Pieces of this very difficult sort of workmanship are produced by overlaying and soldering together a certain number of plates of the said metals or alloys, by hammering, kneading, resoldering, filling up the hollow spaces with new metal, and repeating these operations many times; finally, when stretched out into a thin sheet, this composition shows the aforesaid pattern all composed of veins of the different metals that have been made use of. (11. Ap. Sci.)
Ludwig has made a number of analyses of ancient bronze implements, of great hardness, with the following results :-
Specimen No. 1 was a fragment of an axe from Maiersdorf. The metal was tenacious and bright yellow; hardness equal to that of apatite. No. 2: an axe from Linburg; reddish golden-yellow; tenacious and hardly scratched by felspar. No. 3: fragment of a sword from Steier; the metal was reddish-yellow, solid and tenacious, and not easily scratched by quartz. No. 4: a chisel from Peschiera; deep yellow, and containing a trace of cobalt. Neither zinc nor lead was found in any of the specimens. (Mech. Eng.)
Reichardt gives the following analysis of a sample of bronze found near Dant-zig, and constituting fragments of a ring or other ornament;-
This may be compared with others, as under:a. Bronze rings from Gallic sepulchral tumuli (Kopp).
b. Bronze from the bone caves of Perigord (Terreil).
c. Celtic bronze armlets from Aboyne (Church).
d. Bronze statue found at Brescia (Arnaudes).
e. Bronze from Messer, Siberia (Strove).
f. Celtic arrow heads (Olivier).
It thus appears that there are great differences in the composition of antique bronze even among different specimens found at the same place, the quantities of tin and of lead varying greatly.
A new alloy, which resembles silver, and is very ductile and malleable, is composed of 65 parts iron, 23 of nickel, 4 of tungsten, 5 of aluminium, and 5 of copper. The iron and the tungsten are melted together and then granulated, and the water into which the mixture is poured for this purpose must contain 1 lb. of slaked lime, and the same quantity of potash, to every gallon. The product formed by the fusion of the nickel, the copper, and the aluminium, is also granulated in water containing the same proportion of lime and potash; and during the melting the metals in the 2 crucibles roust be kept covered with a flux made of 2 parts borax and 2 of saltpetre. A piece of soda or potash, weighing about 1/2500 of the whole mass, is put into the crucible containing the copper, nickel, and aluminium, in order to prevent the oxidation of the last-named metal; and, to prevent the same action taking place with the copper, a small piece of charcoal is added. It is advisable before the operation of granulation to well stir the contents of the 2 crucibles. The granulated metals are dried, melted in the proportion given above, well shaken, and then run into bars.
The metal is called "sideraphthite." Another formula for its preparation is : 66 parts iron, 23 nickel, 5 copper, and 4 tungsten.
Lemarquand'8 inoxidizable alloy contains 750 copper, 140 nickel, 20 black oxide of cobalt, 18 rod tin, 72 pure zinc.
This alloy will adhere so firmly to metallic, glass, and porcelain surfaces, that it can be used as a solder, and is invaluable when the articles to be soldered are of such a nature that they cannot bear a high degree of temperature. It consists of finely pulverized copper or copper-dust, and is obtained by precipitating copper from the sulphate by means of metallic zinc: 20, 30, or 36 parts of this copper-dust, according to the hardness desired, are placed in a cast-iron or porcelain-linedmortar, and well mixed with some sulphuric acid having a specific gravity of 1.85. Add to the paste thus formed 70 parts (by weight) of mercury, constantly stirring. When thoroughly mixed, the amalgam must be carefully rinsed in warm water to remove the acid, then laid aside to cool. In 10 or 12 hours it will be hard enough to scratch tin. When it is to be used, it should be heated to a temperature of 707° F. (375° C), when it becomes as soft as wax by kneading it in an iron mortar. In this ductile state it can be spread upon any surface, to which, as it cools and hardens, it adheres very tenaciously.
This alloy melts at a lower degree of temperature than the one just described, and is very hard without being brittle. It consists of 6 parts bismuth, 3 zinc, and 13 lead. The 3 metals, after having been well melted and stirred together, should be poured into another melting-pot and melted again. This alloy cools with remarkably clear-cut edges, and if the articles made of it are dipped in dilute nitric acid, then rinsed in clear water, and polished with a woollen rag, the raised parts of the surface will have a fine polish, while the sunken parts will have a dark-grey, antique appearance, which forms a pretty contrast. The proportions of the different metals, dividing the alloy into 100 parts, are: 27.27 bismuth, 59.09 lead, 13.64 zinc.
Contains 6 parts bismuth, 3 tin, 13 lead. This alloy should be melted, run into bars, and laid aside till wanted, when it should be remelted. An alloy of 3 parts bismuth, 1 tin, 1 lead, for small castings, is harder, and yet it is not brittle. It can be finished with a contrasting surface of bright polish and dark grey, if it is washed in nitric acid, well diluted, rinsed, and polished with a woollen rag, as described in the alloy for small articles given above.