pursuits other than watching balloon ascents, however, and
the joys of the air were confined to a few adventurous spirits, such as
Green and Holland, who first substituted coal gas for hydrogen and in
1836 made a voyage of 500 miles from Vauxhall Gardens to Weilburg in
Nassau, and James Glaisher, who in the middle of the century began to
make meteorological observations from balloons, claiming on one
occasion, in 1862, to have reached the great height of 7 miles.

FIRST EXPERIMENTS IN GLIDERS AND AEROPLANES.

The world seemed content to have achieved the balloon, but there were a
few men who realized that the air had not been conquered, and who
believed that success could only be attained by the scientific study and
practice of gliding. Prominent among these, Sir George Cayley, in 1809,
published a paper on the Navigation of the Air, and forecasted the
modern aeroplane, and the action of the air on wings. In 1848 Henson and
Stringfellow, the latter being the inventive genius, designed and
produced a small model aeroplane--the first power-driven machine which
actually flew. It is now in the Smithsonian Institute at Washington. Of
greater practical value were the gliding experiments by Otto Lilienthal,
of Berlin, and Percy Pilcher, an Englishman, at the end of the last
century. Both these men met their death in the cause of aviation.
Another step forward was made by Laurence Hargrave, an Australian, who
invented the box and soaring kite and eighteen machines which flew.

From the theoretical point of view, Professor Langley, an American,
reached in his _Experiments in Aerodynamics_ the important conclusion
that weight could best be countered by speed. From theory Langley turned
to practice and in 1896 designed a steam-driven machine which flew
three-quarters of a mile without an operator. Seven years later, at the
end of 1903, he produced a new machine fitted with a 52 horse-power
engine weighing less than 5 lb. per horse-power; but this machine was
severely damaged ten days before Wilbur Wright made his first flight in
a controlled power-driven aeroplane.

THE WRIGHT BROTHERS AND THEIR SUCCESSORS IN EUROPE.

The Wright brothers directed their whole attention to aviation in 1899.
By 1902, as the result of many experiments, they had invented a glider
with a horizontal vane in front, a vertical vane behind, and a device
for "warping" the wings. Their longest glide was 622-1/4 feet. This was
followed by the construct