The boat at Swansea was partly made under Mr. (now Sir William) Grove's
directions, and the engine was worked on the principle of the old toys
of Ritchie, which consisted of six radiating poles projecting from a
spindle, and rotating between a large electro-magnet. Three persons
traveled in Hunt's boat, at the rate of three miles per hour. Eight
large Grove's cells were employed, but the expense put it out of
question as a practical application.

Had the Gramme or Siemens machine existed at that time, no doubt the
subject would have been further advanced, for it was not merely the cost
of the battery which stood in the way, but the inefficient motor, which
returned only a small fraction of the power furnished by the zinc.

Professor Silvanus Thompson informs us that an electric boat was
constructed by Mr. G. E. Dering, in the year 1856, at Messrs. Searle's
yard, on the River Thames; it was worked by a motor in which rotation
was effected by magnets arranged within coils, like galvanometer
needles, and acted on successively by currents from a battery.

From a recent number of the _Annales de l'Electricite_, we learn that
Count de Moulins experimented on the lake in the Bois de Boulogne, in
the year 1866, with an iron flat-bottomed boat, carrying twelve persons.
Twenty Bunsen cells furnished the current to a motor on Froment's
principle turning a pair of paddle wheels.

In all these reports there is a lack of data. We are interested to
know what power the motors developed, the time and speed, as well as
dimensions and weights.