Part 188

During the process of deposition, the pieces should be moved about in the bath as much as possible in order to preserve the homogeneity of the liquid. If this be not attended to, stratification and circulation of the liquid is produced by the decomposition of the anode, and is rendered visible by the appearance of long, vertical lines on the cathode.

For amateurs and others performing small and occasional experiments, the following simple apparatus will be serviceable. Place the solution of sulphate of copper in an earthenware or porcelain jar, in the center of which is a porous pot containing amalgamated zinc and a solution of sulphuric acid and water, about 2 or 3 parts in 100. At the top of the zinc a brass rod is fixed, supporting a circle of the same metal, the diameter of which is between that of the containing vessel and the porous pot. From this metallic circle the pieces are suspended in such a manner that the parts to be covered are turned toward the porous pot. Two small horsehair bags filled with copper sulphate crystals are suspended in the solution to maintain its saturation.

«ELM TEA.»

Powdered slippery elm bark 2 teaspoonfuls (or the equivalent in whole bar) Boiling water 1 cup Sugar, enough. Lemon juice, enough.

Pour the water upon the bark. When cool, strain and flavor with lemon juice and add sugar. This is soothing in case of inflammation of the mucous membrane.

«EMBALMING FLUIDS.»

Success in the use of any embalming fluid depends largely on manipulation, an important part of the process being the thorough removal of fluid from the circulatory system before undertaking the injection of the embalming liquid.

I.—Solution zinc chloride (U. S. P.) 1 gallon Solution sodium chloride 6 ounces to pint 6 pints Solution mercury bichloride, 1 ounce to pint 4 pints Alcohol 4 pints Carbolic acid (pure) 8 ounces Glycerine 24 fluidounces

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Mix the glycerine and carbolic acid, then all the other ingredients, when a clear solution of 3 gallons results, which is the proper amount for a body weighing 150 pounds.

II.—Arsenious acid 100 parts Sodium hydrate 50 parts Carbolic acid and water, of each a sufficient quantity.

Dissolve the arsenious acid and the soda in 140 parts of water by the aid of heat. When the solution is cold, drop carbolic acid into it until it becomes opalescent, and finally add water until the finished product measures 700 parts.

III.—Salicylic acid 4 drachms Boric acid 5 drachms Potassium carbonate 1 drachm Oil of cinnamon 3 drachms Oil of cloves 3 drachms Glycerine 5 ounces Alcohol 12 ounces Hot water 12 ounces

Dissolve the first 3 ingredients in the water and glycerine, the oils in the alcohol, and mix the solutions.

IV.—Thymol 15 grains Alcohol 1⁠/⁠2 ounce Glycerine 10 ounces Water 5 ounces

V.—Cooking salt 500 parts Alum 750 parts Arsenious acid 350 parts Zinc chloride 120 parts Mercury chloride 90 parts Formaldehyde solution, 40 per cent 6,000 parts Water, up to 24,000 parts

VI.—Arsenious acid 360 grains Mercuric chloride 1 1⁠/⁠4 ounces Alcohol 9 ounces Sol. ac. carbolic, 5 per cent 120 ounces

From 10 to 12 pints are injected into the carotid artery—at first slowly and afterwards at intervals of from 15 to 30 minutes.

EMERALD (IMITATION): See Gems, Artificial.

«EMERY:»

«Emery Grinder.»—Shellac, melted together with emery and fixed to a short metal rod, forms the grinder used for opening the holes in enameled watch dials and similar work. The grinder is generally rotated with the thumb and forefinger, and water is used to lubricate its cutting part, which soon wears away. The grinder is reshaped by heating the shellac and molding the mass while it is in a plastic condition.

«Preparing Emery for Lapping.»—To prepare emery for lapping screw-gages, plugs, etc., fill a half-pint bottle with machine oil and flour emery, 7 parts oil to 1 part emery, by bulk. Mix thoroughly and let stand for 20 minutes to settle. Take the bottle and pour off one-half the contents without disturbing the settlings. The portion poured off contains only the finest emery and will never scratch the work.

For surface lapping put some flour emery in a linen bag and tie up closely with a string. Dust out the emery by striking the bag against the surface plate; use turpentine for rough lapping and the dry surface plate for finishing.

«Removing Glaze from Emery Wheels.»—If the wheel is not altogether too hard, it can sometimes be remedied by reducing the face of the wheel to about 1⁠/⁠8 inch, or by reducing the speed, or by both. Emery wheels should be turned off so that they will run true before using. A wheel that glazes immediately after it has been turned off, can sometimes be corrected by loosening the nut, and allowing the wheel to assume a slightly different position, when it is again tightened.

«Emery Substitute.»—For making artificial emery, 1,634 parts of the following substances may be employed: Seven hundred and fifty-nine parts of bauxite, 700 parts of coke, and 96 parts of a flux, which may be a carbonate of lime, of potash, or of soda, preferably carbonate of lime on account of its low price. These materials are arranged in alternate layers and fused in an oven having a good draught. They are said to yield an artificial emery similar to the natural emery of Smyrna and Naxos, and at low cost.

«EMULSIFIERS:»

«Rosin Soap as an Emulsifier.»—The soap should be made by boiling gently for 2 hours, in an evaporating dish, a mixture of 1,800 grains rosin and 300 caustic soda with 20 fluidounces water. Upon cooling, the soap separates as a yellow mass, which is drained from the liquid, squeezed, then heated on a water bath until it is dry and friable. Fixed oils may be emulsified by adding 1 ounce {290} to a solution of 10 grains soap in 1 ounce water. Volatile oils require 10 grains rosin soap, 2 3⁠/⁠4 ounces water, and 2 drachms oil. Creosote requires double this amount of soap. Thymol may be rendered miscible with water by dissolving 18 grains together with 20 grains soap in 3 fluidounces alcohol, then adding enough water to make 6 fluidounces. Of course many other substances may be emulsified with the same emulsifier.

«Yolk of Egg as an Emulsifier.»—The domestic ointment of Unona, consisting of a mixture of oil and yolk of egg, is miscible in all proportions with water. It is proposed to utilize this fact by substituting a diluted ointment for the gum emulsions in general use, the following being given as a general formula: