An Australian Railway Viaduct.—The Werribee Viaduct, in the colony of Victoria, is the longest work of the kind in Australia. The structure consists of lattice-girder work. It is 1,290 feet in length, and runs to a height of 125 feet above the level of the Werribee river. The viaduct has fifteen spans each of 60 feet, and thirteen spans of 30 feet. The total cost of the bridge was £600,000.
The Sharpening of Tools.—Instead of oil, which thickens and smears the stone, a mixture of glycerine and spirit is recommended. The proportions of the composition vary according to the class of tool to be sharpened. One with a relatively large surface is best sharpened with a clear fluid, three parts of glycerine being mixed with one part of spirit. A graver having a small cutting surface only requires a small pressure on the stone, and in such cases the glycerine should be mixed with only two or three drops of spirit.
Recipes for Plumbers.—Chloride of zinc, so much used in soldering iron, has, besides its corrosive qualities, the drawback of being unwholesome when used for soldering the iron tins employed to can fruit, vegetables and other foods. A soldering mixture has been found which is free from these defects. It is made by mixing one pound of lactic acid with one pound of glycerine and eight pounds of water. A wooden tank may be rendered capable of withstanding the effects of nitric or sulphuric acids by the following methods:—Cover the inside with paraffin; go over the inside with a sadiron heated to the temperature used in ironing clothes. Melt the paraffin under the iron so as to drive it into the wood as much as possible, then with a cooler iron melt on a coat thick enough to completely cover the wood. For brassing small articles: To one quart water add half an ounce each of sulphate copper and protochloride of tin. Stir the articles in the solution until the desired color is obtained. Use the sulphate of copper alone for a copper color. A good cement for celluloid is made from one part shellac dissolved in one part of spirit of camphor and three to four parts of ninety per cent. alcohol. The cement should be applied warm, and the broken parts securely held together until the solvent has entirely evaporated. Tin and tin alloys, after careful cleansing from oxide and grease, are handsomely and permanently bronzed if brushed over with a solution of one part of sulphate of copper (bluestone) and one part of sulphate of iron (copperas) in twenty parts of water. When this has dried, the surface should be brushed with a solution of one part of acetate of copper (verdigris) in acetic acid. After several applications and dryings of the last named, the surface is polished with a soft brush and bloodstone powder. The raised portions are then rubbed off with soft leather moistened with wax in turpentine, followed by a rubbing with dry leather.
Protecting Water-Pipes Against Frost.—A device has been brought forward for protecting water-pipes against freezing, the arrangement being based upon the fact that water in motion will remain liquid at a lower temperature than water at rest. One end of a copper rod, placed outside the building, is secured to a bracket, and the other end is attached to one arm of a weighted elbow lever; to the other arm of the lever is secured a rod which passes into the building and operates a valve in the water-pipe. By means of turn buckles the length of the copper rod can be adjusted so that before the temperature reaches the point at which there would be danger of the water in the pipes freezing the valve will be opened to allow a flow of water; beyond this point the valve opening will increase and the flow become more rapid as the cold becomes more intense, and as the temperature rises the valve is closed. This plan sets up a current in the pipes, which replaces the water as it grows cold by the warmer water from the main.
Destructive Work of Barnacles.—Unless some paint can be found which is proof against barnacles, it may be necessary to sheath steel vessels with an alloy of copper. An attempt has been made to cover the hulls with anti-corrosive paint and cover this with an outside coat which should resist the attack of barnacles. Somehow the barnacles eat their way through the paint and attach themselves to the hull. The vast item of expense attached to the dry-docking of steel ships makes this matter a not unimportant one. The barnacles interfere greatly with the speed of a vessel, and in a cruiser speed is of prime importance. They attach themselves in an incredibly short time to a steel hull, and it is not long before their effect can be noted by a comparison of the reading of the log.
How to Frost Glass.—Two ounces of spirits of salts, two ounces of oil of vitriol, one ounce of sulphate of copper, one ounce of gum arabic, mixed together and dabbed on with a brush; or this:—Dab your squares regularly over with putty; when dry go over them again—the imitation will be executed. Or this:—Mix Epsom salts with porter and apply it with a brush. Or this one:—Grind and mix white lead in three-fourths of boiled oil, and one-fourth of spirits of turpentine, and, to give the mixture a very drying quality, add sufficient quantities of burnt white vitriol and sugar of lead. The color must be made exceedingly thin, and put on the panes of glass with a large painting-brush in as even a manner as possible. When a number of the panes are thus painted take a dry duster, quite new, dab the ends of the bristles on the glass in quick succession till you give it a uniform appearance; repeat this operation till the work appears very soft, and it will then appear like ground glass. When the windows require fresh painting, get the old coat off first by using strong pearlash water.
How to Preserve Posts.—Wood can be made to last longer than iron in the ground, if prepared according to the following recipe:—Take boiled linseed oil and stir in pulverized coal to the consistency of paint. Put a coat of this over the timber, and there is not a man that will live to see it rot.
What Diamond Dyes and Paints Are Made of.—Solutions of the aniline colors.
What the Ingredients Are of Soapine and Pearline.—They consist of partly effloresced sal soda mixed with half its weight of soda ash. Some makers add a little yellow soap, coarsely powdered, to disguise the appearance, and others a little carbonate of ammonium or borax.
How Many Thousand Feet of Natural Gas are Equal in Heat-Creating Power to One Ton Anthracite Coal.—About 40,000 cubic feet.