BRASS MONKEY - term origin

Posted by Bruce Clark on January 31, 2002

Can someone please tell me the origin of the term 'brass monkey'.

A 'brass monkey' is the term for the base for stacking cannon balls in pyramid shaped stacks onboard old sailing war ships. The base (brass monkey) was made of brass with indentations the size of the cannon balls. It prevented the cannon balls from rolling around when stacked.

Question: why is this base for stacking cannon balls called a 'brass monkey'?