He also invented the governor, to regu late the quantity of steam admitted from the boiler into the cylinder, and thus regulate the motion of the engine.
Another improvement, which, in point of the additional power gained, was more important than the parallel motion, and which indeed pre ceded it in point of time, was the ' Double-acting Engine,'  in which steam was introduced to act expansively on each side of the piston in the en gine.  He also invented the governor, to regu late the quantity of steam admitted from the boiler into the cylinder, and thus regulate the motion of the engine.  "To describe all the other inventions of a minor kind connected with the steam-engine which came from the prolific genius of Watt, would occupy too much space."