(The Phrase Finder): “The earliest example of *it in print that I can find is a definition of the term in the weekly literary review The Athenaeum 1919:
“The expression ‘Put a sock in it’, meaning ‘Leave off talking, singing or shouting’.”
The fact that an erudite publication saw fit to define the term suggests it was recently coined in 1919.”
“Old Slaughter’s Coffee House was a coffee house in St Martin’s Lane in London.
It was opened in 1692 by Thomas Slaughter and so was first known as Slaughter’s or The Coffee-house on the Pavement, as not all London streets were paved at that time. It was at numbers 74–75 but, around 1760 after the original landlord had died, a rival New Slaughter’s opened at number 82 and the first establishment then became known as Old Slaughter’s.
It was patronised by players of games including chess, draughts and whist. Notable players included Abraham de Moivre, Benjamin Franklin and Philidor. It was also popular with artists of all kinds – architects, painters, poets, sculptors, &c. This artistic community included Dryden, Gainsborough, Hogarth, and Roubiliac. Foreigners such as Frenchmen were often there and Boswell reports Dr Johnson’s comment on this around 1780:
His unjust contempt for foreigners was, indeed, extreme. One evening, at Old Slaughter’s Coffee-house, when a number of them were talking loud about little matters, he said ‘Does not this confirm old Meynell’s observation, For any thing I see, foreigners are fools?’
— James Boswell, The Life of Samuel Johnson, LL. D.
Henry Fielding was a regular and nicknamed the head-waiter “Sock”. Sock was said to be the out-of-wedlock son of the popular comedian, James Spiller, and had a similar talent for droll wit. On one occasion, he partook of a customer’s punch while bringing it and excused this by saying that he had spilled it. Thereafter, Sock was also known as the “Punch Spiller”.
It was used as a meeting house and the Society for the Prevention of Cruelty to Animals, which subsequently became the RSPCA, was founded there in 1824. The meeting was organised by the Reverend Arthur Broome and chaired by Sir Fowell Buxton. There were eight other gentlemen attending including “Humanity Dick” – Colonel Richard Martin – who had successfully campaigned for the Cruel Treatment of Cattle Act in 1822 but whose latest bill for the Prevention of Cruelty to Animals, had been defeated in the Lords that day. Other MPs attending included Sir James Mackintosh and William Wilberforce.
The premises were demolished in the winter of 1843 when Cranbourn Street was constructed.”