The Scientific American cyclopedia of formulas : partly based upon the twenty-eighth edition of Scientific American cyclopedia of receipts, notes and queries 15,000 formulas / edited by Albert A. Hopkins.

Albert A. Hopkins

Date:: 1910

Credit: The Scientific American cyclopedia of formulas : partly based upon the twenty-eighth edition of Scientific American cyclopedia of receipts, notes and queries 15,000 formulas / edited by Albert A. Hopkins. Source: Wellcome Collection.

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$(Gold Imitations) (Lead Alloys) est pitch and 18 parts of platinum black added. Platinum and Copper.—1.—Golden-Yel¬ low Alloys of.—Alloys whose composition is such that they resemble pure gold in color are well suited to the manufacture of jewelry and other ornamental articles. They can be prepared for about twice the cost of silver, and are not only much cheaper than gold, and equally beautiful in color, but considerably more durable. The composition of these alloys of plati¬ num and copper, employed in making jew¬ elry, varies exceedingly. A few of the compositions are here given : I. II. III. IV. Platinum. 2 20 7 3 Copper. 5 . . 16 13 Zinc. . . 1 Silver. 1 20 Brass. 2 240 Nickel. 1 120 The alloy numbered IV, called Cooper’s gold, is most excellent for manufacturing jewelry, since its color cannot be distin¬ guished from that of 18-carat gold, even by close comparison. It can be drawn out without difficulty to the finest wire, and rolled into very thin sheets. 2.—Other alloys of the same nature are composed as follows : I. II. III. -IV. Platinum. 15 16 7 6 Coi>per. 10 7 16 23 Zinc . 1 1 1 The successful preparation of these al¬ loys depends upon one condition, namely, that the metals shall be entirely free from iron. If this is not the case, the alloys will indeed show the requisite color, but will be too hard, and so brittle that they cannot be drawn out into thin sheet or fine wire. It has been found by ac¬ curate experiment that a very small per¬ centage of iron is sufficient to lessen the ductility considerably ; an 8-1000 part of the weight of the alloy will make it no¬ ticeably brittle. The metals used in pre¬ paring the alloy must, therefore, be test¬ ed beforehand for the presence of iron, and any which contain the slightest trace of it excluded. Prince’s Metal.—A name given to vari¬ ous yellow alloys varying from 60 to 75% of copper and 40 to 25% of zinc. Tombac.—1.—An alloy consisting of copper, 16 lb.; tin, 1 lb.; zinc, 1 lb. Red tombac is composed of copper, 10 lb.; zinc, 1 lb. 2.—Copper, 16 lb.; tin, 1 lb.; zinc, 1 lb. Tournay’s Metal.—This alloy is char¬ acterized by great ductility, and is much used on this account by the Paris manu¬ facturers of bronze articles, and for the manufacture of imitation jewelry from thin sheets, for pressed buttons, etc. It is composed of copper, 82.54 parts ; zinc, 17.46 parts. Unalterable Alloy {Jacobi).—Copper, 70 to 73% ; tin, 2 to 11% ; lead, 15 to 20%; zinc, 0.5. to 1%. This alloy pos¬ sesses a yellowish red tint, and may be used for objects of art, imitation jewelry, etc. When treated with sulphides, chlo¬ ride of antimony, chloride of arsenic, etc., this alloy becomes coated with a black patina, capable of being polished. IRON Ferro-manganese is a variety of metal specially manufactured in a blast furnace from ores rich in oxide of manganese, and is very extensively used in the manufac¬ ture of mild steel. When the pig iron contains less than about 20% manganese its fracture shows large crystalline cleav¬ age planes, and it is then termed spie- geleisen. The variety known as ferro¬ manganese is a hard, crystalline body, but the fractured surface does not present the large cleavage planes so characteristic of spiegeleisen. It contains from 20 to 85% of manganese. Glass Molds, Alloy for Casting.—Iron, 100 parts ; nickel, 15 parts. Sideraphite.—Iron, 63 parts ; nickel, 23 parts; tungsten, 4 parts; aluminum, 5 parts; copper, 5 parts. LEAD Bullet Metal.—Lead, 98 parts ; arsenic, 2 parts. For round shot, the fused metal is dropped from a high elevation in a shot tower into a basin of water; or thrown down a stack of limited height, in which a strong draught of air is pro¬ duced by a blower. Calin.—The lining of tea chests is called calin. It is composed of lead, 50 to 60 parts; tin, 8 parts ; copper, % part; and a small percentage of zinc. Leading, Hot Alloys for.—Tin, 3 parts ; lead, 17 parts. Magnolia Metal.—Lead, 840 parts; an¬ timony, 7y2 parts; tin, 2% parts ; bis¬ muth, V8 part; aluminum, % part; graph¬ ite, Vs part. Patent Sheathing for Ships.— (Baron Wetterstedt.)—This consists of lead with from 2 to 8% of antimony. Usually about 3% is used. [103]$