In the heyday of sailing ships, all war ships and many freighters carried iron cannons on board. Those cannons fired heavy iron cannonballs. It was necessary for each ship to keep a good supply of cannonballs near each cannon should they be attacked by a hostile vessel.
The problem each ship faced was how to prevent the round cannonballs from rolling around the deck. The solution was to stack the cannonballs in a square-based pyramid with one ball on top which would rest on four which would rest on nine, which would rest on sixteen. Thus, a supply of 29 cannonballs could be stacked in a small area right next to the cannon.
There was only one problem with this method - how do you prevent the bottom layer from sliding or rolling about from under the others? The solution was the invention of a metal plate called a "Monkey" with 16 round indentations. However, if this plate were made of iron, the iron balls resting in the indentations would quickly rust with the salt water spray. So to prevent the rusting problem, "Brass Monkeys" were developed.
Therefore whenever the outside temperature fell to around 32 degrees, it was quite literally "cold enough to freeze the balls off a brass monkey."
Hope you enjoyed this brief history lesson. Remember learning can and should be fun . That's the reason so many professional associations, business organizations and units of local government invite Gabe Gabrielsen to solve their problems and provide their employees and staffs with great educational programs.