"Cold enough to freeze the balls off a brass monkey"

Posted by Alastair on June 07, 2004

I believe this originates from Steam Trains. The 'Brass Monkey' is the steam safety valve - consisting of 2 brass balls attached to levers. The balls spin round - if they spin fast enough, it opens the steam valve.

• "Cold enough to freeze the balls off a brass monkey" Li Yar 07/June/04