Anker

A small Dutch cask of about 38 litres, sized so that a single person could carry it, and the standard vessel of the Georgian contraband trade.

Every other cask in British use was sized for a cellar, a cart or a ship's hold. The anker was sized for a man's back. Dutch gin and French brandy crossed the Channel in ankers because a landing party could move a cargo from boat to beach to hiding place without a wheel or a winch, working in darkness and at speed. Its capacity is usually given as ten old wine gallons, which is where the round figure in period sources comes from, and which converts to a distinctly unround eight and a half imperial gallons after the 1824 unification. Ankers were frequently slung in pairs over a horse, and revenue officers searching a coastal village knew exactly what shape they were looking for.