Green’s Dictionary of Slang

1. a servant girl.

1885		Bulletin (Sydney) 22 Aug. 10/4: Mothers are not quite so vulgar as to rear their own children in this enlightened age. The party who agitates the cradle, and forms a youngster’s character now, is the slab-sided, fiery-headed Bridget, or the ‘rorty’ little Jemima Hann, who sees more of a child in one week than its high-toned Ma does in one year.
1902		H. Baumann Londinismen (2nd edn).

2. a chamberpot [its removal is one of the servant’s tasks].

1889–90		Barrère & Leland Dict. of Sl., Jargon and Cant.
1890–1904		Farmer & Henley Sl. and Its Analogues.

3. in pl., elastic-sided boots; also attrib. [ety. unknown; ? a brandname or link to jemmy adj.¹ (3)].

1900		Sporting Times 2 June 4/1: The senior officers are allowed by an unwritten code to wear Jemima boots at mess.
1930		A. Lyall It isn’t Done 36: Those curious elastic-sided boots with sham buttons known as Jemimas.
1936		‘Banjo’ Paterson Shearer’s Colt 17: Wears a barber’s delight [silk shirt] and jemimas [elastic-sided boots], but the dressier they are the hotter they are.