ly them, as best they might, to the
difficulties with which they were familiar in practice. So it was also
with the application of wireless telegraphy to aircraft. The men of the
laboratory were not familiar with all the conditions which had to be
observed, nor with all the unforeseen obstacles which present themselves
in practice. It remained for those who knew the conditions and the
obstacles to work out the practical problem for themselves. The
vibration and noise, which make it difficult in an aeroplane to hear
anything but the engine, the risk of fire, and the imperfect protection
of the instruments from splashes of oil and the rush of the air--all
these things complicated the problem.

As early as 1907 Captain Llewelyn Evans, who commanded the 1st Wireless
Company of the Royal Engineers at Aldershot, lent his help to Colonel
Capper of the balloon school in devising wireless communication between
aircraft and the ground. The apparatus had to be extemporized. The first
experiments were made by Lieutenant C. J. Aston, R.E., in a captive
balloon. In May 1908 a free run was made in the balloon _Pegasus_, in
which a receiving set of wireless had been installed. When the balloon
was over Petersfield, Lieutenant Aston received very good signals from
the Aldershot wireless station twenty miles distant. During the same
month the sending of messages from the balloon was also tried with
promising results.

These experiments soon came to an end. The time was not ripe for further
developments. No airships or aeroplanes were as yet in use in England,
and all available energy had to be concentrated on producing wireless
telegraphy sets for the use of the army. In October 1909 Captain H. P.
T. Lefroy, R.E., was placed in charge of all experimental work in
wireless telegraphy for the army. This appointment he retained until the
outbreak of the war. He had been commissioned in the Royal Engineers in
1899, and had begun to study wireless at Gibraltar in 1905. Approaching
the question from the service side, he was able to do much to adapt
wireless telegraphy to the new conditions presented by the conquest of
the air. As soon as the army airship _Beta_ was available he had her
equipped with wireless apparatus, and on the 27th of January 1911 went
up in her from Farnborough. Many messages were sent from the airship to
the ground station up to a range of thirty miles, and for a short time,
while the airship engine stopped running, it wa