───────────────────┬──────┬──────┬──────┬──────┬──────┬──────┬───────────── │ Pt. │ Cu. │ Ag. │ Au. │ Ni. │ Pd. │ Other │ │ │ │ │ │ │Constituents. ───────────────────┼──────┼──────┼──────┼──────┼──────┼──────┼───────────── │Parts.│Parts.│Parts.│Parts.│Parts.│Parts.│ Parts. Jewellery alloys: │ │ │ │ │ │ │ Platinum alloy │ 1│ 0–1│ 2–5│ │ │ │ Platinor │ 2│ 5│ 1│ │ 1│ │Brass 2. Palladium alloy │ │ │ │ │ │ 9│Rhodium 1. Mock gold │ 7│ 16│ │ │ │ │Zinc 1. Mock gold │ 1│ │ 1│ │ 6│ │Brass 1. Mock gold │ 1│ 4│ │ │ │ │ Coopers’ pen metal:│ 4│ 1│ 3│ │ │ │ Watch alloy │ │ 13│ 11│ 18│ │ 6│ Watch alloy │ │ 25│ 4│ │ 1│ 70│ Watch alloy │ 63│ 18│ │ │ 17│ │Cadmium 1. Platinum bronze │ 1│ │ │ │ 90│ │Tin 9. Dentists’ alloy │ 5│ │ │ 3│ │ 4│ Dentists’ alloy │ 7│ │ 3│ 2│ │ │ Dentists’ alloy │ 6│ │ 1│ 2│ │ │ Dentists’ alloy │ │ │ │ 4│ │ 1│ Palladium alloy │ │ │ 2│ │ │ 3│ ───────────────────┴──────┴──────┴──────┴──────┴──────┴──────┴───────────── ALLOY SUBSTITUTES FOR PLATINUM On account of the scarcity and high price of the platinum metals, much attention has lately been directed towards the discovery of suitable substitutes. In the electrical industry an alloy of 3 parts of palladium and 2 parts of silver is in use, also an alloy of nickel and chromium. _Platinite_, an iron-nickel alloy, containing 46 per cent. nickel and 0·15 per cent. carbon, has the same coefficient of expansion as glass, and, when coated with copper, is used to replace the platinum connection wires of incandescent lamps. Tungsten is sometimes used for certain ignition devices. For cathodes an alloy of 90 per cent. gold and 10 per cent. copper can be used to replace platinum; the same alloy, if electrically coated with platinum, and then carefully polished and burnished, is suitable for platinum anodes.