and Lieutenant V.H.N. Wadham of the Royal Flying Corps (RFC) reported von Kluck's forces were preparing to surround the British Expeditionary Force, contradicting all other intelligence. The British High Command took note of the report and started to withdraw from Mons, saving the lives of 100,000 soldiers. Later, during the First Battle of the Marne, observation aircraft discovered weak points and exposed flanks in the German lines, allowing the allies to take advantage of them. In Germany the great successes of the early Zeppelin airships had largely overshadowed the importance of heavier-than-air aircraft. Out of a paper strength of about 230 aircraft belonging to the army in August 1914 only 180 or so were of any use. The French military aviation exercises of 1911, 1912, and 1913 had pioneered cooperation with the cavalry (reconnaissance) and artillery (spotting), but the momentum was, if anything, slacking. The United Kingdom had "started late" and initially relied largely on the French aircraft industry, especially for aircraft engines. The initial British contribution to the total allied airwar effort in August 1914 (of about 184 aircraft) was three squadrons with about 30 serviceable machines. By the end of the war, the British Armed Forces had formed the world's first air force to be independent of either army or naval control, the Royal Air Force. The United States Armed Forces air services were far behind; even in 1917, when the United States entered the war, they were to be almost totally dependent on the French and British aircraft industries for combat aircraft. The Germans' great air "coup" of 1914 was at the Battle of Tannenberg in East Prussia, where an unexpected Imperial Russian Army attack was reported by Leutnants Canter and Mertens, resulting in the Russians being forced to withdraw. Early Western Front reconnaissance duties By the end of 1914 the line between the Imperial German Army and the Allied powers stretched from the North Sea to the Alps. The initial "war of movement" largely ceased, and the front became static. Three main functions of short range reconnaissance squadrons had emerged by March 1915. The first was photographic reconnaissance: building up a complete mosaic map of the enemy trench system. The first air cameras used glass plates. (Photographic film had been invented by Kodak, but did not at this stage have sufficient resolution). Artillery "spotting" enabled the ranging of artillery on targets invisible to the gunners. Radio