Brass Monkey


Mar 3, 2008
In the heyday of sailing ships, all war ships and many freighters
carried iron cannons. Those cannons fired round iron cannon balls.
It was necessary to keep a good supply near the cannon, but how to
prevent them from rolling about the deck? The best storage method
devised was 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 or rolling from under the others. The solution
was a metal plate called a "Monkey" with 16 round indentations.
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 an improper
expression, didn't you?)