TIN 
acid, and some sulphur, are disengaged, and 
there remains in the vessel a compound of 
a brilliant, golden colour. It crystallizes 
in six-sided plates. It is not acted on by 
the acids. When it is strongly heated, it 
gives out sulphuri^us acid and sulphur, and 
there remains behind a black mass, which 
is sulphuret of tin. This compound, which is 
a sulphurated oxide of tin, was formerly 
distinguished by the. name of aurura, musi- 
vum, musicura, or raosaicum. The compo- 
nent parts of this sulphurated oxide of tin 
are 
Oxide of tin 60 
Sulphur ‘^0 
ioo 
Tin enters into combination with many 
of the metals, and forms alloys with them, 
some of which are of great importance. • It 
also combines with acids, and forms salts. 
Of the alloys, the most important is that 
of tin and copper, with some other addi- 
tions, which forms bronze, bell-metal, spe- 
culum, metal, &c. The alloy of tin and 
lead, in equal parts, forms plumbers’ solder. 
The alloy of tin, lead, and bismuth, in the 
proportions of 3, .S, and 8, forms a com- 
pound that melts in a heat somewhat less 
than that of boiling water. The amalgam 
of mercury with tin is used in silvering of 
mirrors. Pewter is an alloy of tin and lead, 
which was formerly very much used, more 
so than any other metallic alloy, being the 
common material for plates, dishes, and 
other domestic utensils. Its use now is 
most universally superseded by pottery, 
which is lighter, more readily kept clean, 
and much cheaper, though certainly less 
durable, on account of the brttCzuess of 
the latter. The name of pewtor has been 
given to any malleable while alloy, into 
which tin largely enters, and iCa composi- 
tion is so various, that Imrdly any two ma- 
nufacturers employ precisely the same in- 
gredients, and Ae same proportions. The 
finest kind of pewter contains no lead what- 
ever, but consists of tin with a small alloy 
of antimony, and sometimes a little copper; 
and in all the superior kinds of pewter, the 
tin forms by far the greater part of the 
mixture. Pewter may be used for vessels 
containing wine, and even vinegar, provided 
there be from 80 to 82 parts of tin in the 
alloy, without the smallest danger ; hence its 
use as a measure. The specific gravity of 
a mixture of tin and lead is less than the 
mean specific gravity of the two metals se- 
parately. 
TIP 
Tin is much used, particularly in the 
state of very thin leaves : it is then called 
tin-foil. This is made from the finest tin, 
first cast into an ingot, then laminated to a 
certain extent, and afterwards beat out 
with a hammer. Tin is used for tinning 
copper, iron, &c. and the salts of tin are 
employed in dyeing. 
Tin plate, tinning. Tin combines with 
iron, md adheres strongly to its surface, 
forming a thin covering. This is one of the 
most useful combinations of tin, for it ren- 
ders the iron fihfor a great many valuable 
purposes, for which, otherwise, on account 
of its strong tendency to oxidation, or 
rusting, it would be totally inapplicable. 
This is well known by the name of tin- 
plate, or white iron. 'The process of tin- 
ning iron is the following : the plates of iron 
being reduced to the proper thickness, are 
cleaned by means of a weak acid. For this 
purpose the surface is first cleaned with 
sand, to remove any rust that may have 
formed. They are then immersed in wa- 
ter, acidulated with a small quantity of sul- 
phuric acid, in which they are kept for 
twenty-foiu- hours, and occasionally agi- 
tated. They are then well rubbed with 
cloths, that the surface may be perfectly 
clean. The tin is fused in a pot, the sur- 
face of which is covered with an oily or re- 
sinous matter, to prevent its oxidation. 
The plates of iron are then immersed in 
the melted tin, and are either moved about 
in the liquid metal, or are dipped several 
different times. They are then taken out, 
and rubbed with saw-dust or bran, to re- 
move the impurities from the surface. 
TINCTURE, is commonly understood 
to be a coloured infusion of any substance 
in alcohol. It is a preparation much em- 
ployed in Pharmacy, with many articles 
of the Materia medica (which see), parti- 
cularly vegetable barks, aromatics of all 
kinds, and many of the resins and gum 
resins, which yield to alcohol, by infusion, 
that part of their substance in which most 
of the medicinal virtue resides. 
Tincture, in heraldry, the hue or co^ 
lour of any thing in coat armour, under 
which denomination may also be included 
the two metals, or and argent, because they 
are often represented by yellow and white. 
TIPHIA, in natural history, a genus of 
insects of the order Hyraenoptera. Mouth 
with a membranaceous rounded jaw, the 
mandible arched and acute ; no tongue ; 
four feelers, filiform, unequal, and inserted 
in the middle of the lip ; antennae filiform ; 
