A unit devised by the British engineer John Smeaton (1724 – 1792) to describe the efficiency of steam engines used for pumping water (as the earliest engines were). It is the number of millions of pounds of water raised 1 foot by burning 1 bushel of coal. Symbol, m.
Typical duties in the era of Newcomen engines were around 4m to 6m.
Copyright © 2003. Sizes, Inc. All rights reserved.
Last revised: 16 August 2003.