Steve wrote:

"Ray" wrote in message
...
You know, the Chinese iron balls with the chimes inside like
http://www.uran.net/zlb/cloisonneexerciseballs.htm ?
Some are chrome plated and quite smooth. They've been around for hundreds
of years, though I don't know if they originally had the chimes inside.
I'd
hate to have to cut one open to find out!

--
Ray

From Google:

Virtually every sailing ship in the 1700-1800s had cannons for protection.
Cannons of the times required round iron cannonballs. The Ship's Master
usually wanted to store the cannonballs such that they could be of instant
use when needed, yet not roll around the gun deck. The solution was to stack
them up in a square-based pyramid next to the cannon. The top level of the
stack had one ball, the next level down had four, the next had nine, the
next had sixteen, and so on. Four levels would provide a stack of 30
cannonballs. The only real problem was how to keep the bottom level from
sliding out from under the weight of the higher levels. To do this, they
devised a small brass plate called, of course a brass monkey, with 16 round
indentations, one for each cannonball, in the bottom layer. Brass was used
because the cannonballs wouldn't rust to the brass monkey, but would rust to
an iron one. When temperature falls, brass contracts in size faster than
iron. As it got cold on the gun decks, the indentations in the brass monkey
would get smaller than the iron cannonballs they were holding. If the
temperature got cold enough, the bottom layer would pop out of the
indentations spilling the entire pyramid over the deck.

Thus it was, quite literally, "It Was Cold Enough to Freeze the Balls Off a
Brass Monkey!"

Now use Google to find the coeficient of expansion for brass and work
out just how much change in size there will be on that brass plate there
will be when going from plus 100 deg F to minus 35 deg F. Do same calcs
for iron (the cannonballs), as they will be subject to the same temp. as
the "monkey", contrary to the claim above.

Have fun....


Cheers
Trevor Jones