Part 272

Mix thoroughly.

«Remedies Against Mosquitoes.»—A remedy to keep off mosquitoes, etc., is composed as follows: Cinnamon oil, 1 part; patchouli oil, 1 part; sandal oil, 4 parts; alcohol, 400 parts. This has a pleasant odor.

Oil of pennyroyal is commonly used to keep mosquitoes away. Some form of petroleum rubbed on the skin is even more efficient, but unpleasant to use, and if left on long enough will burn the skin.

A 40 per cent solution of formaldehyde for mosquito bites gives remarkably quick and good results. It should be applied to the bites as soon as possible with the cork of the bottle, and allowed to dry on. Diluted ammonia is also used to rub on the bites.

«Roach Exterminators.»—Borax, starch, and cocoa are said to be the principal ingredients of some of the roach foods on the market. A formula for a poison of this class is as follows:

Borax 37 ounces Starch 9 ounces Cocoa 4 ounces

«Moth Exterminators.»—Cold storage is the most effective means of avoiding the ravages of moths. Where this is impracticable, as in bureau drawers, camphor balls may be scattered about with satisfactory result. The following is also effective:

Spanish pepper 100 parts Turpentine oil 50 parts Camphor 25 parts Clove oil 10 parts Alcohol, 96 per cent 900 parts

Cut the Spanish pepper into little bits, and pour over them the alcohol and oil of turpentine. Let stand 2 or 3 days, then decant, and press out. To the liquid thus obtained add the camphor and clove oil, let stand a few days, then filter and fill into suitable bottles. To use, imbibe bits of bibulous paper in the liquid and put them in the folds of clothing to be protected.

«Protecting Stuffed Furniture from Moths.»—The stuffing, no matter whether consisting of tow, hair, or fiber, as well as the covering, should be coated with a 10 per cent solution of sulphur in carbon sulphide. The carbon sulphide dissolves the sulphur so as to cause a very fine division and to penetrate the fibers completely.

«Powder to Keep Moths Away.»—

Cloves 2 ounces Cinnamon 2 ounces Mace 2 ounces Black pepper 2 ounces Orris root 2 ounces

Powder coarsely and mix well together.

«Book-Worms.»—When these insects infest books they are most difficult to deal with, as the ordinary destructive agents injuriously affect the paper of the book. The books should be well beaten and exposed to the sun, and a rag moistened with formalin passed through the binding and the covers where possible. In other cases the bottom edge of the binding should be moistened with formalin before putting on the shelves, so that formaldehyde vapor can be diffused.

INSECT POWDERS: See Insecticides.

«INSECT TRAP.»

Into a china wash-basin, half filled with water, pour a glass of beer; cover the basin with a newspaper, in the center of which a small round hole is cut. Place it so that the edges of the paper lie on the floor and the hole is over the center of the basin. At night beetles and other insects, attracted by the smell of beer, climb the paper and fall through the hole into the liquid.

INSTRUMENT ALLOYS: See Alloys.

INSTRUMENT CLEANING: See Cleaning Preparations and Methods.

INSTRUMENT LACQUER: See Lacquers.

«Insulation»

«ELECTRIC INSULATION:»

«Insulating Varnishes.»—For earth cables and exposed strong current wires:

I.—Melt 2 parts of asphalt together with 0.4 parts of sulphur, add 5 parts of linseed-oil varnish, linseed oil or cottonseed oil, keep at 320° F. for 6 hours; next pour in oil of turpentine as required.

II.—Maintain 3 parts of elaterite with 2 parts of linseed-oil varnish at 392° F. for 5 to 6 hours; next melt 3 parts of asphalt, pour both substances together, and again maintain the temperature of {426} 392° F. for 3 to 4 hours, and then add 1 part of linseed-oil varnish and oil of turpentine as required.

III.—Insulating Varnish for Dynamos and Conduits with Low Tension.—Shellac, 4 parts; sandarac, 2 parts; linoleic acid, 2 parts; alcohol, 15 parts.

IV.—An insulating material which contains no caoutchouc is made by dissolving natural or coal-tar asphalt in wood oil, adding sulphur and vulcanizing at 572° F. The mixture of asphalt and wood oil may also be vulcanized with chloride of sulphur by the ordinary process used for caoutchouc. Before vulcanizing, a solution of rubber scraps in naphthalene is sometimes added and the naphthalene expelled by a current of steam. Substitutes for hard rubber are made of natural or artificial asphalt combined with heavy oil of tar and talc or infusorial earth.

Most of the insulating materials advertised under alluring names consist of asphalt combined with rosin, tar, and an inert powder such as clay or asbestos. Some contain graphite, which is a good conductor and therefore a very undesirable ingredient in an insulator.