Green’s Dictionary of Slang

cat n.4

[a double-kitten n. (1)]

a quart pot.

implied in cat and kitten rig
[US]Matsell Vocabulum 18: cat. [...] a pewter pot.
[UK]Peeping Tom (London) 32 128/2: [G]entlemen engaged in [...] picking up a cat and her kittens — the cat being a quart pot and the kittens pints!
[UK](con. 1840s–50s) H. Mayhew London Labour and London Poor I 414/1: At this lodging-house cats and kittens are melted down, sometimes twenty a day. A quart pot is a cat, and pints and half pints are kittens.

In compounds

cat and kitten hunter (n.) (also cat and kitten stealer)

(UK Und.) a person who steals pewter quart and pint pots from public houses.

[UK]H. Mayhew Great World of London I 46: ‘Cat and Kitten Hunters,’ who make off with quart and pint pots from area railings.
[UK]H. Mayhew London Labour and London Poor IV 26: [as cit. 1856].
[Aus]Argus (Melbourne) 20 Sept. 6/4: Amongst these small fry of the profession [are] the carrier pigeon, a swindler’s agent, the cat and kitten stealer, whose special line is quart and pint pots, the Charley pilcher [sic], a very poor kind of cheat, the dido, who steals from carts.
cat and kitten hunting (n.) (also cat and kitten sneaking, ...stealing)

(UK Und.) the stealing of pint and quart pots from public houses.

[UK]‘Adventures of Mr and Mrs Sandboys’ in Bells New Wkly Messenger 9 Mar. 6/2: I may mention [...] bluey-hunting, or pilfering metal and especially lead from the tops of houses; and cat and kitten hunting, or abstracting pewter quart and pint-pots.
[UK]‘Ducange Anglicus’ Vulgar Tongue 7: Cat and Kitten Hunting Stealing publicans’ pewter pots.
[[UK]A. Mayhew Paved with Gold 268: He could tell tales of trunks knowingly cut away from their lashings to the hind springs, or how he had ‘pricked for panam in the wicker,’ or ‘sneaked a cat and kitten’ from the tap-room].
[UK]Hotten Dict. of Modern Sl. etc. 18: CAT AND KITTEN SNEAKING, stealing pint and quart pots from public-houses.
[UK]Hotten Sl. Dict. [as cit. 1859].
[Aus]Crowe Aus. Sl. Dict. 15: Cat and Kitten Stealing, stealing quarts and pints from hotels.