Alloy
3 of the 7 encyclopedias on this shelf carry an entry for Alloy. Both are reproduced below, so you can see where they agree and where they differ.
Collier's New Encyclopedia (1921)
a compound or mixture of two or more metals. When mercury is mixed with another metal, the compound is termed an amalgam. Alloys are divided into three groups: (1) Those formed by the metals lead, tin, zinc, and cadmium, which impart to their alloys their own physical properties in the proportions in which they themselves are contained in the alloy. (2) Those formed by almost all other metals. (3) Those which contain metals found in both these groups of alloys. In every alloy lloy the sp specific heat and the coefficient of expansion are always the means of those of its component metals. But in other physical properties a variation takes place. This is the case with specific gravity, which, in alloys of the first group, is the mean of their constituent metals; but in those of the second group it is always greater or less than the mean specific gravity of their constituents. In some instances, when two melted metals are mixed together to form an alloy, an evolution of heat occurs which is believed to indicate that a chemical compound has been formed. This is the case with copper and zinc, copper and aluminum, platinum and tin, etc. The strength or cohesion of an alloy is generally greater than that of the mean cohesion of the metals contained therein or even of that of the most cohesive of its constituents. The most useful alloy in the arts is brass. This compound metal is next to iron in importance. There are some important alloys of copper and tin, among them bronze, gun metal, bell metal and speculum metal. these the proportions vary from equal parts of copper and tin to 10 parts of copper with 1 of tin. The most cohesive, that is, the strongest of them, is a bronze consisting of 6 parts of copper to 1 of tin. Phosphor bronze is an invention of recent years. The addition of from 0.25 to 2.5 per cent. of phosphorus to a bronze containing from 7 to 8 per cent. of tin gives it greater hardness, elasticity, and toughness. This alloy is now much used for parts of machinery. Pewter is a tin alloy which was more used formerly than now. Type metal is a compound of 50 parts of lead, 25 of antimony, and 25 of tin, but it varies slightly. Fusible metal melts at low temperatures; one kind is composed of 3 parts of tin, 5 of lead, and 8 of bismuth, and melts in hot water. This alloy is now a good deal employed in stereotyping, and in obtaining copies of woodcuts. Aluminum bronze, very closely resembling gold in appearance, is much used for pencil-cases, chains, and some larger objects. A compound of silver and aluminum is sometimes used for watch-springs, and for spoons and forks. Dentists use a very ductile alloy composed of 2 parts by weight of silver and 1 of platinum. When gold is to be used for coins, jewelry, or plate, it requires to be alloyed with copper or silver or with both, in order to harden it. Like silver, it is too soft when pure. There are five legal standards for articles made of gold i. e., alloyed gold apart from coin. These are called 22, 18, 15, 12, and 9 carat gold. That is to say, these figures represent the number of parts of pure gold in every 24 parts of the alloy used by the goldsmith or jeweler. English sovereigns are made of a mixture of 22 parts of gold to 2 of copper, and this is called 22-carat or standard gold. In Germany, Italy, and the United States, standard gold for the coinage is 21.6 carats. In the United States, it is declared by law that the standard for both gold and silver coins shall be such, that of 1,000 parts, by weight, 900 shall be of pure metal and 100 of alloy.
Aiton's Encyclopedia (1910)
a mixture of two or more metals brought about by melting them together. Copper is modified for special purposes by alloying it with other metals. The amount of other metals combined with copper in some of the common alloys may be stated as follows: Brass contains 30 to 40 per cent of zinc; bronze, 4 to 10 per cent of tin, 2 or more of zinc, and usually some lead; gun-metal, 9 per cent, and bell-metal, 25 per cent of tin; German silver, 20 to 40 per cent of zinc and 10 to 20 per cent of nickel. Among alloys not containing copper, soft solder contains 50 per cent each of tin and lead; pewter, 80 per cent of tin and 20 per cent of lead; type metal, 70 per cent of lead, 20 per cent of antimony, and 10 per cent of tin. The nickel alloy used in coining contains 75 per cent of copper and 25 per cent of nickel. Alloys in which mercury forms one of the components are known as amalgams. Of the common metals, iron is the least miscible with mercury. The principal coins of the United States are alloys of gold and silver with copper. In alloys of the noble metals, the degree of fineness is indicated by "carats." Pure gold is 24 carats fine. Gold 22 carats fine, means 22 parts of gold to 2 parts of some other metal. American, French, and German coins are 21.6 carat, or 90 per cent gold. 2026 Editor's Note: The alloys the article lists were about to multiply spectacularly: stainless steel arrived in 1913, aluminum alloys made the aircraft age possible, and today's jet engines run on 'superalloys' engineered almost atom by atom — an art the brass-and-bronze world of this entry only began. (Ed: BR 2026-06-06)
American Watchmaker and Jeweler (1892)
A compound of two or more metals. It is usual to melt the less fusible metal first and add the more fusible. Alloys for Compensation Balances. Breguet used for his compensation balances the following alloy: Silver, two parts, by weight; copper, two parts; zinc, one part. First melt the silver and throw in the zinc, reduced to small pieces, stirring the metals and leaving it on the fire for as short a time as possible to prevent the volatilization of the latter metal; then pour it out and let it get cold. Melt the copper and add the cold alloy, stirring the three together until intimately mixed. Pour out, cut into pieces, and smelt anew, to obtain a perfect incorporation. Be careful, however, to leave the alloy as short a time as possible over the fire, because the zinc dissipates easily. This alloy is hard, elastic, very ductile, and quickly smelts in the furnace. It does not stand much hammering. Alloy for Composition Files. These files, which are frequently used by watchmakers and other metal workers, for grinding and polishing, and the color of which resembles silver, are composed of 8 parts copper, 2 parts tin, 1 part zinc, 1 part lead. They are cast in forms and treated upon the grindstone; the metal is very hard, and therefore worked with difficulty with the file.