| 4.2 p.m. | A very little short. Fire. Fire. |
| 4.4 p.m. | Fire again. Fire again. |
| 4.12 p.m. | A little short; line O.K. |
| 4.15 p.m. | Short. Over, over and a little left. |
| 4.20 p.m. | You were just between two batteries. Search two hundred yards each side of your last shot. Range O.K. |
| 4.22 p.m. | You have them. |
| 4.26 p.m. | Hit. Hit. Hit. |
| 4.32 p.m. | About 50 yards short and to the right. |
| 4.37 p.m. | Your last shot in the middle of 3 batteries in action; search all round within 300 yards of your last shot and you have them. |
| 4.42 p.m. | I am coming home now. |
The later signals directing artillery fire were not so full of colour as these early messages. They consisted of code letters. The clock code for signalling the results of artillery fire was first used in 1915 and afterwards generally throughout the war. The target was taken as the centre of a clock and imaginary lines were circumscribed around it at distances of 10, 25, 50, 100, 200, 300, 400, and 500 yards. These lines were lettered Y, Z, A, B, C, D, E, F, respectively. Twelve o'clock was always taken as true north from the target and the remaining hours accordingly. An observer noted the fall of the rounds with reference to the imaginary circles and clock-hours and signalled the result, for instance, as Y 4, or C 6. A direct hit was O.K, and there were other signals. Messages from the battery or any other ground station were signalled to the observer in the aeroplane by means of white strips which were laid out on the ground to form the letters of a code.
During the battle of the Aisne, the wireless machines were few in number and other methods of signalling were mostly in use. On the 15th of September Captain L. E. O. Charlton fired Very lights over enemy guns previously observed. On the 24th of September 'Lieutenant Allen and two others with aeroplanes indicated targets and observed fire, communication being by flash signals'. Sometimes the pilots returned and landed to report on gun positions. But when once the gunners had profited by the superior accuracy and speed of report by wireless, they were hungry for more machines. On the 23rd of September the commander of the Second Corps telegraphed to General Headquarters: 'I hope that you will be able to spare the wireless aeroplane and receiving set to Third Division again to-morrow. The results were so good yesterday that it seems a pity not to keep it with the Division, which has got accustomed to its uses and is in a position to benefit even more largely by the experience gained.' The answer was that the machine had been damaged by anti-aircraft fire, but would be ready again shortly. A wireless aeroplane was as popular as an opera-singer, and the headquarters wireless section soon developed into No. 9 Squadron of the Royal Flying Corps. The attitude of the gunners may be well seen in an entry made in the war diary of No. 3 Siege Battery, dated the 23rd of January 1915—'Airman' (Captain Cherry) 'reported for co-operation (lamp only, alas!).'
The photography was a mere beginning. On the 15th of September Lieutenant G. F. Pretyman took five photographs of the enemy positions; these were developed later on the ground, and were the forerunners of that immense photographic map of the western front in thousands of sections, constantly renewed and corrected, which played so great a part in the later stages of the war. Some other experiments had no later history. Steel darts called 'flêchettes', about five inches long and three-eighths of an inch in diameter, were dropped over enemy horse-lines and troops by No. 3 Squadron. A canister holding about 250 of these darts was fixed under the fuselage; by the pulling of a wire the bottom of the tin was opened and the darts were released. To do any harm these darts had to score a direct hit on some living object, so that a whole canister of them was probably a less formidable weapon than a bomb. Even on a battle-field life is sparsely distributed on the ground.
There was hardly any fighting in the air during the battle of the Aisne, and reconnaissance machines were not attacked by other aeroplanes. They were fired at from the ground by anti-aircraft artillery. The anti-aircraft guns got their name of 'Archies' from a light-hearted British pilot, who when he was fired at in the air quoted a popular music-hall refrain—'Archibald, certainly not!' The Germans used kite balloons for observation. In the attempt to drop a bomb on one of these Lieutenant G. W. Mapplebeck was attacked, on the 22nd of September, by a German Albatross, and was wounded in the leg. He was the first of our pilots to be wounded in the air from an enemy aeroplane—a long list it was to be.
The Royal Flying Corps were few indeed in comparison with the air forces opposed to them, but they were full of zeal and initiative. On the 19th of September they received a valued compliment from the French General Staff, who asked the British Commander-in-Chief to permit them to carry out reconnaissances along the front of the Fifth French Army. This was already being done, but Sir David Henderson promised to take measures to make the reconnaissance more complete.
In the battle of the Aisne the British forces were co-operating with General Maunoury's Sixth French Army on their left. The so-called race for the sea was, in fact, a race for the flank of the opposing army. On the 20th of September De Castelnau's army formed up on the left of Maunoury and at first made some progress, but was pushed back by the reinforced army of General von Bülow, and was held on a line extending from Ribecourt on the Oise to Albert. On the 30th of September General Maud'huy's army came into position on the left of De Castelnau, along a line extending from Albert to Lens, while at the same time cavalry and territorials occupied Lille and Douai on the German right. This army in its turn was opposed by the German Sixth Army sent up from Metz, which pushed the French behind Arras, occupied Lens and Douai, and began to shell Lille. General Maud'huy could do no more than fight to hold his ground till another army should come to his relief on his left. For this purpose the British army was shifted from the Aisne to its natural position in defence of the Channel ports, and came into action along a line extending northwards from La Bassée. The actual line was fixed by a series of fierce engagements culminating in the battles of Ypres, 1914.
The Allied plan was to hold the French and Belgian coast and to take the offensive in the north. With this purpose in view the Seventh Division of the British army and the Third Cavalry Division, both of which came under the command of Sir Henry Rawlinson, were disembarked, from the 6th of October onward, at Zeebrugge and Ostend. But Antwerp was taken by the Germans on the 9th of October, and the first business of this famous force was to cover the Belgian retreat along the coast. The German Fourth Army was being rapidly pushed forward into Belgium; Lille capitulated on the 13th of October; Zeebrugge and Ostend were occupied by the Germans on the 15th. Still the idea of a counter-offensive was not abandoned, and the works and defences of Zeebrugge were left intact in the hope of its speedy recapture. On the night of the 1st of October the British army had begun to move northwards from the Aisne. By the 9th of October the British Second Corps had detrained at Abbeville and received orders to march on Béthune; on the 12th the Third Corps began detraining and concentrating at St.-Omer and Hazebrouck, and subsequently moved up to Bailleul and Armentières. A week later, on the 19th, the First Corps under Sir Douglas Haig detrained at Hazebrouck and moved on Ypres. General Headquarters left Fère-en-Tardenois on the 8th of October and after a five-days' stay at Abbeville established themselves at St.-Omer.
The Royal Flying Corps had moved north with the British Expeditionary Force, from Fère-en-Tardenois by way of Abbeville, to St.-Omer, where they were established by the 12th of October. No. 2 Squadron remained behind for a few days, to carry on with Sir Douglas Haig's corps on the Aisne, but joined up at St.-Omer on the 17th of October. In addition to the four original squadrons, No. 6 Squadron, newly arrived from England under Major J. H. W. Becke, came under Brigadier-General Henderson's orders on the 16th of October. This squadron had been stationed at South Farnborough as a reserve for the squadrons in the field. When General Rawlinson's force was sent to Ostend, to attempt the relief of Antwerp, Lord Kitchener said, 'I want a squadron to go with it'. He ordered that No. 6 Squadron should be ready in forty-eight hours. The squadron was hastily completed; some pilots and machines were obtained from the Central Flying School; some machines were bought from private firms; equipment, tools, and the like were collected at night; and on the 7th of October the squadron flew to Bruges and began at once to carry out reconnaissances. On the following day they flew to Ostend, and, their transport having arrived, were concentrated on the racecourse. Five days later they retired to Dunkirk, and by the 16th of October were established at Poperinghe, where they came under the orders of headquarters at St.-Omer.
A good deal of reconnaissance was carried on by the squadrons during the northward move of the army. On the 29th of September unusual and heavy movement in a northerly and north-westerly direction had been observed behind the enemy lines on the Aisne. On the 1st of October air reconnaissances showed that the trenches in front of the British First Army Corps were unoccupied or very lightly held, and during the next few days there were many indications that one or two German army corps were being withdrawn to the north. Meantime the enemy took more trouble than usual to interfere with our aircraft, and employed an increased number of anti-aircraft guns. In the north our strategic reconnaissances were not so successful, and the formidable enemy movement against the Ypres line developed undetected. Not many aeroplanes were available at this time for the wider sort of strategic reconnaissance. Nos. 2, 3, and 5 Squadrons had been attached, by an order issued on the 1st of October, to the First, Second, and Third Army Corps respectively, while No. 4 Squadron was detailed for strategical reconnaissance. The General Officers Commanding army corps had learned the value of aeroplanes and demanded their assistance. Much of the country over which they were operating in Northern France and Flanders was flat and enclosed, unsuitable either way for cavalry reconnaissance.