Green’s Dictionary of Slang

(UK und.) a specially made dice box used as a means of cheating.

1831		Satirist (London) 6 Nov. 246/1: False dice and boxes, technically called ‘scratches,’ ‘dispatches,’ and ‘securers’.
1832		Satirist (London) 22 Jan. 31/1: [T]he numerous implements for swindling used at [hazard] [...] Cog, or Secure, / Doctor, or Close Box, Smooth Box, Dispatches, [...] The Scratch.