Engines of Miller's double pleasure boat, 1788.

Lithograph by C F Cheffins after a drawing by H B Barlow, of the steam engine built by William Symington (1763-1831), now in the Science Museum. In 1788 it was used in the the first experimental steamboat, built by Patrick Miller (1731-1815), an Edinburgh banker. The engine had two single-action cylinders, with separate condensers, which drove two paddle shafts by chains and ratchets, and propelled the steamboat on Dalswinton Loch, near Dumfries in Scotland, at five knots. Illustration from 'A sketch of the origin and progress of steam navigation from authentic documents' by steam navigation pioneer Bennet Woodcroft (1803-1879) published in London in 1848.