Good knowledge in these cold times

In the good old days?, it was necessary to keep a good supply of canon
balls near the cannon on 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 was 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?

You must send this fabulous bit of historical knowledge to unsuspecting
friends. If you don't, your hard drive is going to fall off and kill your
mouse.