Chapter I: II III IV V VI VII (1)

Platinum 62.75 62.75 62.75 54.32 0.5 0.5 — Copper 18 16.20 16.20 16 18.5 18.5 25 Nickel 18 18 16.50 24.70 — 2 1 Cadmium 1.25 1.25 1.25 1.25 — — — Cobalt — — 1.50 1.96 — — — Tungsten — 1.80 1.80 1.77 — — — Palladium — — — — 72 72 70 Silver — — — — 6.5 7 4 Rhodium — — — — 1 — — Gold — — — — 1.5 — —

A non-magnetic alloy for watch-springs, wheels, etc.: Gold, 30 to 40 parts; palladium, 30 to 40 parts; copper, 10 to 20 parts; silver, 0.1 to 5 per cent; cobalt, 0.1 to 2.5 per cent; tungsten, 0.1 to 5 per cent; rhodium, 0.1 to 5 per cent; platinum, 0.1 to 5 per cent.

«An Alloy for Watch Pinion Sockets.»—Gold, 31 parts; silver, 19 parts; copper, 39 parts; palladium, 1 part.

«Replacing Rubies whose Settings have Deteriorated.»—Enlarge, with the squarer (steel brooch for enlarging holes), the hole of the old setting, and adjust it, with hard rubbing, to the extremity of a stem of pierced brass wire. Take the stem in an American nippers, and set the ruby at the extremity (the setting may be driven back by using a flat burnishing tool, very gently). Then take off with a cleaving file the part of the stem where the ruby is set, and diminish it to the thickness desired, by filing on the finger, or on cork. These operations finished, {737} a set stopper is obtained which now needs only to be solidly fixed at the suitable height, in the hole prepared.

«To Straighten Bent Teeth.»—Bent teeth are straightened by means of the screwdriver used as a lever against the root of the adjacent teeth, and bent pivots may be held in the jaws of the pliers and the pinion bent with the fingers in the direction and to the extent required. For such a purpose, pliers having the jaws lined with brass are used so that the pivot is not bruised, and the bending has to be done with great care.

«To Renew a Broken Barrel Tooth.»—Frequently, in consequence of the breaking of a spring, a tooth of a barrel is broken. Sometimes it may only be bent, in which case the blade of a penknife may be used with care. If 2 or 3 successive teeth are lacking, the best way is to change the barrel, but a single tooth may be easily renewed in this way: Drill a hole through the thickness of the tooth, taking care not to penetrate the drum; then fit in a piece of metal tightly and give it, as well as possible, the correct form of the tooth. To assure solidity, solder it; then clean and round the edges. Properly executed the repair will scarcely be noticed.

«Heated Sawdust.»—Sawdust is known to have been employed from time immemorial by watchmakers and goldsmiths for the purpose of drying rinsed articles. The process of drying can be accelerated four-fold if the sawdust is heated before use. This must, however, be done with great caution and constant stirring.

«To Repair a Dial, etc., with Enamel Applied Cold.»—There are two kinds of false enamel for application, when cold, to damaged dials. The first, a mixture of white rosin and white lead, melts like sealing wax, which it closely resembles. It is advisable when about to apply it to gently heat the dial and the blade of a knife, and with the knife cut the piece of enamel of the requisite size and lay it on the dial. The new enamel must project somewhat above the old. When cold the surface is leveled by scraping, and a shining surface is at once produced by holding at a little distance from the flame of a spirit lamp. It is necessary to be very careful in conducting this operation, as the least excess of heat will burn the enamel and turn it yellow. It is, however, preferable to the following although more difficult to apply, as it is harder and does not become dirty so soon. The second false enamel contains white lead mixed with melted white wax. It is applied like cement, neatly filling up the space and afterwards rubbing with tissue paper to produce a shining surface. If rubbed with a knife blade or other steel implement its surface will be discolored.

«Lettering a Clock Dial.»—Painting Roman characters on a clock dial is not such a difficult task as might at first be imagined. If one has a set of drawing instruments and properly proportions the letters, it is really simple. The letters should be proportioned as follows: The breadth of an “I” and a space should equal 1/2 the breadth of an “X,” that is, if the “X” is 1/2 inch broad, the “I” will be 3/16 inch broad and the space between letters inch, thus making the “I” plus one space equal to 1/4 inch or half the breadth of an “X.” The “V’s” should be the same breadth as the “X’s.” After the letters have been laid off in pencil, outline them with a ruling pen and fill in with a small camel’s-hair brush, using gloss black paint thinned to the proper consistency to work well in the ruling pen. Using the ruling pen to outline the letters gives sharp straight edges, which it would be impossible to obtain with a brush in the hands of an inexperienced person.

«Verification of the Depthings.»—In the verge watches, the English watches, and those of analogous caliber, it is often difficult to verify the depthings, except by the touch. For this reason we often find the upper plate pierced over each depth. In the jeweled places, instead of perforating the upper plate, it suffices to deposit a drop of very limpid oil on the ruby, taking care that it does not scatter. In this manner a lens is formed and one may readily distinguish the depthing.

«To Make or Enlarge a Dial Hole.»—By wetting the graver or the file with spirit of turpentine, cracks may be avoided and the work will be accomplished much quicker.

«To Repair a Repeating Clock-Bell.»—When the bell is broken, whether short off or at a distance, file it away and pierce it, and after having sharpened a little the stem of the spring which remains, push by force, in the hole just made, a thin piece of solder (pewter). The sound will not have changed in any appreciable manner.

A seconds pendulum of a regulator, which has no compensation for temperature will cause the clock to lose about {738} 1 second per day for each 3 degrees of increase in heat. A watch without a compensation balance will lose 6.11 seconds in 24 hours for each increase of 1° F. in heat.

«To Remedy Worn Pinions.»—Turn the leaves or rollers so that the worn places upon them will be toward the arbor or shaft and fasten them in that position. If they are “rolling pinions,” and they cannot be secured otherwise, a little soft solder should be used.

«Watchmakers’ Oil.»—I.—Put some lead shavings into neat’s foot oil, and allow to stand for some time, the longer the better. The lead neutralizes the acid, and the result is an oil that never corrodes or thickens.

II.—Stir up for some time best olive oil with water kept at the boiling point; then after the two fluids have separated, decant the oil and shake up with a little freshly burned lime. Let the mixture stand for some weeks in a bottle exposed to the sunlight and air, but protected from wet and dirt. When filtered, the oil will be nearly colorless, perfectly limpid, and will never thicken or become rancid.

«To Weaken a Balance Spring.»—A balance spring may need weakening; this is effected by grinding the spring thinner. Remove the spring from the collet and place it upon a piece of pegwood cut to fit the center cod. A piece of soft iron wire, flattened so as to pass freely between the coils and charged with a little powdered oilstone, will serve as a grinder, and with it the strength of the spring may soon be reduced. Operations will be confined to the center coil, for no other part of the spring will rest sufficiently against the wood to enable it to be ground, but this will generally suffice. The effect will be rather rapid; therefore care should be taken or the spring may be made too weak.

«To Make a Clock Strike Correctly.»—Pry the plates apart on the striking side, slip the pivots of the upper wheels out, and having disconnected them from the train, turn them partly around and put them back. If still incorrect, repeat the experiment. A few efforts at most will get them to work properly. The sound in cuckoo clocks is caused by a wire acting on a small bellows which is connected with two small pipes like organ pipes.

«To Reblack Clock Hands.»—One coat of asphaltum varnish will make old rusty hands look as good as new, and will dry in a few minutes.

«To Tighten a Ruby Pin.»—Set the ruby pin in asphaltum varnish. It will become hard in a few minutes and be much firmer and better than the gum shellac, generally used.

«To Loosen a Rusty Screw in a Watch Movement.»—Put a little oil around the screw; heat the head lightly by means of a red-hot iron rod, applying the same for 2 or 3 minutes. The rusty screw may then be removed as easily as though it had just been put in.

«Gilding Watch Movements.» (See also Gilding.)—In gilding watch movements, the greatest care must be observed with regard to cleanliness. The work is first to be placed into a weak solution of caustic potash for a few minutes, and then rinsed in cold water. The movements are now to be dipped into pickling acid (nitrous acid) for an instant, and then plunged immediately into cold water. After being finally rinsed in hot water, they may be placed in the gilding bath and allowed to remain therein until they have received the required coating. A few seconds will generally be sufficient, as this class of work does not require to be very strongly gilt. When gilt, the movements are to be rinsed in warm water, and scratch-brushed; they may then be returned to the bath, for an instant, to give them a good color. Lastly, rinse in hot water and place the movements in clean box sawdust. An economical mode of gilding watch movements is to employ a copper anode—working from the solution, add 10 parts of cream of tartar and a corresponding quantity of elutriated chalk to obtain a pulp that can be put on with the brush. The gilding or silvering obtained in this manner is pretty, but of slight durability. At the present time this method is only seldom employed, since the electroplating affords a means of producing gilding and silvering in a handsome and comparatively cheap manner, the metallic coating having to be but very thin. Gold and silver for this kind of work are used in the form of potassium cyanide of gold or potassium cyanide of silver solutions, it being a custom to copper the zinc articles previously by the aid of a battery, since the appearance will then be much handsomer than on zinc alone. Gilding or silvering with leaf metal is done by polishing the surface of the zinc bright and coating it with a very tough linseed-oil varnish diluted with 10 times the quantity of benzol. The metallic leaf is then laid on and polished with an agate. {739}

WATCHMAKERS’ CLEANING PREPARATIONS: See Cleaning Preparations and Methods.

WATCH MOVEMENTS, PALLADIUM PLATING OF: See Plating.

«Water, Natural and Artificial»

In making an artificial mineral water it must be remembered that it is seldom possible to reproduce the water by merely combining its chemical components. In other words, the analysis of the water cannot serve as a basis from which to prepare it, because even though all of the components were put together, many would be found insoluble, and others would form new chemical combinations, so that the result would differ widely from the mineral water imitated.

For example, carbonate of magnesia and carbonate of lime, which are important ingredients in most mineral waters, will not make a clear solution unless freshly precipitated. Hence, when these are to be reproduced in a mineral water it is customary to employ other substances, which will dissolve at once, and which will, upon combining, produce these salts. The order in which the salts are added is also a very important matter, for by dissolving the salts separately and then carefully combining them, solutions may be effected which would be impossible were all the salts added together to the water in the portable fountain.

In this connection the following table will be found useful:

Group I

Ammonium carbonate. Ammonium chloride. Sodium borate (borax). Potassium carbonate. Potassium chloride. Potassium nitrate. Potassium sulphate. Sodium bromide. Sodium carbonate. Sodium chloride. Sodium fluoride. Sodium iodide. Sodium nitrate. Sodium phosphate. Sodium pyrophosphate. Sodium silicate. Sodium sulphate.

Group 2

Lithium carbonate.

Group 3

Aluminum chloride. Barium chloride. Calcium bromide. Calcium chloride. Calcium nitrate. Magnesium nitrate. Strontium chloride. Lithium chloride.

Group 4

Magnesium sulphate. Alum (potassa or soda alum).

Group 5

Lime carbonate. Magnesium carbonate hydrate. Lime sulphate precipitate.

Group 6

Lithium carbonate. Acid hydrochloric. Acid sulphuric. Iron chloride. Iron pyrophosphate. Iron sulphate. Manganese chloride. Manganese sulphate.

Group 7

Sodium arseniate, or sodium sulphide, or acid hydrosulphuric.

Explanation of Groups.—The explanation of the use of these groups is simple. When about to prepare an artificial mineral water, first ascertain from the formula which of the ingredients belong to group 1. These should be dissolved in water, and then be filtered and added to distilled water, and thoroughly agitated. Next the substance or substances belonging to group 2 should be dissolved in water, then filtered and added to the water, which should again be agitated. And so the operation should proceed; whatever ingredients are required from each group should be taken in turn, a solution made, and this solution, after being filtered, should be separately added to the fountain, and the latter be well agitated before the following solution is added.

For groups 1, 3, and 4, the salts should be dissolved in 5 times their weight of boiling, or 10 times their weight of cold, water. For group 2 (lithium carbonate) the proportions should be 1 part of lithium carbonate to about 130 parts of cold or boiling water. The substances mentioned in group 5 are added to the portable fountain in their solid state, and dissolve best when freshly precipitated. As carbonic acid gas aids their solution, it is best to charge the fountain after they are added, and agitate thoroughly, blowing off the charge afterwards if necessary.

In group 5 the lithium carbonate is dissolved in the acids (see also group 2), the iron and manganese salts are dissolved in 5 parts of boiling, or 10 parts of cold, water, the solution quickly filtered, the acids added to it, and the whole mixture added to the fountain already charged with gas, the cap being quickly taken off, and the solution poured in. The iron and manganese salts easily oxidize and produce turbidity, therefore the atmospheric air should be carefully {740} blown off under high pressure several times while charging fountains. The substances mentioned in group 7 are never put into the fountain, except the arseniate of sodium in the case of Vichy water, which contains but a trifling amount of this compound.

Most of the solutions may be prepared beforehand and be used when required, thus saving considerable time.

Formulas for various waters will be given at the end of this article.

A question which arises in preparing mineral waters is: What is the best charging pressure? As a general rule, they are charged to a lower pressure than plain soda; good authorities even recommend charging certain mineral waters as low as 30 pounds pressure to the square inch, but this seems much too low a pressure for the dispensing counter. From 50 to 120 pounds pressure would be a good limit, while plain soda may be served out as high as 180 pounds. There must be enough pressure completely to empty the fountain, while enabling sufficient gas to be retained by the water to give it a thorough pungency. Moreover, a high pressure to the mineral water enables a druggist at a pinch, when he runs out of plain soda, to use his Vichy water, instead, with the syruped drinks. The taste of the Vichy is not very perceptible when covered by the syrup, and most customers will not notice it.

«Apollinaris Water.»—

Sodium carbonate 2,835 grains Sodium sulphate 335 grains Sodium silicate 10 grains Magnesium chloride 198 grains Calcium chloride 40 grains Potassa alum 57 grains Magnesium carbonate hydrate 158 grains Iron sulphate 21 grains

«Hunyadi Water.»—

Magnesium sulphate 400 parts Sodium sulphate 400 parts Potassium sulphate 2 parts Sodium chloride 31 parts Sodium bicarbonate 12 parts Water 1 quart

«Lithia Water.»—

Lithium carbonate 120 grains Sodium bicarbonate 1,100 grains Carbonated water 10 gallons

For “still” lithia water, substitute lithium citrate for the carbonate in the above formula.

«Seltzer Water.»—Hydrochloric acid (chemically pure), 2,520 grains; pure water, 40 ounces. Mix and add marble dust, 240 grains; carbonate of magnesium, 420 grains. Dissolve, and after 1 hour add bicarbonate of sodium, 2,540 grains. Dissolve, then add sufficient pure water to make 10 gallons. Filter and charge to 100 pounds pressure.

«Vichy Water.»—The following formula, based on the analysis of Bauer-Struve, yields an imitation of

_Vichy_ (_Grande Grille_).

Sodium iodide 0.016 parts Sodium bromide 0.08 parts Sodium phosphate 2 parts Sodium silicate 80 parts Potassium sulphate 125 parts Sodium chloride 139 parts Sodium carbonate 6,792 parts Aluminum chloride 1 part Strontium chloride 1 part Ammonium chloride 3 parts Magnesium chloride 24 parts Calcium chloride 170 parts Manganese sulphate 0.46 parts Iron sulphate 1 part Sulphuric acid 40 parts Water to make 10 gallons

Mix the first 7 ingredients with about 10 times their weight of water and filter. In the same manner, mix the next 5 ingredients with water and filter; and then the last 3 ingredients. Pour these solutions into sufficient water contained in a fountain to make 10 gallons, and charge at once with carbon dioxide gas.

Waters like the above are more correctly named “imitation” than “artificial,” as the acidic and basic radicals may bear different relations to one another in the natural and the other.

«PURIFYING WATER.»

See also Filters.

If an emulsion of clay is poured into a soap solution, the clay gradually separates out without clarifying the liquid. When a few drops of hydrochloric acid, however, are added to a soap solution and a small quantity—about 1.5 per cent—of a clay emulsion poured in, the liquid clarifies at once, with formation of a plentiful sediment. Exactly the same process takes place when the waste waters from the combing process in spinning are treated with clay. The waters which remain turbid for several days contain 500 to 800 grams of fatty substances per cubic meter. If to 1 liter of this liquid 1 gram of clay is added, with 15 to 20 per cent of water, the liquid clarifies with separation of a sediment and assumes a golden-brown {741} color. Besides the fatty substances, this deposit also contains a certain quantity of nitrogenous bodies. Dried at (100° C.) 212° F., it weighs about 1.6 grams and contains 30 per cent of fat. The grease obtained from it is clear, of good quality, and deliquesces at 95° F. After removal of this fat, the mass still contains 1.19 per cent of nitrogen.

«Sterilization of Water with Lime Chloride.»—In order to disinfect and sterilize 1,000 parts of drinking water, 0.15 parts of dry chloride of lime are sufficient. The lime is stirred with a little water into a thin paste and introduced, with stirring, into the water to be disinfected and a few drops of officinal hydrochloric acid are added. After 1/2 hour the clarification and disinfection is accomplished, whereupon 0.3 parts of calcium sulphite are added, in order to kill the unpleasant smell and taste of the chlorine.

«Clarifying Muddy Water.»—The water supply from rivers is so muddy at times that it will not go through the filter. When this happens agitate each barrel of water with 2 pounds of phosphate of lime and allow it to settle. This will take but a few minutes, and it will be found that most of the impurities have been carried down to the bottom. The water can then be drawn off carefully and filtered.

«Removal of Iron from Drinking Water.»—The simplest method for removing the taste of iron in spring water is to pass the water through a filter containing a layer of tricalcic phosphate either in connection with other filtering materials or alone. The phosphate is first recovered in a gelatinous form, then dried and powdered.

«For Hardness.»—A solution perfectly adapted to this purpose, and one which may be kept a long time, is prepared as follows:

Thirty-five parts of almond oil are mixed with 50 parts of glycerine of 1.26 specific gravity and 8.5 parts of 50 per cent soda lye, and boiled to saponification. To this mixture, when it has cooled to from 85° to 90° C. (185° to 194° F.), are added 100 to 125 parts of boiling water. After cooling again, 500 parts of water are added, and the solution is poured into a quart flask, with 94 per cent alcohol to make up a quart. After standing 2 months it is filtered. Twenty hydrolimeter degrees of this solution make, with 40 parts of a solution of 0.55 grams of barium chloride in 1 quart of water, a dense lather 1 centimeter high.

WATER (COPPER): See Copper.

WATER ICES: See Ice Creams.

WATER, TO FREEZE: See Refrigeration.

WATER JACKETS, ANTI-FREEZING SOLUTIONS FOR: See Freezing Preventives.

WATER SPOTS, PRIMING FOR: See Paint.

WATER STAINS: See Wood.

WATER-LILY ROOTS: See Pyrotechnics.

WATER, STIRRED YELLOW, SCARLET AND COLORLESS: See Pyrotechnics.

WATERS (TOILET): See Cosmetics.

WATER-GLASS CEMENTS: See Adhesives.

WATER GLASS IN STEREOCHROMATIC PAINTING: See Stereochromy.

«Waterproofing»

(See also Enamels, Glazes, Paints, Preservatives, Varnishes.)

«Waterproofing Brick Arches.»—Waterproofing of brick arches is done in the following manner: The masonry is first smoothed over with cement mortar. This is then covered with a special compound on which a layer of Hydrex felt is laid so as to lap at least 12 inches on the transverse seams. Five layers of compound and 5 of felt are used, and special attention is paid to securing tightness around the drain pipes and at the spandrel walls. In fact the belt is carried up the back of the latter and turned into the joint under the coping about 2 inches, where it is held with cement mortar. The waterproofing on the arches is protected with 1 inch of cement mortar and that on the walls with a single course of brickwork.

«Waterproofing Blue Prints.»—Use refined paraffine, and apply by immersing the print in the melted wax, or more conveniently as follows: Immerse in melted paraffine until saturated, a number of pieces of an absorbent cloth a foot or more square. When withdrawn and cooled they are ready for use at any time. {742} To apply to a blue print, spread one of the saturated cloths on a smooth surface, place the dry print on it with a second waxed cloth on top, and iron with a moderately hot flatiron. The paper immediately absorbs paraffine until saturated, and becomes translucent and highly waterproofed. The lines of the print are intensified by the process, and there is no shrinking or distortion. As the wax is withdrawn from the cloths, more can be added by melting small pieces directly under the iron.

By immersing the print in a bath of melted paraffine the process is hastened, but the ironing is necessary to remove the surplus wax from the surface, unless the paper is to be directly exposed to the weather and not to be handled. The irons can be heated in most offices by gas or over a lamp, and a supply of saturated cloths obviates the necessity of the bath. This process, which was originally applied to blue prints to be carried by the engineer corps in wet mines, is equally applicable to any kind of paper, and is convenient for waterproofing typewritten or other notices to be posted up and exposed to the weather.

«Waterproof Coatings.»—I.—Rosin oil, 50 parts; rosin, 30 parts; white soap, 9 parts. Apply hot on the surfaces to be protected.

II.—It has been observed that when gluten dried at an ordinary temperature, hence capable of absorbing water, is mixed with glycerine and heated, it becomes water-repelling and suitable for a waterproof paint. One part of gluten is mixed with parts of glycerine, whereby a slimy mass is obtained which is applied on fabrics subsequently subjected to a heat of 248° F. The heating should not last until all glycerine has evaporated, otherwise the coating becomes brittle and peels off.

«Waterproofing Canvas.»—I.—The canvas is coated with a mixture of the three solutions named below:

1. Gelatin, 50 parts; by weight, boiled in 3,000 parts of water free from lime. 2. Alum, 100 parts, dissolved in 3,000 parts of water. 3. Soda soap dissolved in 2,000 parts of water.

II.—Prepare a zinc soap by entirely dissolving 56 parts of soft soap in 125 to 150 parts of water. To the boiling liquid add, with constant stirring, 28 to 33 parts of zinc vitriol (white vitriol). The zinc soap floats on top and forms, after cooling, a hard white mass, which is taken out. In order to clean it of admixed carbonic alkali, it must be remelted in boiling fresh water. Next place 232.5 parts of raw linseed oil (free from mucus) in a kettle with 2.5 parts of best potash, and 5 parts of water. This mass is boiled until it has become white and opaque and forms a liquid, soap-like compound. Now, add sugar of lead, 1.25 parts; litharge, 1 part; red lead, 2 parts; and brown rosin, 10.5 parts. The whole is boiled together about 1 hour, the temperature not being allowed to exceed 212° F., and stirring well from time to time. After this add 15 parts of zinc soap and stir the whole until the metal soap has combined with the oil, the temperature not exceeding 212° F. When the mixture is complete, add a solution of caoutchouc, 1.2 parts, and oil of turpentine, 8.56 parts, which must be well incorporated by stirring. The material is first coated on one side by means of a brush with this composition, which must have a temperature of 158° F. Thereupon hang it up to dry, then apply a second layer of composition possessing the same temperature, which is likewise allowed to dry. The fiber is now filled out, so that the canvas is waterproof.

«Waterproofing Corks.»—For the purpose of making corks as impervious as possible, while at the same time keeping them elastic, saturate them with caoutchouc solution. Dissolve caoutchouc in benzine in the ratio of 1 part of caoutchouc to 19 parts of benzine. Into this liquid lay the corks to be impregnated and subject them to a pressure of 150 to 180 pounds by means of a force pump, so that the liquid can thoroughly enter. The corks thus treated must next be exposed to a strong draught of air until all trace of benzine has entirely evaporated and no more smell is noticeable.

«WATERPROOFING FABRICS.»

It will be convenient to divide waterproof fabrics into two classes, viz., those which are _impervious_ to water, and those which are _water-repellent_. It is important to make this distinction, for, although all waterproof material is made for the purpose of resisting water, there is a vast difference between the two classes. The physical difference between them can be briefly summed up as follows: Fabrics which are completely impervious to water comprise oil-skins, mackintoshes, and all materials having a water-resisting film on one or both sides, or in the interior of the fabric. Those coming under the second heading of water-repellent materials do not possess {743} this film, but have their fibers so treated as to offer less attraction to the water than the water molecules have for themselves.

The principal members of the first group are the rubber-proofed goods; in these the agent employed is rubber in greater or less quantity, together with other bodies of varying properties. Before enlarging on this class, it will be necessary to give a short description of the chemical and physical properties of rubber.

Rubber, or caoutchouc, is a natural gum exuding from a large number of plants, those of the _Euphorbiaceæ_ being the chief source for the commercial variety. The raw material appears on the market in the shape of blocks, cakes, or bottle-shaped masses, according to the manner in which it has been collected. It possesses a dark-brown—sometimes nearly black-exterior; the interior of the mass is of a lighter shade, and varies from a dingy brown to a dirty white, the color depending on the different brands and sources. In the raw state its properties are very different from what they are after going through the various manufacturing processes, and it has only a few of the characteristics which are generally associated with India rubber. Chemically it is a complex hydrocarbon with the formula C_〈45〉H_〈36〉, and appears to consist of a highly porous network of cells having several different rosins in their interstices. It is perfectly soluble in no single solvent, but will yield some of its constituents to many different solvents. At a temperature of 10° C. (50° F.) raw caoutchouc is a solid body and possesses very little elasticity. At 36° C. (97° F.) it is soft and elastic to a high degree, and is capable of being stretched 16 times its length. Further increase of temperature lessens its elastic properties, and at 120° C. (248° F.) it melts. While in the raw condition it has several peculiar properties, one of which is: After stretching, and cooling suddenly while stretched, it retains its new form, and only regains its former shape on being warmed. Another striking feature is its strong adhesive capacity; this property is so powerful that the rubber cannot be cut with a knife unless the blade is wet; and freshly cut portions, if pressed together, will adhere and form a homogeneous mass. From these facts it will be seen how it differs from rubber in the shape of a cycle tire or other manufactured form.

The most valuable property possessed by raw caoutchouc is that of entering into chemical combination with sulphur, after which its elasticity is much increased; it will then bear far greater gradations of heat and cold. This chemical treatment of caoutchouc with sulphur is known as “vulcanizing,” and, if properly carried out, will yield either soft vulcanized rubber or the hard variety known as vulcanite. On the other hand, caoutchouc, after vulcanizing, has lost its plastic nature, and can no longer be molded into various shapes, so that in the production of stamped or molded objects, the customary method is to form them in unvulcanized rubber and then to vulcanize them.

Raw caoutchouc contains a number of natural impurities, such as sand, twigs, soil, etc.; these require removing before the manufacturing processes can be carried out. The first operation, after rough washing, is to shred the raw material into small strips, so as to enable the impurities to be washed out. This process is carried out by pressing the rubber against the surface of a revolving drum (_A_, Fig. 1), carrying a number of diagonally arranged knives, _B_, on its surface. A lever, _C_, presses the rubber against the knives; _D_ is the fulcrum on which _C_ works, _E_ being a weight which throws back the lever on the pressure being removed. During {744} this operation a jet of water is kept playing onto the knives to cool and enable them to cut.

Following this comes the passage between a pair of corrugated steel rollers (as shown in Fig. 2). These rollers have each a different speed, so that the rubber gets stretched and squeezed at the same time. Immediately over the rollers a water pipe is fixed, so that a steady stream of water washes out all the sand and other extraneous matter. In Fig. 2, _AA_ are the steel rollers, while _B_ is a screw working springs which regulate the pressure between the rollers. The power is transmitted from below from the pulley, _C_, and thence to the gearing.

The next operation, after well drying, is to thoroughly masticate the shredded rubber between hot steel rollers, which resemble those already described, but usually have a screw-thread cut on their surfaces. Fig. 3 shows the front view of this masticating machine, _A_ being the rollers, while the steam pipe for heating is shown at _B_. Fig. 3_a_ gives a top view of the same machine, showing the two rollers.

After passing several times through these, the rubber will be in the form of homogeneous strips, and is then ready either for molding or dissolving. As we are dealing solely with waterproofed textiles, the next process which concerns us is the dissolving of the rubber in a suitable solvent. Benzol, carbon bisulphide, oil of turpentine, ether, and absolute alcohol, will each dissolve a certain amount of rubber, but no one of them used alone gives a thorough solution. The agent commonly employed is carbon bisulphide, together with 10 per cent of absolute alcohol. Whatever solvent is used, after being steeped in it for some hours the caoutchouc swells out enormously, and then requires the addition of some other solvent to effect a complete solution. A general method is to place the finely shredded rubber in a closed vessel, to cover it with carbon bisulphide, and allow to stand for some hours. Toward the end of the time the vessel is warmed by means of a steam coil or jacket, and 10 parts absolute alcohol are added for every 100 parts of carbon bisulphide. The whole is then kept gently stirred for a few hours. Fig. 4 shows a common type of the vessel used for dissolving rubber. In this diagram _A_ is the interior of the vessel, and _B_ a revolving mixer in the same. The whole vessel is surrounded by a steam jacket, _C_, with a steam inlet at _D_ and a tap for condensed water at _E_. _F_ is the cock by which the solution is drawn off.

After the rubber is dissolved, about 12 to 24 per cent of sulphur is added, and thoroughly incorporated with the solution. The sulphur may be in the form of chloride of sulphur, or as sulphur pure and simple. A very small quantity of sulphur is required to give the necessary result, 2 to 3 per cent being sufficient to effect vulcanization; but a large quantity is always added to hasten the operation.

Even after prolonged treatment with the two solvents, a solution of uniform consistency is never obtained: clots of a thicker nature will be found floating in the solution, and the next operation is to knead it up so as to obtain equal {745} density throughout. Fig. 5 will give an idea of how this mixing is done.

At the top of a closed wooden chamber is a covered reservoir, _A_, containing the solution of rubber. A long slit at the base of this reservoir allows the solution to fall between sets of metal rollers, _BBB_ below. Neighboring rollers are revolving in opposite directions, and at different speeds, so that, after passing all three sets of rollers, and emerging at the bottom, the solution should be of uniform consistency. _CCC_ are the guiding funnels, and _EE_ are scrapers to clear the solution from the rollers. _D_ is a wedge-shaped plug worked by a rack and pinion, and regulates the flow of the solution.

It now remains to apply the rubber to the fabric and vulcanize it. Up to this stage the sulphur has only been mechanically mixed with the rubber; the aid of heat is now required to bring about chemical combination between the two. This process, which is known as “burning,” consists in subjecting the rubber-covered fabric to a temperature of about 248° F. Sulphur itself melts at 239° F., and the temperature at which combination takes place must be above this. Fig. 6 shows one of the methods of spreading the rubber on the cloth. _A_ is the tank containing the solution with an outlet at the bottom arranged so as to regulate the flow of solution. The fabric passes slowly underneath this, receiving as it travels a thin coating of the waterproofing. The two rollers at _B_ press the solution into the fabric and distribute the proofing evenly over the entire surface.

After leaving the two squeezing rollers, the cloth travels slowly through a covered chamber, _C_, having a series of steam pipes, _EE_, underneath, to evaporate the solvent; this condenses on the upper portion of the chamber, which is kept cooled, and flows down the sides into suitable receptacles. After this the proofed cloth is vulcanized by passing round metal cylinders heated to the necessary temperature, or by passing through a heated chamber. Fig. 7 shows the spreading of rubber between two fabrics. The two cloths are wound evenly on the rollers, _BB_; from this they are drawn conjointly through the rollers, _D_, the stream of proofing solution flowing down between the rollers, which then press the two fabrics together with the rubber inside. The lower rollers marked _CC_ are heated to the necessary degree, and cause the rubber and sulphur to combine in chemical union.

So far the operation of proofing has been described as though pure rubber only was used; in practice the rubber forms only a small percentage of the proofing material, its place being taken by cheaper bodies. One of the common ingredients of proofing mixtures is boiled linseed oil, together with a small quantity of litharge; this dries very quickly, and forms a glassy flexible film. Coal tar, shellac, colophony, etc., are all used, together with India-rubber varnish, to make {746} different waterproof compositions. Oil of turpentine and benzol form good solvents for rubber, but it is absolutely essential that both rubber and solvent be perfectly anhydrous before mixing. Oil of turpentine, alcohol, etc., can be best deprived of water by mixing with either sulphuric acid or dehydrated copper sulphate, and allowing to stand. The acid or the copper salt will absorb the water and sink to the bottom, leaving a supernatant layer of dehydrated turpentine or whatever solvent is used. All the sulphur in a rubber-proofed cloth is not in combination with the rubber; it is frequently found that, after a lapse of time, rubber-proofed material shows an efflorescence of sulphur on the surface, due to excess of sulphur, and occasionally the fabric becomes stiff and the proofing scales off. Whenever a large proportion of sulphur is present, there is always the danger of the rubbers forming slowly into the hard vulcanite state, as the substance commonly called vulcanite consists only of ordinary vulcanized rubber carried a stage further by more sulphur being used and extra heat applied. If after vulcanizing, rubber is treated with caustic soda, all this superfluous sulphur can be extracted; if it is then well washed the rubber will retain its elasticity for a long period. With the old methods of proofing, a sheet of vulcanized rubber was cemented to a fabric with rubber varnish, and frequently this desulphurizing was performed before cementing together. The result was a flexible and durable cloth, but of great weight and thickness, and expensive to produce.

The chemistry of rubber is very little understood; as mentioned previously, rubber is a highly complex body, liable to go through many changes. These changes are likely to be greater in rubber varnish, consisting of half a dozen or more ingredients, than in the case of rubber alone. The action of sunlight has a powerful effect on rubber, much to its detriment, and appears to increase its tendency to oxidize. Vulcanized rubber keeps its properties better under water than when exposed to the air, and changes more slowly if kept away from the light. It appears as though a slight decomposition always takes place even with pure rubber; but the presence of so many differently constituted substances as sometimes occur in rubber solutions no doubt makes things worse. Whenever a number of different bodies with varying properties are consolidated together by heat, as in the case of rubber compositions, it is only reasonable to expect there will be some molecular rearrangement going on in the mass; and this can be assigned as the reason why some proofings last as long again as others. Some metallic salts have a very injurious action on rubber, one of the worst being copper sulphate. Dyers are frequently warned that goods for rubber-proofing must be free from this metal, as its action on rubber is very powerful, though but little understood. As is generally known, grease in any form is exceedingly destructive to rubber, and it should never be allowed in contact in the smallest proportion. Some compositions are made up by dissolving rubber in turpentine and coal tar; but in this case some of the rubber’s most valuable properties are destroyed, and it is doubtful if it can be properly vulcanized. Owing to rubber being a bad conductor of heat, it requires considerable care to vulcanize it in any thickness. A high degree of heat applied during a short period would tend to form a layer of hard vulcanite on the surface, while that immediately below would be softer and would gradually merge into raw rubber in the center.

The different brands of rubber vary so much, especially with regard to solubility, that it is always advisable to treat each brand by itself, and not to make a solution of two or more kinds. Oilskins and tarpaulins, etc., are mostly proofed by boiled linseed oil, with or without thickening bodies added. They are not of sufficient interest to enlarge upon in this article, so the second, or “water-repellent,” class has now to be dealt with.

All the shower-proof fabrics come under this heading, as well as every cloth which is pervious to air and repulsive to water. The most time-honored recipe for proofing woollen goods is a mixture of sugar of lead and alum, and dates back hundreds of years. The system of using this is as follows: The two ingredients are dissolved separately, and the solutions mixed together. A mutual decomposition results, the base of the lead salt uniting with the sulphuric acid out of the alum to form lead sulphate, which precipitates to the bottom. The clear solution contains alumina in the form of acetate, and this supplies the proofing quality to the fabric. It is applied in a form of machine shown in Fig. 8, which will be seen to consist of a trough containing the proofing solution, _C_, with a pair of squeezing rollers, _A_, over the top. The fabric is drawn down through the solution and up through the squeezers in the direction of the arrows. At the {747} back of the machine the cloth automatically winds itself onto a roll, _B_, and then only requires drying to develop the water-resisting power. _D_ is a weight acting on a lever which presses the two rollers, _A_, together. The water-repelling property is gained as follows:

Drying the fabric, which is impregnated with acetate of alumina, drives off some of the volatile acetic acid, leaving a film of basic acetate of alumina on each wool fiber. This basic salt is very difficult to wet, and has so little attraction for moisture that in a shower of rain the drops remain in a spheroidal state, and fall off. In a strong wind, or under pressure, water eventually penetrates through fabrics proofed in this manner; but they will effectually resist a sharp shower. Unfortunately, shower-proofed goods, with wear, gradually lose this property of repelling water. The equation representing the change between alum and sugar of lead is given below. In the case of common alum there would, of course, be potassium acetate in solution besides the alumina.

Alum. Sugar of lead.
Al_〈2〉K_〈2〉(So_〈4〉)_〈4〉 + 4 Pb(C_〈2〉H_〈3〉O_〈2〉)_〈2〉

Lead Potassium Aluminum
sulphate. acetate. acetate.
= 4 PbSo_〈4〉 + 2 KC_〈2〉H_〈3〉O_〈2〉 + Al_〈2〉(C_〈2〉H_〈3〉O_〈2〉)_〈6〉

Now that sulphate of alumina is in common use, alum need not be used, as the potash in it serves no purpose in proofing.

There are many compositions conferring water resisting powers upon textiles, but unfortunately they either affect the general handle of the material and make it stiff, or they stain and discolor it, which is equally bad. A large range of waterproof compositions can be got by using stearates of the metals; these, in nearly every case, are insoluble bodies, and when deposited in the interior of a fabric form a water-resisting “filling” which is very effective. As a rule these stearates are deposited on the material by means of double baths; for example, by passing the fabric through (say) a bath of aluminum acetate, and then, after squeezing out the excess of liquid, passing it through a bath of soap. The aluminum salt on the fabric decomposes the soap, resulting in a deposit of insoluble stearate of alumina. This system of proofing in two baths is cleaner and more economical than adding all the ingredients together, as the stearate formed is just where it is required “on the fibers,” and not at the bottom of the bath.

One of the most important patents now worked for waterproofing purposes is on the lines of the old alumina process. In this case the factor used is rosin, dissolved in a very large bulk of petroleum spirit. The fabrics to be proofed (usually dress materials) are passed through a bath of this solution, and carefully dried to drive off the solvent. Following this, the goods are treated by pressing with hot polished metal rollers. This last process melts the small quantity of rosin, which is deposited on the cloth, and leaves each single fiber with an exceedingly thin film of rosin on it. It will be understood that only a very attenuated solution of rosin is permissible, so that the fibers of the threads and not the threads themselves are coated with it. If the solution contains too much rosin the fabric is stiffened, and the threads cemented together; whereas if used at the correct strength (or, rather, weakness) neither fabric nor dye suffers, and there is no evidence of stickiness of any description.

Fig. 9 shows a machine used for spreading a coat of either proofing or any other fluid on one side of the fabric. {748} This is done by means of a roller, _A_, running in the proofing solution, the material to be coated traveling slowly over the top and just in contact with the roller, _A_, which transfers the proofing to it. Should the solution used be of a thick nature, then a smooth metal roller will transfer sufficient to the fabric. If the reverse is the case, and the liquid used is very thin, then the roller is covered with felt, which very materially adds to its carrying power. As shown in Fig. 9, after leaving the two squeezing rollers, _BB_, the fabric passes slowly round a large steam-heated cylinder, _C_, with the coated side uppermost. This dries the proofing and fastens it, and the cloth is taken off at _D_.

Besides stearates of the metals, glues and gelatins have been used for proofing purposes, but owing to their stiffening effect, they are only of use in some few isolated cases. With glue and gelatin the fixing agent is either tannic acid or some metallic salt. Tannic acid converts gelatin into an insoluble leather-like body; this can be deposited in the interstices of the fabric by passing the latter through a gelatin bath first, and then squeezing and passing through the tannic acid. Bichromate of potash also possesses the property of fixing the proteid bodies and rendering them insoluble.

The following are special processes used to advantage in the manufacture of waterproof fabrics:

I.—Ordinary Fabrics, Dressing Apparel, etc.—Immerse in a vat of acetate of alumina (5° Bé.) for 12 hours, lift, dry, and let evaporate at a temperature of from 140° to 149° F.

II.—Sailcloth, Awnings, Thick Blankets, etc.—Soak in a 7 per cent solution of gelatin at 104° F., dry, pass through a 4 per cent solution of alum, dry again, rinse in water, and dry.

III.—Fabrics of Cotton, Linen, Jute, and Hemp.—Put into a bath of ammoniacal cupric sulphate of 10° Bé. at a temperature of 87° F.; let steep thoroughly, then put in a bath of caustic soda (20° Bé.) and dry. To increase the impermeability, a bath of sulphate of alumina may be substituted for the caustic-soda bath.

IV.—Saturate the fabrics with the following odorless compound, subjecting them several times to a brushing machine having several rollers, where the warp threads will be well smoothed, and a waterproof product of fine sheen and scarcely fading will be the result. The compound is made with 30 parts, by weight, of Japan wax, 22 1/2 parts, by weight, of paraffine, 12 parts, by weight, of rosin soap, 35 parts, by weight, of starch, and 5 parts, by weight, of a 5 per cent solution of alum. Fabrics thus prepared are particularly adapted to the manufacture of haversacks, shoes, etc.

V.—White or Light Fabrics.—Pass first through a bath of acetate of alumina of 4° to 5° Bé. at a temperature of 104° F., then through the rollers to rid of all liquid; put into a warm solution of soap (5 parts, by weight, of olive-oil soap to 100 parts, by weight, of fresh water) and finally pass through a 2 per cent solution of alum, dry for 2 or 3 days on the dropping horse, and brush off all particles of soap.

VI.—Dissolve 1 1/2 parts, by weight, of gelatin in 50 parts, by weight, of boiling water, add 1 1/2 parts, by weight, of scraped tallow soap and 2 1/2 parts, by weight, of alum, the latter being put in gradually; lower the temperature of the bath to 122° F., lift out the fabric, dry, and calender.

VII.—Tent Cloth.—Soak in a warm solution of 1 part, by weight, of gelatin, 1 part, by weight, of glycerine, and 1 part, by weight, of tannin in 12 parts, by weight, of wood vinegar (pyroligneous acid) of 12° Bé. The whole is melted in a kettle and carefully mixed. The mass is poured into the receiver of the brushing machine, care being taken to keep it liquid. For a piece of 500 feet in length and 20 inches in width, 50 to 80 parts, by weight, of this compound are needed.

VIII.—To freshen worn waterproof material, cover with the following: Fifty-five thousand parts, by weight, of gelatin; 100 parts, by weight, of bichromate of potash; 100 parts, by weight, of acetic acid (to keep glue from congealing), and from 3,000 to 5,000 parts, by weight, of water; to this add 500 parts, by weight, of peroxide of ammoniacal copper, 100° Bé. This compound is put on the fabric with a brush and then exposed to air and light.

IX.—Soft Hats.—The hats are stiffened as usual, then put through the following three baths: Dissolve 1/2 part, by weight, of tallow soap in from 40 to 50 parts, by weight, of warm water (140° F.). Put 3 to 4 dozen hats into this solution, leave them in it for half an hour, then take out and put them as they are into another bath prepared with 40 to 50 parts, by weight, of water and 1/2 part, by weight, of alum and heated to 86° to 104° F. After {749} having been left in the second bath for 1/4 or 1/2 hour, take out as before, put into the third bath of 40 to 50 parts, by weight, of water, 1/2 part, by weight, of alum, and about 13 parts, by weight, of fish glue. In this cold bath the hats are left for another 1/2 hour or more until they are completely saturated with the liquid, then dried and the other operations continued.

X.—Woolen cloth may be soaked in a vat filled with aluminum acetate, of 5° Bé., for 12 hours, then removed, dried, and dried again at a temperature of 140° F.

XI.—Wagon covers, awnings, and sails are saturated with a 7 per cent gelatin solution, at a temperature of 104° F., dried in the air, put through a 4 per cent solution of alum, dried again in the air, carried through water, and dried a third time.

XII.—Cotton, linen, jute, and hemp fabrics are first thoroughly saturated in a bath of ammonio-cupric sulphate, of 10° Bé., at a temperature of 77° F., then put into a solution of caustic soda, 2° Bé., and dried. They may be made still more impervious to water by substituting a solution of aluminum sulphate for the caustic soda.