The steam engine familiarly explained and illustrated; with an historical sketch of its invention and progressive improvement; its applications to navigation and railways; with plain maxims for railway speculators. By the Rev. Dionysius Lardner ... With additions and notes by James Renwick ...

STEAM NAVIGATION. 261
y the modification in question. On a-comparison of'the
respective logs of the two vessels, it appeared that. the
CONFIANCE had gained by the alteration in her wheels an
increase of speed amounting to 2 knots on 7 in smooth
water, and 24 knots on 4 to 42 knots in rough weather; that
the action of the paddles did not bring up the engine or
retard their velocity in a head sea; that- in rolling their
action assisted in righting the vessel; and that the wear and
strain, as well on the vessel as on the engines, were materially reduced. With re~pect to the durability of these
wheels, the commander of the FLAMER- reported in January,
1834, that in six weeks of the most tempestuous weather
they found them to act remarkably well, without even- a
single float being shifted."
This paddle wheel is represented in fig. 68. The contrivance may be shortly stated to consist in causing the
wheel which bears the paddles to revolve on one centre, and::
the radial arms which move the paddles to revolve on another.
centre. Let A B C D E F G H I be the polygonal circumference of the paddle wheel, formed of straight bars, securely
connected together at the extremities of the spokes: or radii
of the wheel which turns on the shaft- which is worked by
the engine; the centre of this wheel being at o. So far this
wheel is similar to the common paddle wheel; but the paddle
boards are not, as in the common wheel, fixed at A B C,
&c., so as to be always directed to the centre o, but are so
placed that: they are capable of- turning: on axles which are
always horizontal, so that they can take any angle with
respect to the water which may be given to them. From the
centres, or the line joining the pivots on which these paddle
boards turn, there proceed short arms K, firmly fixed to the
* See a more detailed: account of these reports in the Mechanic's; Magazinej vol. xxii. page 274, from, which I have taken the drawing of this.
paddle wheel; and also see Report of the Committee of the House of
Commons on Steam Navigation to India, Evidence of William Morgan
age 95.