Our modern mechanical age began with machines powered by steam. Steam was produced by heating water, using wood or coal as fuel. The steam was then used to push and pull a piston up and down inside a cylinder. This powerful motion was transferred to a beam or lever, which in turn made other parts move to perform specific tasks. One of the first successful steam-powered machines was improved by James Watt in 1782. The large wheel of the engine turned many other wheels inside a cotton mill. These smaller wheels turned quickly to drive spinning machines.