Part 25

«To Render Gum Arabic More Adhesive.»—I.—Add crystallized aluminum sulphate in the proportion of 2 dissolved in 20 parts of water to 250 parts of concentrated gum solution (75 parts of gum in 175 parts of water).

II.—Add to 250 parts of concentrated gum solution (2 parts of gum in 5 parts of water) 2 parts of crystallized aluminum sulphate dissolved in 20 parts of water. This mixture glues even unsized paper, pasteboard on pasteboard, wood on wood, glass, porcelain, and other substances on which labels frequently do not adhere well.

«Envelope Gum.»—The gum used by the United States Government on postage stamps is probably one of the best that could be used not only for envelopes but for labels as well. It will stick to almost any surface. Its composition is said to be the following:

Gum arabic 1 part Starch 1 part Sugar 4 parts Water, sufficient to give the desired consistency.

The gum arabic is first dissolved in some water, the sugar added, then the starch, after which the mixture is boiled for a few minutes in order to dissolve the starch, after which it is thinned down to the desired consistency.

Cheaper envelope gums can be made by substituting dextrine for the gum arabic, glucose for the sugar, and adding boric acid to preserve and help stiffen it.

«Mucilage to Make Wood and Pasteboard Adhere to Metals.»—Dissolve 50 parts, by weight, of lead acetate together with 5 parts, by weight, of alum in a little water. Make a separate solution of 75 parts, by weight, of gum arabic in 2,000 parts, by weight, of water, stir in this 500 {44} parts, by weight, of flour, and heat slowly to boiling, stirring the while. Let it cool somewhat, and mix with it the solution containing the lead acetate and alum, stirring them well together.

«Preservation of Gum Solution.»—Put a small piece of camphor in the mucilage bottle. Camphor vapors are generated which kill all the bacterial germs that have entered the bottle. The gum maintains its adhesiveness to the last drop.

ADULTERANTS IN FOODS: See Foods.

ADUROL DEVELOPER: See Photography.

ÆSCO-QUININE: See Horse Chestnut.

AGAR AGAR PASTE: See Adhesives.

«AGATE, BUTTONS OF ARTIFICIAL.»

Prepare a mixture or frit of 33 parts of quartz sand, 65 parts calcium phosphate, and 2 parts of potash. The frit, which has been reduced by heat to the fusing point, is finely ground, intimately mingled with a small quantity of kaolin and pressed in molds which yield button-shaped masses. These masses, after having been fired, are given a transparent glaze by any of the well-known processes.

AGATE (IMITATION): See Gems, Artificial.

AGING OF SILK: See Silk.

AGING, SILVER AND GOLD: See Plating.

«AIR BATH.»

This air bath is employed in cases in which, upon drying or heating substances, acid vapors arise because the walls of the bath are not attacked by them. For the production of the drying apparatus take a flask with the bottom burst off or a bell jar tubulated above. This is placed either upon a sand bath or upon asbestos paper, previously laid upon a piece of sheet iron. The sand bath or the sheet iron is put on a tripod, so that it can be heated by means of a burner placed underneath. The substance to be dried is placed in a glass or porcelain dish, which is put under the bell jar, and if desired the drying dish may be hung on the tripod. For regulating the temperature the tubulure of the jar is closed with a pierced cork, through whose aperture the thermometer is thrust. In order to permit the vapors to escape, the cork is grooved lengthwise along the periphery.

AIR BUBBLES IN GELATINE: See Gelatine.

AIR, EXCLUSION OF, FROM SOLUTIONS: See Photography.

«AIR-PURIFYING.»

«Ozonatine» is a fragrant air-purifying preparation consisting of dextrogyrate turpentine oil scented with slight quantities of fragrant oils.

ALABASTER CLEANING: See Cleaning Preparations and Methods.

ALBATA METAL: See Alloys.

«ALBUMEN IN URINE, DETECTION OF.»

Patein (Pharm. Zeit.) recommends the following test for albumen in urine: Dissolve 250 grams of citric acid in a sufficient quantity of water, add enough ammonia to neutralize, then 50 grams of alcohol, and finally enough water to make 1 liter. To the acid (or acidulated) urine, one-tenth its volume of the ammonium-citrate solution made as above is added, and the whole heated in the usual manner. The appearance of the faintest turbidity is said to indicate with positive certainty the presence of albumen.

ALBUMEN PAPER: See Photography.