The key. As there are ten cards, and ten lines on every card, the following ten are the first lines on the black side of each of them, viz. ...
Walpole, Horace,1717-1797.
[London] : Printed for L. Donnelly; and A. M'Culloh, printer, at the Bible and Lamb without Temple-Bar, price 2s.6d. Where any purchaser, to whom this key is not satisfactory, may see the method, and be made perfect in the secret in five minutes, so as to discover the thonghts [sic] of another without the key,
[1780?]
The key to 'The impenetrable secret', a trick of cards attributed to Horace Walpole.
ESTC