Green’s Dictionary of Slang

a sovereign, thus half a skiv, a half-sovereign, ten shillings.

1859		Hotten Dict. of Modern Sl. etc. 93: SKID, a sovereign.
1868		letter to Editor Daily News 25 Sept. 5/1: My son [...] had just borrowed what he called ‘half a skid’ from me.
1871		Westmoreland Gaz. 14 Oct. 2/4: Governors are improved [...] since the old days, for they tip you half a skiv now, instead of a cartwheel [...] I‘ll fork out a tizzy for you.
1873		Sl. Dict. 292: Skid a sovereign. Fashionable slang. Occasionally skiv.
1887		J. Payn Glow-Worm Tales III 76: My Dear Uncle,—Please to send me the skiv by return, for I sadly want some comfort.
1888		Herts & Cambs Reporter 20 Jan. 6/3: A silver coin upon the ground, / William Sykes one morning found / ‘Oh!’ he cried [...] 'This here Joey, as I live, / I will pass for half a “skiv”’.
1890		Sporting Times 15 Feb. 1/3: He offered to Bet that he would Lie Down right where he Was for an Hour, and Nary a Hopper should Move him. ‘Done for a Skiv.’.