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Bird's eye color view of reservoirs, green areas of foliage, pink roads and blue water, with a dam prominent

Fairmount and vicinity, 1839

Frederick Graff’s drawing of the 1815 steam engine, adapted from a design by Englishmen Matthew Boulton and James Watt, shows the engine from the north, with Faire Mount and the reservoirs to the left of the drawing and the river to the right. The 1815 engine sat on the south side of the Engine House and was thus called the South Engine. As Graff indicated in his drawing, the Engine House was essentially open from river level to the roof in order to accommodate the massive beam and fly wheel of the two engines. While Graff showed the crank attached to the axle of the fly wheel, he left the crank shaft and the pump out of the drawing. The North Engine, designed and built in 1816 by Philadelphian Oliver Evans, advanced steam engines’ operating pressures from 2 pounds per square inch (psi) to 200 psi, a significant technological achievement.

Steam engine drawing, Frederick Graff Sr., 1815

Apparatus for testing Model Turbine Engines used at Fairmount, 1859-60

Apparatus for testing model turbine wheels used at Fairmount, 1859-60

New Mill House at Fairmount (2008.001.0046)

New Mill House at Fairmount

Jonval Turbines at New Mill House, 1870