m 
Brass* 
about one-fifth of the whole, forms an alloy which is the 
principal, and often the only composition for bells, brass 
cannon (so called) bronze statues, and several smaller pur® 
poses, and hence it is called Bronze , or Bell-Metal (always 
observing that there is no perfect uniformity in the differ- 
ent alloys under these names, either in the proportion or 
the actual number of ingredients) and it is excellently fit® 
ted for these purposes, by its hardness, density, sonorous® 
ness, and fusibility, whereby the minute parts of hollow 
moulds may be readily filled before it fixes in cooling. 
For cannon, a lower portion of tin seems to be used. 
According to Dr. Watson, the metal used at Woolwich 
is 100 parts of copper and 8 to 12 of tin. Hence it still 
retains some little malleability, and of course is tougher 
than with more tin. Bronze cannon are much less liable 
to rust than those of iron, but in large pieces of ordnance, 
by very rapid firing the touch-hole is apt to melt down 
and spoil the piece ; of which there is a remarkable in- 
stance at the Tower of London of a mortar of the largest 
calibre thus spoilt at the siege of Namur. On account 
<of the sonorousness of bronze, these cannon give a much 
sharper report than those of iron, which for a time impairs 
the hearing of the people that work them. A common 
alloy for bell metal is about 80 of copper to 20 of tin ; or 
where copper, brass, and tin are used, the copper is from 
70 to 80 per cent, including the portion contained in the 
brass, and the remainder is tin and zinc. The zinc cer- 
tainly makes it more sonorous. Antimony is also often 
found in small quantity in bell-metaL Some of the finer 
kinds used for small articles contain also a little silver, 
which much improves the sound. 
When the tin is nearly one-third of the alloy it is then 
most beautifully white, with a lustre almost like that of 
mercury, extremely hard, very close-grained, and perfect® 
ly brittle. In this state it takes a most beautiful polish*- 
