Page:Popular Science Monthly Volume 27.djvu/557

Rh strength, toughness, and hardness, the facility with which it can he cast, and the soundness and uniformity of the castings produced. This quality is used for wheel-gearing, supports and connections of machines, crank-pin brasses, the shells of main and other bearings of engines, axle-boxes, and parts of locomotive-engines. It is also adapted for statuary and for large bells. Its most important application appears to be for making screw-propellers, for which, in its qualities of strength, non-corrosiveness, and perfect trueness in casting, it seems to be superior to any other substance yet found.

The qualities numbers four and five have no particular claim to strength, but are useful for bearings, slide-valves, slide-blocks, piston rings, and other purposes in which friction has to be taken account of.

Delta-metal, the second and latest example of the successful addition of iron to bronze, was introduced, in 1883, by Mr. Alexander Dick, who named it with the Greek equivalent for the initial of his surname. His preliminary experiments were directed to removing the inequalities in the properties of the iron-bronze alloys previously attempted, and he found that all depended on getting exactly the right proportion of iron and preventing its oxidation during the process of remelting. Delta-metal in color resembles gold alloyed with silver. It can be worked hot and cold. When melted, it runs freely, and the castings produced from it are sound and of a fine, close grain. It can not be welded, but can be brazed, and, when of suitable thickness, "burned." The varieties designed for working hot are capable of being stamped or punched, similar to wrought-iron and steel, into a variety of articles which have hitherto been cast in bronze or brass. This property is of much importance, for the articles thus turned out are cheaper and stronger than brass-castings. The iron introduced into the compound by Mr. Dick's process is really chemically combined; and the alloy does not rust, and has no action on the magnetic needle. Delta metal may be used to replace the best brass and gun-metal, and in many instances iron and steel also—for parts of rifles, guns, and torpedoes, tools for gunpowder-mills, parts of bicycles, gongs, various domestic articles, spindles for steam-and water-valves, plungers, pump rods, and boats.

Phosphor-copper is a preparation devised by Mr. W. G. Otto, of Darmstadt, for the purpose of furnishing engineers and founders with a compound, by adding certain proportions of which to a given bulk of metal they can obtain a phosphor-bronze suitable for various purposes.

An article called phosphor-manganese-bronze is in the market, but the manufacturer has not furnished a description of it.

Phosphor-lead bronze, introduced in 1881 by Messrs. K. H. Kuhne & Co., of Löbau, near Dresden, is regarded as specially adapted for all purposes where metal is subjected to constant wear or continuous friction. The introduction of lead into its composition and its homogeneousness are said to give it special properties, by reason of which