The earliest known steam turbine was built by Hero of Alexandria in the first century A.D. Called the Sphere of Aeolus, the device consisted of a hollow sphere that could be made to rotate at high speed by feeding the interior of the sphere with steam, which escaped through small spouts resembling elbows. In 1629 Giovanni Branca told how a wheel could be turned by allowing jets of steam to hit vanes attached to the wheel's outer rim. However, the significant drawback to this simple idea was the need for the wheel to revolve with unheard of velocity to absorb even a useful fraction of the energy of the steam.

The first steam turbines with any commercial use were those built in 1831 by William Avery in the United States. About 50 of his crude turbines were made and used in sawmills and even on a locomotive. But...