ing surfaces was about three hundred and five square feet.
The operator lay on his face in the middle of the lower plane. The
horizontal rudder in front had a supporting surface of fifteen square
feet. The vertical tail, as they called it, which was the true rudder,
was reduced after trial to six square feet. The machine was supported on
the ground by skids, and was very strongly built. It weighed a hundred
and sixteen and a half pounds, to which must be added about a hundred
and forty pounds for the weight of the operator. It performed about a
thousand glides, with only one injury, though it made many hard landings
at full speed on uneven ground. The longest glide was 622-1/2 feet,
traversed in twenty-six seconds. The glides were made from the Kill
Devil sand-hills, near Kitty Hawk--mounds of sand heaped up by the wind,
the biggest having a height of a hundred feet.

The time had now come to invite an engine to bear a part in the
proceedings. In the autumn of 1903 the brothers returned to Kitty Hawk
for their fourth season of experiment. They had built in the winter a
machine weighing six hundred pounds, including the operator and an eight
horse-power motor. Finding that the motor gave more power than had been
estimated, they added a hundred and fifty pounds of weight in
strengthening the wings and other parts. The airscrews, built from their
own calculations, gave in useful work two-thirds of the power expended.
Before trying this machine, however, they continued their practice with
the old glider, and made a number of flights in which they remained in
the air for over a minute, often soaring for a considerable time in one
spot, without any descent at all.

It was late in the season, the 17th of December 1903, when they first
tried the power machine. A general invitation to be present at the trial
had been given to the people living within five or six miles, but 'not
many were willing to face the rigours of a cold December wind in order
to see, as they no doubt thought, another flying machine _not_ fly'.
Five persons besides the brothers were present. Mr. Orville Wright's
narrative, written for the Aeronautical Society of Great Britain, must
be given in his own words:

'On the morning of December 17th, between the hours of 10.30 o'clock and
noon, four flights were made, two by Mr. Orville Wright, and two by Mr.
Wilbur Wright. The starts were all made from a point on the levels, and
about 200 feet west of our camp, w