It can't be denied that this is an ingenious and entertaining
suggestion, but, like much 'folk etymology', it is almost certainly
wrong, even though at least one other source -- the usually reliable
_Dictionary of Word and Phrase Origins_ by Nigel Rees -- echoes it
almost verbatim.
Be that as it may, recourse to a number of dictionaries, from the
comprehensive and authoritative _Oxford English Dictionary_ (OED) to
such period and specialist works as Francis Grose's _Dictionary of the
Vulgar Tongue_ (1796), Falconer's _Marine Dictionary_ (1815), and, of
course, that great lexicographic well-spring, Johnson's _Dictionary_
(1755), yields up no mention of 'monkey' used in the sense suggested.
The word does not, of course, lack nautical associations: it is (or
was) used as a diminutive modifier, describing things which were small
or short (e.g., 'monkey block', 'monkey jacket'), and it identified a
type of reciprocating steam engine. It was also one of the many names
given the wooden kid (or, later, brass kettle) in which the rum ration
for a mess was issued.*
It figures, too, in early artilleryman's jargon: small 'brass'
(actually bronze) guns, otherwise christened 'dogs' or 'drakes', were
identified as 'monkeys' in several 17th century inventories.
But the word has never, it seems, described a shot rack of any kind.
Such devices were, in any case, unknown until the 18th century, when
perforated planks were used to store ranked -- but not stacked -- shot
ready to hand along the gun deck ceiling between gunports, and, later
(after 1780), around the hatchways. Wherever these shot racks were
located, however, they were universally known as 'shot garlands'.
(See Brian Lavery's _The Arming and Fitting of English Ships of War,
1600-1815_.)
Shot was never stacked on board warships under way, of course, unless
it was first secured by a tarpaulin cover. The ship's motion, even in
a moderate seaway, would soon have sent loose, stacked shot rolling
wildly across the decks.
So, how did 'cold enough to freeze the balls off a brass monkey'
originate? I'm damned if I know. I can guess -- anyone can play at
the game of folk etymology -- but my guess is just that; it's
unsupported by any authority. Monkey was once used as a 'term of
playful contempt' (OED), chiefly in describing young people. 'Brass'
can refer to effrontery or impudence. A young man, who brazenly
defied his elders to venture out in search of pleasure on a brutally
cold day, and who suffered frost-bite or worse in consequence, might
well, I suppose, have been met on his return with something along the
lines of, 'I told ye, lad, that it war cold enough to freeze the balls
right off any monkey like you with the brass to go out about sich
silliness in this weather.' It would then only be a short step to
'cold enough to freexe the balls off a brass monkey'.
Enough. With temperatures in the teens, it's almost beach party
weather in the northern marches of New York. Late February -- now
that's another story. Forty below zero and falling fast. Damned if
it won't be cold enough to freeze the balls off a whole battalion of
brass monkeys then!
Forrest Brownell
South Colton NY
* My favourite name for this vital vessel is 'fanny', supposedly
derived from Fanny Adams, an unfortunate young woman whose
dismembered body was found in the Deptford victualling yard just as
experiments with tinned, preserved mutton were being conducted.
When emptied of their dubious contents, the Deptford mutton tins
were subsequently pressed into service to hold rum for each mess
aboard the ships of the Royal Navy. In recognition of the
inadvertent service which young Fanny may well have rendered in
victualling the fleet, the tins were christened in her honour. Or
so the story goes; you can find it in _Nelson's Blood: The Story of
Naval Rum_, by Captain James Pack OBE RN. Given the other,
well-established, meaning of Fanny Adams, however, you'd be right to
be a bit sceptical, I think.