The very first line of nineteen eighty four is "It was a bright cold day in April, and the clocks were striking thirteen." The book begins on this absurd note. Clocks do not strike thirteen anymore than ,well, two plus two equals five. True there is military time but I don't think that was what Orwell was trying to convey. His intention was something more poetic. He is suggesting that something is wrong, something absurd about the world we are entering. I don't think "the clock striking thirteen" is common enough to be considered an idiom. In addition to "Nineteen eighty four" shows up in only a few other places notably in A.P. Herbert's "Uncommon Law", a collection of fictional legal cases which were original published in the British satirical magazine “Punch”. The fictious case in question is “Rex vs. Haddock” subtitled “Is it a Free Country?” the full text of which can be found here. https://www.scribd.com/document/12...