nd more and more importance was
accorded to the search for objectives. Remarkable results were attained
by air photography from December, 1914; and after January, 1915, the
regulation of artillery fire by wireless telegraphy was in general
practice. It was necessary to protect the airplanes attached to army
corps, and to clean up the air for their free circulation. This role
devolved upon the most rapid airplanes, which were then the
Morane-Saunier-Parasols, and in the spring of 1915 these formed the
first _escadrilles de chasse_, one for each army. Garros, already
popular before the war for having been the first air-pilot to cross the
Mediterranean, from Saint-Raphael to Bizerto, forced down a large
Aviatik above Dixmude in April, 1915. A few days later a motor breakdown
compelled him to land at Ingelminster, north of Courtrai, and he was
made prisoner.[18] The aviators, like the knights of ancient times,
sent one another challenges. Sergeant David--who was killed shortly
after--having been obliged to refuse to fight an enemy airplane because
his machine-gun jammed, dropped a challenge to the latter on the German
aerodrome, and waited at the place, on the day and hour fixed, at
Vauquois (noon, in June, 1915, above the German lines), but his
adversary never came to the rendezvous.

[Footnote 18: The romantic circumstances under which he escaped in
February, 1918, are well known.]

The Maurice Farman and Caudron airplanes were used for observation. The
Voisin machines, strong but slower, were more especially utilized for
bombardments, which began to be carried out by organized expeditions.
The famous raids on the Ludwigshafen factories and the Karlsruhe railway
station occurred in June, 1915. It was at the battle of Artois (May and
June, 1915) that aviation for the first time constituted a branch of the
army; and the work was chiefly done by the escadrilles belonging to the
army corps, which rendered very considerable services as scouts and in
aerial photography and destructive fire. But as an enemy chaser, the
airplane was still regarded with much distrust and incredulity. Some
said it was useless; was it not sufficient that the airplanes of the
army corps and those for bombardments could defend themselves? Others of
less extreme opinions thought it should be limited to the part of
protector. This opposition was overcome by the sudden development of the
German enemy-chasing airplanes after July, 1915, subsequent to our