This alloy, used for printers' type, is often composed of 6 parts lead, and 2 antimony. It is of a blackish-grey colour, and is softer than tin and copper, but a little harder than lead. Several of these alloys, having the following compositions by weight:-
Lead .. ..
have been submitted to a new examination by F. de Jussieu, who has published his results in a pamphlet of some scientific interest, printed at Autun. Every scientific metallurgist acquainted with the singular properties of precipitated metallic antimony, as published some years ago by Gore, will be prepared to expect many remarkable properties of that metal and its alloys, which as yet have been but imperfectly studied, though the metal itself, in a state of imperfect purity, has been known since the 15th century, when its powerful medicinal properties were first ascertained and employed by Basil Valentine and Paracelsus. The chief portion of de Jussieu's pamphlet is devoted to the experimental recognition and exposition of facts of interest to the purely scientific metallurgist, and especially in reference to the liquation and crystallization upon reduction of temperature of these alloys; but there are a few things intercalated which may prove of practical importance. Amongst these is the fact that those alloys of lead and antimony, whose constituents are the same in kind as common type-metal, are susceptible of assuming a high degree of hardness when rapidly cooled against a cold metallic surface, showing a perfect analogy with the property of hardening by chilling eminently possessed by certain cast-irons, but more or less shown by all known varieties of that metal.
Fesquet gives the following combinations :-
Large type: (a) 10 lead, 2.5copper;
(5) 9 lead, 1 antimony, 0*5 arsenic; (c) 8 copper, 2 tin, 0*5 bismuth; (d) 2 copper, 2 tin, 2 bismuth; (e) 73 copper, 27 zinc; (f) 5 copper, 67 zinc, 25 tin, 3 nickel; (g) 12 tin, 16 zinc, 64 lead, 8 antimony.
Music plates : (a) 5 to 7. 5 tin, 5 to 2. 5 antimony; (6) 16 lead, 1 antimony; (c) 8 lead, 2 antimony, 1.5 tin; (d) 4 lead, 2 antimony, 1 zinc; (e) 7.5 lead, 2•5 antimony, 0.5 copper.
Printing type: 4 parts lead, 1 antimony.
Small type and Stereotypes: (a) 9 parts lead, 2 antimony, 2 bismuth;
(6) 16 lead, 4 antimony, 5 tin. (c) For every 6 lb. of lead add 1 lb. antimony. The antimony should be broken into very small pieces, and thrown on the top of the lead when it is at red heat. The cheapest and simplest mode of making a stereotype metal is to melt old type, and to every 14 lb. add about 6 lb. of grocers' tea-chest lead. To prevent any smoke arising from the melting of tea-chest lead, it is necessary to melt it over an ordinary fire-place, for the purpose of cleansing it, which can be done by throwing in a small piece of tallow about the size of a nut, and stir it briskly with the ladle, when the impurities will rise to the surface, and can be skimmed off. In the mixing of lead and type-metal, see that there are no pieces of zinc amongst it, the least portion of which will spoil the whole of the other metal that is mixed with it. Zinc is of a bluish-white colour; its hue is intermediate between that of lead and tin. It takes about 80° more heat than lead to bring it into fusion; therefore should any metal float on the top of the lead, do not try to mix it, but immediately take it off with the ladle.