xty miles an hour was the least
figure desirable in an aeroplane, and this should be exceeded as much as
possible. Actually, the Wright machine had a speed of 38 miles per hour,
while Farman's Voisin machine flew at 45 miles per hour.

Both machines were extremely sensitive to high winds, and the speaker,
in spite of newspaper reports to the contrary, had never seen either
flown in more than a gentle breeze. The damping out of the oscillations
of the flight path, discussed in the last lecture, increased with the
fourth power of the natural velocity of flight, and rapid damping
formed the easiest, and sometimes the only, defense against dangerous
oscillations. A machine just stable at 35 miles per hour would have
reasonably rapid damping if its speed were increased to 60 miles per
hour.

Thinks Use Is Limited.

It was, the lecturer proceeded, inconceivable that any very extended use
should be made of the aeroplane unless the speed was much greater than
that of the motor car. It might in special cases be of service,
apart from this increase of speed, as in the exploration of countries
destitute of roads, but it would have no general utility. With an
automobile averaging 25 to 35 miles per hour, almost any part of Europe,
Russia excepted, was attainable in a day's journey. A flying machine
of but equal speed would have no advantages, but if the speed could be
raised to 90 or 100 miles per hour, the whole continent of Europe
would become a playground, every part being within a daylight flight of
Berlin. Further, some marine craft now had speeds of 40 miles per hour,
and efficiently to follow up and report movements of such vessels an
aeroplane should travel at 60 miles per hour at least. Hence from
all points of view appeared the imperative desirability of very high
velocities of flight. The difficulties of achievement were, however,
great.

Weight of Lightest Motors.

As shown in the first lecture of his course, the resistance to motion
was nearly independent of the velocity, so that the total work done in
transporting a given weight was nearly constant. Hence the question of
fuel economy was not a bar to high velocities of flight, though should
these become excessive, the body resistance might constitute a large
proportion of the total. The horsepower required varied as the
velocity, so the factor governing the maximum velocity of flight was
the horsepower that could be developed on a given weight. At present the
w