"00 TINNING COPPER, &C. 



been esteemed unwholesome, notwithstanding it contains near one- 

 twelfth of its weight of copper. Though standard silver has al- 

 ways been considered as a safe metal, whtn used for culinary pur. 

 poses ; yet it is not altogether so, the copper it contains is liable 

 to be corroded by saline substances into verdigris. This is fre- 

 quently seen, when common salt is sufk-red to stay a few days in 

 silver saltcellars, which have not a gold gilding; and even saline 

 draughts, made with volatile salt and juice of lemons, hare been 

 observed to corrode a silver tea-spoon, which had been left a week 

 in the mixture. 



The weight of a cubic foot of each of these sorts of pewter is, 



Plate 7248 



Trifle 7359 



Ley 7963 



If the plate pewter be composed of tin and regulus of antimony, 

 there is no reason to expect, that a cubic foot of it should be hea- 

 vier than it appears to be ; since regulus of antimony, according 

 to the different ways in which it is made, is heavier or lighter than 

 pure tin. A very fine silver-looking metal is said to be composed 

 of 100 pounds of tin, 8 of regulus of antimony, 1 of bismuth, and 

 4 of copper. The ley pewter, if we may judge of its composition 

 by comparing its weight with the weights of the mixtures of tin 

 and lead, mentioned in the table, contains not so much as a third, 

 but more than a fifth part of its weight of lead ; this quantity of 

 lead is far too much, considering one of the uses to which this sort 

 of pewter is 1 applied ; for acid wines will readily corrode the lead 

 of the flagons, in which they are measured, into sugar of lead ; this 

 danger is not so great with us, where wine is seldom fold by the 

 measure, as it is in other countries where it is generally sold so, 

 and their wine measures contain, probably, more lead than ours 

 do. Our English prwterers have at all times made a mystery of 

 their art ; and their raufion was formerly so much encouraged by 

 the legislature, that an act of parliament was passed, rendering it 

 unlawful for any master pewterer io fake an apprentice, or to em. 

 ploy a journeyman, who was a foreigner. In the pn-Miit improved 

 >i (li'in'st'\, i!: : s r.'u"!>M is useless ; since any one tolerably 

 skii.ed in (hat scimce, would be able to discover the quality and 

 quantity of the metallic cci in any particular sort of 



pewter ; and it is not only useless now, but one would have thought 

 it must have been always so; whilst tin, the principal ingredient, 



