These are employed fur making metallic reflectors, requiring a true white colour, good lustre, and a hard, clean surface not easily tarnished or scratched. Fesquet gives a number of combinations, as follows:-

(a) 62 parts copper, 32 tin, 6 lead; (6) 80 copper, 10 lead, 10 antimony; (c) 66 to 63 copper, 33 to 27 tin; (d) 10 copper, 10 tin, 10 antimony, 50 lead; (e) 32 copper, 50 tin, 1 silver, 1 arsenic; if) 90 steel, 10 nickel; (g) 50 palladium, 50 silver; (A) 60 platinum, 40 copper; (i) 50 platinum, 50 steel; (j) 50 platinum, 50 iron; (k) 10 platinum, 90 steel; (I) 20 platinum, 80 copper, 0.5 to 1 arsenic; (m) 60 platinum, 30 iron, 10 gold; (n) 50 gold, 50 zinc; (o) 50 steel, 50 rhodium; (p) 10 platinum, 90 iridium; (7) 29 tin, 19 lead; (r) 52 copper, 30 nickel, 12 zinc, 5 lead, 1 bismuth.