Photograph of engraving of original form of Barker's Mill

Photograph of engraving of original form of Barker's Mill (from Ferguson's Lectures on Mechanics c. 1767)

This engraving, taken from Ferguson's "Mechanics," 1767, shows a corn mill driven by a reaction turbine of the form proposed by Dr. Barker and put into practice by Dr. J. T. Desaguliers about 1743. A similar arrangement had been used by Hero in his steam turbine or aeolipile about A.D. 50