In 1875, at Taunton, special prizes were awarded for onehorse and two-horse mowing-machines, hay-making machines, horse-rakes (self-acting and not self-acting), guards to the drums of threshing-machines, and combined guards and feeders to the drums of threshing-machines.
Gravity or self-acting planes are for lowering loaded cars, one or more at a time, from a higher to a lower level.
Self-acting tanks are occasionally built underneath the platforms of hoisting cages.
In a large colliery where the shafts are situated near the centre of the field, and the workings extend on all sides, both to the dip and rise, the drawing roads for the coal may be of three different kinds - (r) levels driven at right angles to the dip, suitable for horse roads, (2) rise ways, known as jinny roads, jig-brows, or up-brows, which, when of sufficient slope, may be used as self-acting planes, i.e.
A road maybe used as a self-acting or gravitating incline when the gradient is r in 30 or steeper, in which case the train is lowered by a rope passing over a pulley or brake drum at the upper end, the return empty train being attached to the opposite end of the rope and hauled up by the descending load.