(1) Other sizes were the firkin (9 gallons; from medieval Dutch meaning u2018a fourthu2019, that is, a quarter of a barrel), kilderkin (18 gallon; half a barrel) and hogshead.(2) A kilderkin is an old English liquid measure, dating from about the 13th century, equal to 16 (old and ill-defined) gallons, or half a barrel.(3) If you take a barrel to be two kilderkins and a kilderkin to be two firkins (which are themselves, of course, nine gallons), then the saving works out at about 14p per pint.
