Saying

[Dukes01]

Where does the saying "Its cold enough to freeze the balls on a brass monkey" come from?

[Lord Unstone]

something to do with canon balls on ships. The monkey is the frame on which the balls are stored, it's made of brass. When these things got really cold, they contracted, and when the ship rolled, the balls fell off.

[Clanad]

Our somewhat pun uninteded but eponymous Lord Unstone has, unfortunately, succumbed to following the same rabbit trail left over from previous attempts to derive the origination of the phrase, resulting in yet another conglobated product... through no fault of his own.
While I usually abhor posting only links for answers, the following URL gives as indepth of an historical etymological examination of the phrase as I've seen:
http://www.phrases.org.uk/meanings/cold%20enou gh%20to%20freeze%20the%20balls%20off%20a%20bra ss%20monkey.html ... Best of Luck!

[mrs mop]

According to Susie Dent on Countdown Lord Unstone's answer is correct.

[Quizmonster]

Then Sisie Dent is wrong! Click here for what Michael Quinion - a real etymologist and lexicographer - has to say on the matter.

[johnny.5]

Outside pawn broker shop there used to be a brass monkey ( a brass sign with three brass balls dangling )
during cold spells icicles would form upon these balls and the added weight would cause them to fall . Hence cold enough to freeze the ball off a brass monkey



Am I right ?
I'm not wrong !

[Quizmonster]

Well, Michael Quinion certainly thinks you're wrong, Johnny! Do have a look at the web-page my link above takes you to. The man is a known language expert whose opinion actually matters, unlike virtually all the people such as Susie Dent with alternative ideas.
I can also add that The Oxford English Dictionary - regarded as the 'bible' in such matters - says nothing whatsoever about either cannons or pawnbrokers in this regard.

[Dukes01]

My understanding was that the phrase came into being from the Crimean war when England and Farnce fighting the Russians. (1854 - 56)
During the server Russian winter the cannon balls would freeze in their Brass Monkey casings. So I agree with Lord Unstone's summing up. Jonny.5 explanation sounds feasable however the saying is "On a brass Monkey" not "Off the brass monkey.

Maybe I'm wrong

[Quizmonster]

So, Dukes, what evidence do you have that such things as "brass monkey casings" for cannon-balls ever even existed, other than in phrase-books put together by people who clearly couldn't be bothered to do basic research and just repeated earlier errors?
And don't you think that - if they did exist - the scholars at The Oxford English Dictionary would have found the evidence? After all, that's what their job is...discovering the sources of words and phrases. They are recognised as the world's leading experts in doing precisely that.
Regarding Johnny's explanation, if you click here, you will find page after page of pictures of pawnbrokers' signs. I looked at the first ten pages - couldn't be bothered going any further - without seeing a single one with a monkey on it!
But what the hey! You're obviously free to believe whatever you wish.

[eastern]

Lord Unstone is right, nearly all slang expressions came from the navy, such as "show a leg" "3 square meals" "son of a gun" etc etc. There was a TV programme on one day about these expressions and the presenter walked around the ship quoting them all and there was dozens

[Quizmonster]

Ah, another member of CANOE! That's the Campaign to Ascribe Nautical Origins to Everything. A square meal, for example, had nothing to do with the British navy, but was originated by workmen and the hoteliers and restaurant-keepers who served them in America in the mid-19th century.
The point is that 'square' in this phrase had nothing whatsoever to do with tray-shapes, but was used in the sense of honest as in such sayings as, "I'll be square with you" or "fair and square". Thus, a square meal was simply a hearty one and good value for money.
I'm wasting my time here, I realise, but Michael Quinion - as referred to earlier - dismisses the navy connection with the words, "Rubbish, of course" which is much the same as he said about the brass monkeys.
Click here to see what he has to say about square meals. (The Oxford English Dictionary agrees with him on this one, too.)
However, if people insist on believing what amateur etymologisers say and won't accept the views of major language-experts in a matter concerning nothing but language, what more can one say? I suppose, when they're ill, they consult some guy sitting in the corner of the pub or when their car breaks down, they call in a joiner to fix it!

[Clanad]

Mama don't like it when you argue with the Q...