348 On the Manufacture of Tin-plate. 
is found to impart great hardness to the tin, 
without Jessening its ductility. 
The combination of mercury and tin, in 
which the tin is dissolved by the mercury into 
a very soft amalgam, is largely employed, 
as is well known, in silvering the backs of 
mirrors, and for other purposes in the arts. 
‘An amalgam of tin. of greater consistence 
was formerly in use in the museums of Paris 
for closing the mouths of glass-bottles con- 
taining sundry curious and valuable prepa- 
rations. | 
Copper is also alloyed with tin for various 
purposes of manufacture. This metallic mix- 
ture is employed in making what are called 
bronze ‘statues ; for casting bells, and pieces 
of artillery, and also for the fabrication of 
medals and medallions. In some of these 
cases the tin is mixed with copper, on ac- 
count’of its property of rendering the’cop-. 
per more fusible; and this was probably the 
reason why the ancient Romans used that 
metal in the greater part of their brass coin- 
age. It is owing to the affinity of tin for 
copper, that vessels of capacity, made with 
the latter metal, for culinary and other pur- 
poses, are so readily covered with a coating 
of tin, to preserve them from the aétion’ of 
substances which. would not fail to erode 
