of water on which to try his model
boats. The reservoir of the Old Welsh Harp was close at hand--a place
famous for its water-birds and wild fowl.

Smith made many models of boats, his experiments extending over many
years. In 1834, he constructed a boat propelled by a wooden screw
driven by a spring, the performance of which was thought extraordinary.
Where he had got his original idea is not known. It was floating about
in many minds, and was no special secret. Smith, however, arrived at
the conclusion that his method of propelling steam vessels by means of
a screw was much superior to paddles--at that time exclusively
employed. In the following year, 1835, he constructed a superior
model, with which he performed a number of experiments at Hendon. In
May 1836, he took out a patent for propelling vessels by means of a
screw revolving beneath the water at the stern. He then openly
exhibited his invention at the Adelaide Gallery in London. Sir John
Barrow, Secretary to the Admiralty, inspected the model, and was much
impressed by its action. During the time it was publicly exhibited, an
offer was made to purchase the invention for the Pacha of Egypt; but
the offer was declined.

At this stage of his operations, Smith was joined by Mr. Wright,
banker, and Mr. C. A. Caldwell, who had the penetration to perceive
that the invention was one of much promise, and were desirous of
helping its introduction to general use. They furnished Smith with the
means of constructing a more complete model. In the autumn of 1836, a
small steam vessel of 10 tons burthen and six horse-power was built,
further to test the advantages of the invention. This boat was fitted
with a wooden screw of two whole turns. On the 1st of November the
vessel was exhibited to the public on the Paddington Canal, as well as
on the Thames, where she continued to ply until the month of September
1837.

During the trips upon the Thames, a happy accident occurred, which
first suggested the advantage of reducing the length of the screw. The
propeller having struck upon some obstacle in the water, about one-half
of the length of the screw was broken off, and it was found that; the
vessel immediately shot ahead and attained a much greater speed than
before. In consequence of this discovery, a new screw of a single turn
was fitted to her, after which she was found to work much better.

Having satisfied himself as to the eligibility of the propeller in