Cold enough to freeze the balls off a brass monkey : Phrases
I am not going outside. It is cold enough to freeze the balls off a brass monkey and mine are considerable more sensitive.
In the 1700s cannon balls and black powder were carried by boys referred to as powder monkeys.
One explanation has it that the balls were stacked in the familiar pyramid configuration with a wooden triangle holding the bottom layer together. These wooden triangles (perhaps as an extension of powder monkey) were also referred to as monkeys. The trouble with wooden monkeys was that they couldn't take much abuse before shattering under the impact of dropped cannon balls.
The next material used to make monkeys was brass. These worked perfectly in warmer weather. The trouble with brass monkeys was that they tended to shrink a little when the weather turned cold enough. This shrinkage squeezed the bottom layer up, sending balls rolling all over the deck.
Interesting tale, but not likely. The boys were definitely called powder monkeys, and the triangles may indeed have been called monkeys. But the idea that cold weather would cause enough shrinkage to squeeze out the cannon balls is fanciful. Brass is an alloy made of copper and nickel and is quite stable.
Considering the size of even a small cannon ball is perhaps 2 to 3 inches in diameter, the amount of shrinkage of the monkey would have to be a couple of inches to push out the balls. Impossible.
Alternative: On war ships, it was necessary to keep a good supply of canon balls near the cannon. 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.