What is the origin of the term 'brass monkey'?

The story goes that cannonballs used to be stored aboard ship in piles, on a brass frame or tray called a 'monkey'. In very cold weather the brass would contract, spilling the cannonballs: hence very cold weather is 'cold enough to freeze the balls off a brass monkey'. There are several problems with this story, as follows:

• the term 'monkey' is not otherwise recorded as the name for such an object
• the rate of contraction of brass in cold temperatures is unlikely to be fast enough to cause the reputed effect
• the phrase is actually first recorded as 'freeze the tail off a brass monkey', which removes any essential connection with balls.

It therefore seems most likely that the phrase is simply a humorous reference to the fact that metal figures will become very cold to the touch in cold weather.

 

Take a look at: The origin of the word 'penguin'.

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