Green’s Dictionary of Slang

bully adv.

very well.

1846		Carlton Home Ballads 86: You’re doin’ the politics bully, as all our family agree [...] [F&H].
1863		G.W. Whitman in Civil War Letters 25 Feb. 89: I shall have my tent fixed up Bully in a day or two.
1872		‘Mark Twain’ Innocents at Home 334: Put Buck through as bully as you can, pard.
1887		E. Custer Tenting on the Plains (rev. edn 1895) 388: All the boys done bully.
1900		H. Garland Eagle’s Heart 53: He’s a dandy ball-player, and skates bully.
1909		W.M. Raine Brand Blotters (1912) 194: You put that across bully. Never saw it done better.
1927		(con. 1910s) S. Lewis Elmer Gantry 287: And yet you see how bully it [i.e. a photograph] came out!