toughness are such that it does not even crack when distorted by this load. It is so ductile and malleable that it can be drawn down under a hammer to the fineness of a cambric needle. It works well, casts well, holds a fine surface under the tool, and when exposed to the weather it is in every respect considered the best bronze yet known. Its high cost alone has prevented its extensive use in the arts. The alloys are very uniform in character. Even one per cent. of aluminium added to copper causes a considerable increase in ductility, increases its fusibility, and enables it to cast well; two per cent. gives a mixture used for castings which are to be worked with a chisel. It is softened by sudden cooling from a red heat. Its coefficient of expansion is small at ordinary temperatures. It has great elasticity when made into springs." Guettier makes the following remarks:-* "Mr. Strange's experiments in regard to the relative rigidity of brass, ordinary bronze, and aluminium bronze showed that the latter was about forty times as rigid as soft brass and three times as rigid as ordinary bronze. Under the tool, aluminium bronze produces long and resisting chips, and although not entirely unoxidizable, it is not so easily tarnished by air as brass, bronze, or steel." Knight: "Aluminium bronze is more difficult *Metallic Alloys, by Guettier. American Mechanical Dictionary. to cut than brass, but cuts very smooth and clean. If less costly it would replace red and yellow brass. In contact with fatty matters or juice of fruit, no soluble metallic salt is formed, which highly recommends it for various articles of table use." Cowles Bros.* thus describe the alloys of aluminium and copper which they make : "In England the Aluminium Crown Metal Co. has for the past three or four years been turning out large quantities of aluminium alloys based on the price of $14.60 per pound for the aluminium in them. Even at the high prices charged, these Webster alloys have attained a great popularity, and are replacing German silver, brass, bronze, etc. Aluminium added to any of the common alloys, such as brass, German silver, or Britannia metal, adds greatly to all their desirable qualities. Aluminium bronze cannot only be used in all places where brass or bronze are now used, but it will likewise soon supersede iron and steel in many places; as for artillery. The maximum standard of strength demanded by the British and German governments in their wrought-steel guns, which cost from 50 cents to $1 per pound, is at present 70,000 pounds tensile strength and 15 per cent. elongation. These guns could be cast of aluminium bronze, giving a greater strength and elongation, at far less cost, being made in one-quarter of the *Cowles' Pamphlet, April, 1886. time and with a comparatively inexpensive plant. The melting-point of the bronze is somewhat below that of copper and its specific gravity is 7.23. It is without rival as an anti-friction metal, besides having the hardness, tenacity, and wearing qualities of the best steel. It has also the peculiar unctuousness of copper and lead, being so strong and tough that very small quantities of the rolled bronze may be used to bush boxes of cast or wrought iron, so that its first cost is less than that of the thick masses of brass or phosphor-bronze now used. The five per cent. bronze makes beautiful wearing plumbers' goods, and can be used also for table articles, being free from the offensive smell and taste peculiar to brass. Aluminium in almost all proportions up to eight per cent. improves all brasses. Some it makes more ductile, in others it improves the color, and all are greatly increased in strength and power to resist corrosion. The alloy copper 67, zinc 26, aluminium 7 has a strength of 96,000 pounds, while that of copper 67, zine 30, aluminium 3 has a strength of 65,000 pounds with 12 per cent. elongation. When we understand that ordinary brass rarely has a tensile strength over 30,000 pounds, the extraordinary value of the aluminium can be appreciated. The strength of these alloys on the testing machine is as follows: Average commercial cast brass 23,000 Less than 10.0 "The second alloy is made by mixing two parts five per cent. aluminium bronze with one part zinc. "The aluminium bronzes gave the following results: "The two 10 per cent. bronzes last given were plunged while red hot into water. Cowles Bros. are now selling 10 per cent. bronze at forty cents per pound." In regard to some alloys of aluminium and copper in which other metals are present, we would notice the following alloys which have been made in addition to those already incidentally mentioned. Aluminium can be melted with brass, argentan, etc., by which new bronzes are made of beautiful color, great hardness, and polish, unalterable in the air, easily cast, etc. One per cent. of aluminium is sufficient to modify the qualities of brass or tin bronze, while 2 per cent. shows a decided change. By taking ordinary bronze with 1 to 2 per cent. of zinc or tin, and adding 1 to 2 per cent. of aluminium, alloys are obtained possessing additional qualities to those of aluminium bronze, and which can replace it in places and for purposes where the latter's qualities are not so well suited. Besides these simple alloys we have those of copper with nickel, tin, zinc, bismuth, and aluminium, in such quantities as to make any desired color or degree of hardness. The following has a beautiful white polish, which is a close imitation of silver : Copper. Aluminium 100 23 7 F. H. Sauvage makes a metal resembling pure silver, which he calls Neogen. It contains- |