became tired with their laborious work. Mr. Taylor, student of
divinity, and tutor of Mr. Miller's sons, was on board, and seeing the
exhausted state of the men at the capstan, suggested the employment of
steam-power. Mr. Miller was pleased with the idea, and resolved to
make inquiry upon the subject.

At that time William Symington, a young engineer from Wanlockhead,
was exhibiting a road locomotive in Edinburgh. He was a friend of
Taylor's, and Mr. Miller went to see the Symington model. In the
course of his conversation with the inventor, he informed the latter of
his own project, and described the difficulty he had experienced in
getting his paddle-wheels turned round. On which Symington immediately
asked, "Why don't you use the steam-engine?" The model which Symington
exhibited, produced rotary motion by the employment of ratchet-wheels.
The rectilinear motion of the piston-rod was thus converted into rotary
motion. Mr. Miller was pleased with the action of the ratchet-wheel
contrivance, and gave Symington an order to make a pair of engines of
that construction. They were to be used on a small pleasure-boat on
Dalswinton Lake.

The boat was constructed on the double-hull or twin plan, so that the
paddle should be used in the space between the hulls.*
[footnote...
This steam twin boat was in fact the progenitor of the Castalia,
constructed about a hundred years later for the conveyance of
passengers between Calais and Dover.
...]

After much vexatious delay, arising from the entire novelty of the
experiment, the boat and engines were at length completed, and removed