This piece of random sh*t and alleged history explains that in the olden days of sailing ships, cannon balls were stacked on the decks on brass plates called "monkeys." The plates had indentions in them that held the balls on the bottoms of the stacks. Brass, however, expands and contracts with the temperature and if it got cold enough, the cannonballs could fall...giving real foundation to the phrase "cold enough to freeze the balls off a brass monkey!"