ghts have been far from encouraging.

Three Kinds of Aeroplanes.

There are three forms of aeroplanes, with all of which more or less
success has been attained. These are:

The monoplane, a one-surfaced plane, like that used by Bleriot.

The biplane, a two-surfaced plane, now used by the Wrights, Curtiss,
Farman, and others.

The triplane, a three-surfaced plane This form is but little used,
its only prominent advocate at present being Elle Lavimer, a Danish
experimenter, who has not thus far accomplished much.

Whatever of real success has been accomplished in aviation may be
credited to the monoplane and biplane, with the balance in favor of
the latter. The monoplane is the more simple in construction and, where
weight-sustaining capacity is not a prime requisite, may probably be
found the most convenient. This opinion is based on the fact that the
smaller the surface of the plane the less will be the resistance offered
to the air, and the greater will be the speed at which the machine
may be moved. On the other hand, the biplane has a much greater plane
surface (double that of a monoplane of the same size) and consequently
much greater weight-carrying capacity.

Differences in Biplanes.

While all biplanes are of the same general construction so far as the
main planes are concerned, each aviator has his own ideas as to the
"rigging."

Wright, for instance, places a double horizontal rudder in front, with
a vertical rudder in the rear. There are no partitions between the
main planes, and the bicycle wheels used on other forms are replaced by
skids.

Voisin, on the contrary, divides the main planes with vertical
partitions to increase stability in turning; uses a single-plane
horizontal rudder in front, and a big box-tail with vertical rudder at
the rear; also the bicycle wheels.

Curtiss attaches horizontal stabilizing surfaces to the upper plane;
has a double horizontal rudder in front, with a vertical rudder
and horizontal stabilizing surfaces in rear. Also the bicycle wheel
alighting gear.

CHAPTER V. CONSTRUCTING A GLIDING MACHINE.

First decide upon the kind of a machine you want--monoplane, biplane,
or triplane. For a novice the biplane will, as a rule, be found the
most satisfactory as it is more compact and therefore the more easily
handled. This will be easily understood when we realize that the surface
of a flying machine should be laid out in proportion to the amount of
weight it will