ inch, a punch with round edges being used. Then the disk should be turned down to just below the surface of the punched-in metal, and the border or edge formed, finishing smoothly, but without burnishing. The back can be turned down and, with the outer edge, burnished; but the inside of the edge and the face of the mirror should be polished with fine abrasive powder, and finished with fine rouge. When dry, the mirror will appear equally bright all over; but when breathed on the design will show, again disappearing as the moisture is removed. The metal punched in will be more dense than the rest of the surface, and will also be very slightly raised, this being imperceptible unless the polishing has been too long continued.

With iron mirrors a good mottled iron must be used, selecting hematite for preference; but in any case it must be chillable metal. Preferably it should be melted in a crucible, as this causes the least change in the metallic content, and as the metal can be made hot and fluid, it works well. The design must be worked out in iron of about ¹/₈ inch in thickness, and must be level, as it has to touch the molten metal in the bottom of the mold. If preferred, the design may be cast and ground flat, but this depends largely on the design. The chill pattern should be coated with plumbago, and in molding the disk pattern of about ¹/₄ inch in thickness should be laid on a board, and on this the design—chill—should be placed, and the mold should be rammed up from the back in the ordinary manner. The casting should be allowed to get cold in the mold, and should then be removed and dressed in the usual way. It should then be ground bright all over on emery wheels of successively finer grades, and the mirror surface should be buffed and polished until a steely mirror surface is produced. With a good mottled iron the chilled design will not show until the surface is breathed on or rubbed with a greasy rag, but will then show clearly.

MIRROR ALLOYS: See Alloys.

MIRRORS, FROSTED: See Glass.

MIRROR-LETTERING: See Lettering.

MIRROR POLISHES: See Polishes.

MIRRORS, TO CLEAN: See Cleaning Preparations and Methods.

MIRRORS, TO PREVENT DIMMING OF: See Glass.

MIRROR VARNISH: See Varnishes.

MITE KILLER: See Insecticides.

MIXING STICKS FOR PAINT: See Paint.

MODELING WAX: See Wax, Modeling.

MOISTURE: See Insulation.

MOLDS:

See also Casting and Matrix.

MOLDS OF PLASTER: See Plaster.

MOLES:

See also Warts.

Lunar caustic is frequently used to remove warts and moles. It should be wrapped in tin foil or placed in a quill so that it will not touch the bare flesh. Moisten the raised surface and touch with the caustic night and morning. Successive layers of skin will dry up and peel off. When on a level with the surrounding flesh apply a healing ointment. Let the last crust formed drop without touching it. Unless carefully done this process may leave a white scar.

A simple remedy for warts consists in wetting and rubbing them several times a day in a strong solution of common washing soda. The electric treatment, however, is now the most popular.

MORDANTS:

See also Dyes.

MORTAR, ASBESTOS.

Asbestos mortar consists of a mixture of asbestos with 10 per cent of white lime. Canadian asbestos is generally used, which is composed of 80 per cent of asbestos and 20 per cent of serpentine. The asbestos is ground and the coarse powder used for the first rough cast, while the finer material is employed for the second top-plastering. This mortar is highly fire-resisting and waterproof, is only half as heavy as cement mortar, and tough enough to admit of nails being driven in without breaking it.

MOSQUITO REMEDIES: See Insecticides.

MOSS REMOVERS: See Cleaning Preparations and Methods, under Miscellaneous Methods.

MOTHS: See Turpentine.

MOTH PAPER: See Paper.

MOTH TRAPS AND MOTH KILLERS: See Household Formulas.

MOTHER-OF-PEARL: See Pearl.

MOTORS, ANTI-FREEZING SOLUTION FOR: See Freezing Preventives.

MOUNTANTS:

See also Adhesives and Photography.

MOUTH ANTISEPTICS: See Antiseptics.

MOUTH WASHES: See Dentifrices.

MOVING OBJECTS AND HOW TO PHOTOGRAPH THEM: See Photography.

MUCILAGE: See Adhesives.

MUSIC BOXES.

Care must be exercised in taking apart, for if the box is wound up and the fly is removed, the cylinder is ruined. The spring relaxes at a bound, causing the cylinder to turn with such rapidity that the pins cannot resist the teeth, whose force is intensified by the velocity of the cylinder. The pins originally bent forward are broken, or pressed backwards; as they are hardened, they cannot be bent forward again without breaking. This accident involves the cost of a new cylinder, the most expensive part of the apparatus. Besides, the comb almost always loses some teeth and the wheel-work also suffers in its turn.

To avoid such mishaps the careful operator will take the parts asunder in the following order:

1. Remove the comb.

2. Take the apparatus from the box and completely disarm the spring.

3. Remove the barrel.

4. Remove the escapement.

5. Remove the cylinder.

The barrel and the wheels are cleaned like those of a watch.

The cylinder should be handled carefully. The holes should be well cleaned. Oil should be put only on the pivots, especially none on the part of the arbor to which the cylinder is attached. It is the first piece to be replaced, care being taken to see that the arbor turns freely, but without play, between the bridges. When it is in position, put in the escapement, then the barrel, and finally the comb.

The comb, representing the musical part of a simple box, cannot receive too much care. Before replacing it examine the springs closely, and in supplying the ones that are lacking, take for the model of size and form those resembling them the most. If the parts have been put together properly, then, as soon as the comb is screwed in its place, these should be found in good working order: the levée (lift)—that is, that the pins do not lift the teeth too much or too little; the tombée (fall)—that is, that the chords, the bass, the medium, and the treble, fall together; and the visée (pointing)—that the pins catch at the center of the ends of the teeth.

MUSLIN, PAINTING ON: See Painting.

MUSTACHE FIXING FLUID.

Dissolve the balsam in the liquids. Apply a few drops to the mustache with a brush, then twist into the desired shape.

MUSTARD PAPER.

Dissolve the India rubber in the benzol, then stir in the mustard until the mixture is of a suitable consistence for spreading. It was further recommended to remove the fixed oil from the mustard by percolation with benzol. Mustard paper thus made is of good quality, very active, and keeps well. {481}

Mix to a smooth mass, and spread the same over one side of a suitable paper by means of a plaster-spreading machine, or passing the paper over the mass contained in a suitable shallow vessel. Expose to warm air for a short time to dry. Preserve the dry paper in well-closed boxes. It may be useful to know that mustard paper, after spreading, should not be long exposed to light and air. By so doing not only does the mustard bleach but the rubber soon perishes. Moreover, mustard paper is hygroscopic, so that in a moist atmosphere it soon loses its virtue. It is, therefore, highly important that mustard paper should be rapidly dried in a warm atmosphere with free ventilation, then at once stored in well-closed packets. Thus prepared they keep well and remain active for many years.

MUSTARDS: See Condiments.

MYRRH ASTRINGENT: See Dentifrices.

NAIL, INGROWING.

Copious applications of dried powdered alum are sufficient to cure every case of ingrowing nail in about 5 days. The applications are not painful in the least, and the destruction of the pathologic tissue results in the formation of a hard, resistant, and non-sensitive bed for the nail, a perfect cure for the ingrowing tendency. Apply a fomentation of soap and water for 24 hours beforehand and then pour the alum into the space between the nail and its bed, tamponing with cotton to keep the alum in place, and repeating the application daily. The suppuration rapidly dries up, and pain and discomfort are relieved almost at once.

NAIL POLISHES: See Cosmetics.

NAPOLEON CORDIAL: See Wines and Liquors.

NAPHTHOL SOAP: See Soap.

NEATSFOOT OIL.

Place in a clearing flask, agitate vigorously and allow to stand for 8 days in a warm room with daily repetition of the shaking. Then draw off the spirit of wine on top, rinse again with 1,000 parts of spirit of wine (90 per cent) and place the oil in a temperature of about 53 ¹/₂° F. Allow to stand in this temperature for at least 6 weeks, protected from the light, and then filter.

NEEDLES, ANTI-RUST PAPER FOR: See Rust Preventives.

NEGATIVES, HOW TO USE SPOILED: See Photography.

NERVE PASTE: See also Dental Cements, under Cements.