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

Where did the term brass balls come from