on is well
known, and consists of two cells, each of superposed surfaces with
vertical side fins, placed one behind the other and connected by a
rod or frame. This flies with great steadiness without a tail. Mr.
Hargrave's idea was to use a team of these kites, below which he
proposed to suspend a motor and propeller from which a line would be
carried to an anchor in the ground. Then by actuating the propeller the
whole apparatus would move forward, pick up the anchor and fly away. He
said: "The next step is clear enough, namely, that a flying machine with
acres of surface can be safely got under way or anchored and hauled to
the ground by means of the string of kites."

The first tentative experiments did not result well and emphasized the
necessity for a light motor, so that Mr. Hargrave has since been engaged
in developing one, not having convenient access to those which have been
produced by the automobile designers and builders.

Experiments With Glider Model.

And here a curious reminiscence may be indulged in. In 1888 the present
writer experimented with a two-cell gliding model, precisely similar to
a Hargrave kite, as will be confirmed by Mr. Herring. It was frequently
tested by launching from the top of a three-story house and glided
downward very steadily in all sorts of breezes, but the angle of descent
was much steeper than that of birds, and the weight sustained per square
foot was less than with single cells, in consequence of the lesser
support afforded by the rear cell, which operated upon air already set
in motion downward by the front cell, so nothing more was done with
it, for it never occurred to the writer to try it as a kite and he thus
missed the distinction which attaches to Hargrave's name.

Sir Hiram Maxim also introduced fore and aft superposed surfaces in his
wondrous flying machine of 1893, but he relied chiefly for the lift upon
his main large surface and this necessitated so many guys, to prevent
distortion, as greatly to increase the head resistance and this,
together with the unstable equilibrium, made it evident that the design
of the machine would have to be changed.

How Lilienthal Was Killed.

In 1895, Otto Lilienthal, the father of modern aviation, the man to
whose method of experimenting almost all present successes are due,
after making something like two thousand glides with monoplanes, added
a superposed surface to his apparatus and found the control of it much
improved.