Percussive Etymology – Cold enough to freeze something off a brass monkey

It’s time for the second instalment of Percussive Etymology. In this fortnightly feature my trusty hammer and I will explore the origins of one of the many quirky phrases contained in the English language.

Percussive EtymologyAfter the resounding success of my post on “gumming up the works” it’s a bit intimidating to write another one of these. What if people don’t like it as much? What if I get no comments at all? What if I unwittingly offend my readers and they all unfollow this blog at once? (Do bestselling authors live with this pressure each time they submit a new novel to their publishers?)

However, let no man person call me a coward. Today’s phrase (and pardon the French), “Cold enough to freeze the balls off a brass monkey”. Thanks to Matthew Wright for the suggestion.

(By the way, the best part of today’s post is at the very end, below the line.)

Cold enough to freeze the balls off a brass monkey

An important part of educating people is helping them to unlearn incorrect data before teaching them the correct facts, and there is a popular fallacy connected to this phrase. In the popular theory, the “brass monkey” refers to a brass frame that was used on the decks of sailing ships to stack cannonballs in pretty little pyramids for easy access. In very cold weather the frame would shrink, causing the cannonballs to fall off.

I did extensive research on this and found that it’s complete nonsense. Cannonballs were not stacked on the decks of ships. First, salt water rusts iron and a rusted cannonball could get stuck in the cannon and blow it up. Second, stacking round cannonballs on the constantly pitching deck of a ship with hundreds of sailors running around is just asking for someone to get hurt.

Besides, if you take into consideration the coefficient of expansion of brass and iron, a one millimetre shrinkage of the brass frame relative to the iron cannonballs would require a 100 degrees (Celsius) drop in temperature. You’d need much more shrinkage than one millimetre to topple a stack of cannonballs.  “Brass monkey” in isolation does appear to be a term used for cannons at some point, but cannonballs do not come into it.

Some more digging revealed that the phrase did not originally refer to the monkey’s…erm…family jewels, but used to be “cold enough to freeze the tail off a brass monkey”. This phrase originated in Indonesia. Monkeys are considered sacred there, and there used to be brass monkey statues guarding temples and the entrances to the sacred monkey forest in Bali.

One year, around the turn of the nineteenth century, South East Asia suffered a severe drop in temperature, akin to the polar vortex that struck North America and Europe earlier this year. The rain forests were covered in snow and the temperature fell so low that the metal of the brass monkeys actually became brittle, causing some of them to break at the weakest part – just below where the tail is attached to the body. British naval officers stationed there at the time remarked on this in their journals and letters home, and the phrase became part of the common lexicon.

But what about the monkey’s marbles? Turns out this version of the phrase comes from the oral history of Tibet. There used to be a village in a valley high in the Himalayas during the Ming dynasty in China (or it could have been the Ching dynasty…something ending in -ing).

This village was under constant threat of avalanches, until a local inventor and sculptor came up with a solution. Towers were built on the surrounding slopes. Inside each tower was a large bell. Also inside each tower was a brass monkey, positioned above the bell. Why a monkey? Your guess is as good as mine.

Anyhow, the monkeys were cast hollow and a number of solid steel balls were placed in each via a hole in the bottom. The hole was plugged with an unknown alloy, the expansion coefficient being such that at a certain temperature the plug would fall out of the hole releasing the balls. They would then fall onto the bell, the resonance of which would trigger a localised avalanche and preventing a more catastrophic event.

It worked like a charm, and also became a prime example of the law of unintended consequences at work: One particularly cold night all the monkeys released their balls at once, the resulting gongs triggering a cascade of avalanches and rockfalls which completely covered the village. No one survived. Which does beg the question how this legend made it into the oral history of Tibet. That’s history for you. Completely unpredictable.


While most of this is made up (so please don’t quote me in your dissertation), there really was no such thing as a brass monkey used on ships to stack cannonballs (at least not according to any written records). Cannonballs were stored below-decks in planks with circular holes cut in them called shot garlands.

The last part also is partially based in fact: on 6 January 1987 US patent 4634021 was issued to one John W. Davis for a, well, a brass monkey (if you click the link you can see a picture) that loses its balls when it gets too cold, proving once again, that truth is often much, much stranger than fiction.

If you have a phrase or expression you want me to use for a future edition of Percussive Etymology, tell me in the comments.  If you know the real etymology of the phrase “cold enough to freeze the whatever off a brass monkey”, please share.

Image courtesy of The Wife.

14 thoughts on “Percussive Etymology – Cold enough to freeze something off a brass monkey

  1. Thank you for the shout-out…a great post & a wonderful story! This has to be one of my favourite ‘mystery phrases’ because the actual explanation for it is so completely lost. Nautically speaking, as you point out, shot garlands were never called a ‘brass monkey’. I believe the officer uniform jacket of the late nineteenth and early twentieth centuries was nicknamed a ‘monkey jacket’; and in the fifteenth century, some ships carried a type of cannon known as a ‘monkey’. But how any of that might have transmuted to ‘freeze the balls of a brass monkey’? Dunno. Maybe the derivation isn’t nautical.

    1. I also read that the cannoneers were referred to as ‘powder monkeys’ at some stage, but that’s as close as I got.

      Would you believe I only read about that patent after I’d already written this? I kinda wonder if that guy ever made any money from his idea.

    1. I didn’t realise that one was a myth. Hi-ho, hi-ho, and off to Snopes we go…

      Of course, as all this is completely made up you’re only going to end up with an even worse myth, but thanks for the suggestion. I’ve been thinking that expression could also make a good one 😀

      I was interested to note the both the entries for “brass monkey” on Urban Dictionary perpetuated the cannonball-holder idea and Zemanta suggested several blog posts that stated the same as fact. I’m starting to think first exposing the popular fallacies around an expression before making up my own could well be a worthwhile exercise.

      1. The phrase actual comes from the habit of carpenters using their thumbs as a ruler–hence “rule of thumb” meaning something that may not be entirely accurate, but is close enough for an approximation.

  2. Wonderful, my finger didn’t even hover anywhere near the ‘Unfollow’ button.

    When I was reading the South East Asian part of the story, my mind was filling in the blanks – like stepping stones – and what came to mind to explain the drop in temperature was Krakatoa.

    What is the dictionary reading?

    1. Hmmm. I haven’t thought about what the dictionary is reading. Probably a Mathematics textbook, cause everyone needs a distraction 😀

      I didn’t know about Krakatoa. That would cause some cold weather, the ash blocking out the sun for weeks… I don’t get the stepping stones reference. Care to enlighten me?

      1. Reading a maths book – of course. 🙂

        The ‘stepping stones’ are what I call the seemingly logical steps I take to arrive at a sensible and meaningful conclusion in the face of overwhelming evidence otherwise. An example would be where I am reading two novels at the same time and pick up one thinking it is the other. I read for a few paragraphs and my mind ‘shoves’ the plot to make sense in the book I think I am reading.

        I think jokes rely upon stepping stones that take a sudden turn sideways while the listener’s foot is already poised over where the listener thinks the next stepping stone is going to be.

      2. It’s amazing the way the mind works with stuff like this. “Stepping stones” is a nice analogy.

        At college a bunch of us used to play a game where one would make a cause-effect statement with no logical link between the cause and the effect. The other then had to fill in the blanks to connect the two. Same concept, I think.

        (I’m glad to hear I’m not the only one who reads two novels at once, though I haven’t done that in a while.)

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