know it to-day, and bring this ultra-material age to
a phase of ruin on which saner people can build a world more reasonable
and less given to groping after purely material advancement.

PART II. 1903-1920: PROGRESS IN DESIGN

By Lieut.-Col. W. Lockwood Marsh

I. THE BEGINNINGS

Although the first actual flight of an aeroplane was made by the Wrights
on December 17th 1903, it is necessary, in considering the progress
of design between that period and the present day, to go back to
the earlier days of their experiments with 'gliders,' which show the
alterations in design made by them in their step-bystep progress to a
flying machine proper, and give a clear idea of the stage at which they
had arrived in the art of aeroplane design at the time of their first
flights.

They started by carefully surveying the work of previous experimenters,
such as Lilienthal and Chanute, and from the lesson of some of the
failures of these pioneers evolved certain new principles which were
embodied in their first glider, built in 1900. In the first place,
instead of relying upon the shifting of the operator's body to obtain
balance, which had proved too slow to be reliable, they fitted in front
of the main supporting surfaces what we now call an 'elevator,' which
could be flexed, to control the longitudinal balance, from where the
operator lay prone upon the main supporting surfaces. The second
main innovation which they incorporated in this first glider, and the
principle of which is still used in every aeroplane in existence, was
the attainment of lateral balance by warping the extremities of the main
planes. The effect of warping or pulling down the extremity of the wing
on one side was to increase its lift and so cause that side to rise. In
the first two gliders this control was also used for steering to right
and left. Both these methods of control were novel for other than model
work, as previous experimenters, such as Lilienthal and Pilcher, had
relied entirely upon moving the legs or shifting the position of the
body to control the longitudinal and lateral motions of their gliders.
For the main supporting surfaces of the glider the biplane system of
Chanute's gliders was adopted with certain modifications, while the
curve of the wings was founded upon the calculations of Lilienthal as to
wind pressure and consequent lift of the plane.

This first glider was tested on the Kill Devil Hill sand-hills in North
Carol