E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
The courage excited by drink; pot valour.
In the Dutch wars (in the time of Charles II.), . the captain of the Hollander man-of-war, when about to engage with our ships, usually set . a hogshead of brandy abroach before the mast, and bid the men drink . and our men felt the force of the brandy to their cost.Notes and Queries (Oct. 15, 1892, p. 304).