PEWTER, PEWTERER. Pewter is, generally speaking, an alloy of tin and lead, sometimes with a little antimony or copper, combined in several different pro portions, according to the purposes which the metal is to serve. Plate pewter has a bright silvery lustre when polished ; the best is composed of 100 parts of tin, 8 parts of antimony, 2 parts of bismuth, and 2 of copper. The trifle is said by some to consist of 83 of tin, and 17 of an timony; but it generally contains a good deal of lead. The ley pewter is composed of 4 of tiu, and 1 of lead. As the tenden cy of the covetous pewterer is alwayi to put in as much of the cheap metal as is compatible with the appearance of his metal in the market, and as an excess of lead may cause it to act poisonously upon all vinegars and many wines, the French government long ago appointed Foureroy, Vauquelin, and other chemists, to ascer tain by experiment the proper proportions of a safe pewter alloy. These commis sioners found that 18 parts of lead might, without danger of affecting wines, &c., be alloyed with 82 parts of tin ; and the French government in consequence pass ed a law requiring pewterers to use 83# of tin in 100 parts, with a tolerance of er ror amounting to 11 per cent. This or donnance, allowing not more than 18 per cent. of lead at a maximum, has been ex tended to all vessels destined to contain alimentary substances. A table of speci
fic gravities was also published, on pur pose to test the quality of the alloy ; the density of which, at the legal standard, is 7-764. Any excess of lead is immediately indicated by an increase in the specific gravity above that number.
The pewterer fashions almost all his ar ticles by casting them in moulds of brass or bronze, which are made both inside and outside in various pieces, nicely fit ted together, and locked in their positions ly ears and catches or pins of various kinds. The moulds must be moderately heated before the pewter is poured into them, and their surfaces should be brush ed evenly over with pounce powder (san darach) beaten up with white of egg. Sometimes a film of oil is preferred. The pieces, after being east, are turned and polished ; and if any part needs soldering, it must be done with a fusible alloy of tin, bismuth, and lead.
Britannia metal, the kind of pewter of which English tea-pots are made, is said to be an alloy of equal parts of brass, tin, antimony, and bismuth ; but the propor tions differ in different workshops, and much more tin is commonly introduced. Queen's metal is said to consist of 9 parts of tin, 1 of antimony, 1 of bismuth, and 1 of lead ; it serves also for tea-pots and other domestic utensils.