A reference to extreme cold. According to the
United States Navy Historical Center, this is a legend of the sea without historical justification. The center has researched this because of the questions it gets and says the term βbrass monkeyβ and a vulgar reference to the effect of cold on the monkeyβs extremities, appears to have originated
in the book βBefore the Mastβ by C.A. Abbey published in 1857. It was said that it was so cold that it would βfreeze the tail off a brass monkey.β. The Navy says
there is no evidence that the phrase had anything to do with ships or ships with cannon balls.