>Another from my mom:
>
>
>Cannon Balls
>
> In olden times it was necessary to keep a good supply of cannon balls near the
>cannon on old war ships.
>
> But how to prevent them from rolling about the deck was the problem. The best
> storage method devised was to stack them as a square based pyramid with one
> ball on top resting on four resting on nine which rested on sixteen. Thus a
> supply of 30 cannon balls could be stacked in a small area right next to the
> cannon.
>
> There was only one problem -- how to prevent the bottom layer from
> sliding/rolling from under the others. The solution was a metal plate with 16
> round indentations called a Monkey. But if this plate were made of iron the
> iron balls would quickly rust to it. The solution to the rusting problem was
> to make Brass Monkeys.
> Few landlubbers realize that brass contracts much more and much faster than
> iron when chilled. Consequently when the temperature dropped too far the brass
> indentations would shrink so much that the iron cannon balls would come right
> off the monkey. Thus it was quite literally cold enough to freeze the balls
> off a brass monkey.
> And all this time you thought that was a vulgar expression
> didn't you?
>
>

No. I thought everyone knew this and I couldn't count the number of times I've heard that explained :-)