Tin, 
367 
substance, may be taken inwardly with great safety ; but 
the metallic part, or rcgulus , when separated from the sul- 
phur, is held to be very poisonous. Yet plate pewter 
may be a very innocent metal, the tin may lessen or anni- 
hilate the noxious qualities of the metallic part of the anti- 
mony. We have an instance somewhat similar to this in 
standard silver, the use of which has never been esteemed 
unwholesome, notwithstanding it contains near one 
twelfth of its weight of copper. Though standard silver 
has always been considered as a safe metal, when used for 
culinary purposes ; yet it is not altogether so, the copper 
it contains is liable to be corroded by saline substances in- 
to verdigris. This is frequently seen, when common 
salt is suffered to stay a few days in silver salt-cellars, 
which have not a gold gilding ; and even saline draughts, 
made with volatile salt and juice of lemons, have 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 regains of 
antimony, there is no reason to expect, that a cubic foot 
of it should be heavier than it appears to be ; since rcgu- 
lus 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 ICO pounds 
of tin, 8 of regulus of antimony, 1 of bismuth, and 4 of 
copper. The ley pewter, if we may judge of its compo- 
sition 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. 
