DARK LANTHORN, subs. phr. (old).See quots.
c. 1696. B. E., A New Dictionary of the Canting Crew, s.v. A DARK LANTHORN, the Servant or Agent that Receives the Bribe (at Court).
1725. A New Canting Dictionary, s.v.
1785. GROSE, A Classical Dictionary of the Vulgar Tongue, s.v. DARK LANTHORN, a servant, or agent at Court, who receives a bribe for his principal or master.
1811. GROSE and CLARKE, Lexicon Balatronicum, s.v.