and left-handed, 3 ft. in diameter, with four blades each,
occupying three-quarters of the area of the circumference, set
at an angle of 60 degrees. A considerable time was spent in
perfecting the motive power. Compressed air was tried and
abandoned. Tappets, cams, and eccentrics were all tried, to work
the slide valve, to obtain the best results. The piston rod of
engine passed through both ends of the cylinder, and with long
connecting rods worked direct on the crank of the propellers.
From memorandum of experiments still preserved the following is
a copy of one: June, 27th, 1845, water 50 ozs., spirit 10 ozs.,
lamp lit 8.45, gauge moves 8.46, engine started 8.48 (100 lb.
pressure), engine stopped 8.57, worked 9 minutes, 2,288
revolutions, average 254 per minute. No priming, 40 ozs. water
consumed, propulsion (thrust of propellers), 5 lbs. 4 1/2 ozs.
at commencement, steady, 4 lbs. 1/2 oz., 57 revolutions to 1 oz.
water, steam cut off one-third from beginning.

'The diameter of cylinder of engine was 1 1/2 inch, length of
stroke 3 inches.

'In the meantime an engine was also made for the smaller model,
and a wing action tried, but with poor results. The time was
mostly devoted to the larger model, and in 1847 a tent was
erected on Bala Down, about two miles from Chard, and the model
taken up one night by the workmen. The experiments were not so
favourable as was expected. The machine could not support
itself for any distance, but, when launched off, gradually
descended, although the power and surface should have been
ample; indeed, according to latest calculations, the thrust
should have carried more than three times the weight, for there