Green’s Dictionary of Slang

corks n.²

a butler.

1856		W. Surrey Times 27 Sept. 4/6: Corks, the butler of the Bishop of Tawnyport.
1864, 1867, 1870		Hotten Sl. Dict.
1873		Sl. Dict.
1889–90		Barrère & Leland Dict. of Sl., Jargon and Cant.
1890–1904		Farmer & Henley Sl. and Its Analogues.