Green’s Dictionary of Slang

1. a theatrical box.

1934		E. Shanks John o’ London’s Weekly 8 Dec. n.p.: As in ‘Once I happened to mention to [a] manager... that my children would like to see the pantomime he was producing. “Right you are, old man,” he said, “give me a ring any time and I’ll see there’s a Charles James for them.” It took me some moments to realise that he meant a box, and I suppose that no one unacquainted with the peculiarities for [? of] rhyming slang would have realised it at all’.
1981		P. Wright Cockney Dialect and Sl. 103: Charles James Fox ‘box’.

2. (hunting) a fox.

1984		Partridge DSUE (8th edn) 198/2: late C.19–20.
2002		B. Kirkpatrick Wicked Cockney Rhy. Sl.