Green’s Dictionary of Slang

a hot drink made of ale and brandy boiled together.

1698		M. Sorbiere Journey to London in the Year 1698 p.35, cited in N&Q Ser. 6 XII (1885) 167: He answer’d me that he had a thousand such sort of liquors, as Humptie Dumtie, Three Threads, Four Threads, Old Pharaoh, Knockdown.
1725		New Canting Dict. n.p.: Humptey-dumptey Ale boild with Brandy.
1732		Delightful Adventures of Honest John Cole 16: Cole thought it was time to go to Breakfast, and treated his Master with black Jack full of Humty Dumty.
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict. [as cit. 1725].
c.1750–1882		B.M. Carew Life and Adventures.
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue.
1809		G. Andrewes Dict. Sl. and Cant.
1811		Lex. Balatronicum.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.
1837		‘The Cannon Family’ in Bentley’s Misc. Nov. 456: Over a bowl of generous humpty-dumpty, Sam was prevailed upon to take charge of a small parcel of little articles.
1848		Flash Dict. in Sinks of London Laid Open.
1940		Chelmsford Chron. 26 Jan. 5/4: Old English drinks [...] Humpty-Dumpty, Hugmatee [...] Knock-Me-Down.