A roasting jack is a machine which rotates meat roasting on a spit. It can also be called a spit jack, a spit engine or a turnspit, although this name can also refer to a human turning the spit, or a turnspit dog. Cooking meat on a spit dates back at least to the 1st century BC, but at first spits were turned by human power. In Britain, starting in the Tudor period, dog-powered turnspits were used; the dog ran in a treadmill linked to the spit by belts and pulleys. Other forms of roasting jacks included the steam jack, driven by steam, the smoke jack, driven by hot gas rising from the fire, and the bottle jack or clock jack, driven by weights or springs.