ALCOHOL MEASURES
From		To	Multiply by
gill(UK)		pint	4.0
gill(UK)		litres	0.1420
butt		hogsheads	2.0
hogshead		US barrels	2.0
hogshead		US gallons	63
hogshead		Imperial gallons	52.5
tun		hoggsheads	4
firkin		Imperial Gallons	9
firkin		barrel (UK)	0.24
firkin		litres	40.915

The Hogshead: Traditionally the hogshead equalled differing amounts of ale (48), beer (54), cider (60), oil, honey or wine (63) or molasses (100)

Gill: The US gill is 4 fluid ounces or 180millilitres

The US barrel is less than the UK barrel at 31 US gallons or 117.3 litres. a UK barrel is 36 UK gallons or 163.7 litres.