Sir John French on the evening of the 22nd held a conference at Le Cateau, whereat the position of the Germans, so far as it was then known, was explained and discussed. At the close of the conference Sir John stated that owing to the retreat of the French Fifth Army, the British offensive would not take place. A request from General Lanrezac arrived at 11.0 p.m., asking for offensive action against the German right flank, which was pressing him back from the Sambre. This could not be undertaken, but Sir John French promised to remain in his position for twenty-four hours.

In his book, A Staff Officer's Scrap Book, Sir Ian Hamilton, who was attached to the Japanese army during the Russo-Japanese War, has the following entry: 'The Russians are sending up balloons to our front, and in front of the Twelfth Division. Judging by manœuvres and South African experiences, they should now obtain a lot of misleading intelligence.' Observation from the air, when the war broke out, had still to prove its worth. The Royal Flying Corps, though confident of its own ability, was a new and untried arm. In the early reports there are occasional inaccuracies. Some of the early observers, among those who were hastily enrolled to bring newly formed squadrons up to strength, had not much military knowledge, and were not practised in reading the appearances of things seen from the air. At the time of the battles of Ypres, 1914, observers of No. 6 Squadron, which had prepared itself in hot haste for foreign service, mistook long patches of tar on macadamized roads for troops on the move, and the shadows cast by the gravestones in a churchyard for a military bivouac. Mistakes like these, though they were not very many, naturally made commanding officers shy of trusting implicitly to reports from the air. Yet the early reports of the first four squadrons did show without any possibility of mistake how formidable the German movements were.

Sir John French remained at Mons and was led into fighting a battle in a perilous position against much superior forces. The air reports of the 22nd had given some hints of the success of von Bülow's army in crossing the Sambre, had indicated a possible enveloping movement from the direction of Grammont, and had revealed something of the strength of the enemy troops on the British front. On the following day the attack began on the position at Mons, and pilots and observers were flying over and behind the battle-field looking for enemy movements, and locating enemy batteries.

On the 24th the retreat was in progress. As early as the morning of the 23rd the Royal Flying Corps had begun to shift its quarters from Maubeuge to Le Cateau. The transport and machines of No. 3 Squadron moved southward on that day, and on the 24th headquarters and other squadrons also moved to Le Cateau. 'We slept,' says Major Maurice Baring, 'and when I say we I mean dozens of pilots, fully dressed in a barn, on the top of, and underneath, an enormous load of straw.... Everybody was quite cheerful, especially the pilots.' On the afternoon of the 25th they moved again to St.-Quentin. The rapidity of the retreat put a heavy strain upon the headquarters of the Royal Flying Corps, which had to travel before the retreating army, to select an old aerodrome or to make a new one almost every day, and in the brief hours between arrival and departure to carry on all the complicated and delicate business of ministering to the needs of the squadrons. The places occupied by headquarters during the retreat were as follows:

MOVEMENTS OF THE ROYAL FLYING CORPS FROM AUG. 16th to OCT. 12th 1914.

In some of these places regular aerodromes were available, in others a landing-ground had to be improvised. Sometimes officers of headquarters would be sent on a long way ahead in motor-cars to select a landing-ground, while another officer in a motor-car was detailed to guide the transport. This he did by taking with him a small number of men and dropping them one by one at the partings of the ways. When the route was very complicated, these guides became so many that they had to be carried in a transport lorry. The transport drivers were not as yet skilled in the art of map-reading, and to lose the transport would have left the Flying Corps helpless. Sometimes the officers who selected the landing-ground moved with the transport, and made their choice when the transport reached its destination. The only recognized French aerodromes which were used by the Royal Flying Corps during the retreat were those at Compiègne, Senlis, and Melun.

Whilst the aerodromes were changing almost daily, the officers carried on reconnaissance, sometimes starting out not knowing whether their aerodrome would be in British or enemy hands by the time they should return. On the 24th, whilst the squadrons were moving from Maubeuge to Le Cateau, the enemy advance as seen from the air looked menacing enough. Captain G. S. Shephard and Lieutenant I. M. Bonham-Carter were watching von Kluck's right wing soon after 4.0 a.m. They returned at six o'clock with news of extensive movement about Ath and Leuze. They reported a broken column nearly ten miles long with its head pointing at Peruwelz. The column branched off the main Ath-Tournai road at Leuze. This was part of von Kluck's Second Corps, and its line of march would take it to the west of the extreme western flank of the British army. The news was not reassuring. Captain H. C. Jackson as observer with Lieutenant E. L. Conran went up at 8.30 a.m. and came back at 12.30 p.m. with information of long enemy columns moving from Grammont through Lessines into La Hamaide and further troops on the Ath-Leuze road. They had flown as far as Ninove and Alost, but found the country there clear. On returning over Lessines at 11.30 a.m. they saw three German aeroplanes on the ground; they dropped a bomb overboard, but missed.