ively in these later years of accomplished flight that the
machine which Langley launched on the Potomac River in October of 1903
was fully capable of sustained flight, and only the accidents incurred
in launching prevented its pilot from being the first man to navigate
the air successfully in a power-driven machine.

The best account of Langley's work is that diffused throughout a weighty
tome issued by the Smithsonian Institution, entitled the Langley Memoir
on Mechanical Flight, of which about one-third was written by Langley
himself, the remainder being compiled by Charles M. Manly, the engineer
responsible for the construction of the first radial aero-engine, and
chief assistant to Langley in his experiments. To give a twentieth
of the contents of this volume in the present short account of the
development of mechanical flight would far exceed the amount of space
that can be devoted even to so eminent a man in aeronautics as S.
P. Langley, who, apart from his achievement in the construction of a
power-driven aeroplane really capable of flight, was a scientist of no
mean order, and who brought to the study of aeronautics the skill of the
trained investigator allied to the inventive resource of the genius.

That genius exemplified the antique saw regarding the infinite capacity
for taking pains, for the Langley Memoir shows that as early as 1891
Langley had completed a set of experiments, lasting through years,
which proved it possible to construct machines giving such a velocity
to inclined surfaces that bodies indefinitely heavier than air could
be sustained upon it and propelled through it at high speed. For full
account (very full) of these experiments, and of a later series leading
up to the construction of a series of 'model aerodromes' capable of
flight under power, it is necessary to turn to the bulky memoir of
Smithsonian origin.

The account of these experiments as given by Langley himself reveals
the humility of the true investigator. Concerning them, Langley remarks
that, 'Everything here has been done with a view to putting a trial
aerodrome successfully in flight within a few years, and thus giving an
early demonstration of the only kind which is conclusive in the eyes of
the scientific man, as well as of the general public--a demonstration
that mechanical flight is possible--by actually flying. All that has
been done has been with an eye principally to this immediate result,
and all the experiments g