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
Licence: Public Domain Mark
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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![i (Gold Imitations) 2.—Copper, 100 parts; tin, 17 parts; magnesia, 6 parts; sal ammoniac, 3.6 parts; quicklime, 1.8 parts ; bitartrate of potash, 9 parts. The copper is melted first, and the magnesia, ammonia, lime and potash are successively added, in small quantities; finally the tin is intro¬ duced in fragments, and the whole fused for 35 minutes. Mosaic Gold, Chrysorin, Hamilton's Metal.—The above names are applied to an alloy composed, with slight deviations, of 100 parts of copper and 50 to 55 parts of zinc. It has a very beautiful color, closely resembling that of gold, and is distinguished by a very fine grain, which makes it especially suitable for the manu¬ facture of castings which are afterward to be gilded. The best method of obtain¬ ing a thoroughly homogeneous mixture of the two metals is to first put into the cru¬ cible one-half of the zinc to be used, place the copper upon it, and fuse the mixture under a cover of borax at as low a tem¬ perature as possible. Have ready the oth¬ er half of the zinc, cut into small pieces, and heated almost to melting, and when the contents of the crucible are liquid throw it in, a small portion at a time, stirring constantly to effect as intimate a mixture of the metals as possible. Oreide or Oroide, French Gold.—The so-called French gold, when polished, so closely resembles genuine gold in color that it can scarcely be distinguished from it. Besides its beautiful color it has the valuable properties of being very ductile and tenacious, so that it can easily be stamped into any desired shape; it also takes a high polish. It is frequently used for the manufacture of spoons, forks, etc., but is unsuitable for this purpose on ac¬ count of the large amount of copper con¬ tained in it, rendering it injurious to health. The directions for preparing this alloy vary greatly. The products of some Paris factories show the following com¬ position : I. II. III. Copper. 90 80.5 86.21 Zinc. 10 14.5 31.52 Tin..'. 0.48 Iron. 0.24 A special receipt for oreide is the fol¬ lowing : Melt 100 parts of copper, and add, with constant stirring, 6 parts of magnesia, 3.6 parts of sal ammoniac, 1.8 parts of lime and 9 parts of crude tartar. Stir again thoroughly, and add 17 parts of granulated zinc, and after mixing it with the copper by vigorous stirring, keep the alloy liquid for one hour. Then care- (Gold Imitations) fully remove the cover of froth and pour off the alloy. Ormolu, Or Moulu.—The French name for this alloy is obviously incorrect, inas¬ much as it is not cast gold, but really a gold-colored bronze, related in its com¬ position to that variety known as statu¬ ary bronze. It serves manifold purposes in industrial art, being used for statu¬ ettes and articles of ornament, as well as for candlesticks, inkstands, etc. An in¬ teresting application of it is in the manu¬ facture of articles to be enameled. The enamel is placed in shallow cavities chis¬ eled in the surface of the bronze, and melted by heating the latter. The edges of the cavities separate the different col¬ ors of the melted glass, and the articles, after heating, appear coated with the closely adhering enamel. This work is known by the French name of “email cloissonne.” Cloisonne articles were first introduced into European countries from China, but at the present day the Euro¬ pean work as far surpasses the Chinese as in the case of porcelain. Real ormolu is in itself of a pure golden yellow color, and therefore requires but little gold for gilding. It is composed of copper, 58.3 parts ; tin, 16.7 parts; zinc, 25.3 parts; and is used for the finest bronze articles of luxury. Pinchbeck-—1.—Pinchbeck was first manufactured in England. Its dark gold color is the best imitation of gold alloyed with copper. Being very ductile, it can easily be rolled out into thin plates, which can be given any desired shape by stamp¬ ing. It does not readily oxidize, and thus fulfils all the requirements for making cheap jewelry, which is its principal use. It is composed of copper and zinc, or copper, zinc and brass, in the proportions given: I. II. Copper. 88.8 93.6 Zinc . 11.2 6.4 or Copper. 2.0 1.28 Zinc... 0.7 Brass. 1.0 0.7 2.—Copper, 5 lb.; zinc, 1 lb. Platinor.—This is a name given to cer¬ tain alloys containing platinum of a golden yellow color, and consisting of platinum, copper, silver, zinc and nickel. An alloy of the color of gold, and said to be quite constant in air, is prepared as follows: Melt 10 parts of silver with 45 parts of copper, then add 18 parts of brass and 9 parts of nickel. The tem¬ perature must then be raised to the high- [102]](https://iiif.wellcomecollection.org/image/b31361523_0116.jp2/full/800%2C/0/default.jpg)
