Green’s Dictionary of Slang

1. (UK Und., also jacken closer, jarke, jasker, jerke, jurk) a seal.

c.1561		Awdeley Fraternitye of Vacabondes in Viles & Furnivall (1907) 5: A Iackman [...] vseth to make counterfaite licenses which they call Gybes, and sets to Scales, in their language called Iarkes.
c.1566		Harman Caveat for Common Cursetours in Viles & Furnivall (1907) 60: You shall vnderstande that a larkeman hathe his name of a Iarke, which is a scale in their Language, as one should make writinges and set scales for lycences and pasporte.
1592		Groundworke of Conny-catching Ch. 15: A Jarke, which is a seale in their language.
1608		Dekker Belman of London (3rd edn) D2: A counterfeit Licence to beg from towne to towne, which licence they call a Gybe, and the Seales to it, Iarkes.
1621		Jonson Masque of the Gipsies in Q. Horatius Flaccus (1640) 48: Therefore (till with his painfull Progenitors, he be able to beate it on the hoofe to the bene bouse, or the stauling Ken, to nip a ian, or clye the Iarke) ’tis thought fit he marche in the Infants Equipage.
1665		Head Eng. Rogue I 50: Jarke, A Seal.
1674		Head Canting Academy (2nd edn) 54: They have alwaies a Counterfeit pass or Licence which they call a Gybe, and the Seal thereunto Jarkes.
1688		R. Holme Academy of Armory Ch. iii item 68c: Canting Terms used by Beggars, Vagabonds, Cheaters, Cripples and Bedlams. [...] Jerke, a Seal. Jerk’t, Sealed.
c.1698		B.E. Dict. Canting Crew n.p.: Jarke A Seal.
1725		New Canting Dict. [as cit. c.1698].
1728		Defoe Street Robberies Considered 32: Jarke, a Seal.
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict. [as cit. c.1698].
1754		Scoundrel’s Dict. 19: A Seal – Jark.
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue.
1809		G. Andrewes Dict. Sl. and Cant n.p.: Jacken closer a seal.
1818		W. Scott Heart of Mid-Lothian (1883) 260: Deil a gude fellow that has been but twelvemonth on the lay, be he ruffler or padder, but he knows my gybe as well as the jark of e’er a queer cuffin in England – and there’s rogue’s Latin for you.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.
1835		G. Kent Modern Flash Dict. 19: Jacken closer – a seal [...] Jackrum – license for marriage.
1848		Flash Dict. in Sinks of London Laid Open.
1857		‘Ducange Anglicus’ Vulgar Tongue.
1859		Matsell Vocabulum.
1859		Hotten Dict. of Modern Sl. etc. 53: JARK, a seal or watch ornament. Ancient cant.
1859		Matsell Vocabulum 46: jark A Seal. [Ibid.] jurk A seal. [Ibid.] jasker A seal.
1864, 1867, 1870		Hotten Sl. Dict.

2. any trinket worn on a watch-chain.

1859, 1860		Hotten Dict. of Modern Sl. etc.
1864, 1867, 1870		Hotten Sl. Dict.

3. (UK campus) a safe-conduct pass.

1864, 1867, 1870		Hotten Sl. Dict.
1873		Sl. Dict.

4. a watch.

1984

Partridge DSUE (8th edn) 613/1: C.19–20.