A curious feature of this strange siege-battle was that villages and hamlets between the fighting lines still continued, where not destroyed, to be in part, at any rate, inhabited, and at intervals peasants worked in the intervening fields. The Germans took advantage of this to push their spy system.
The suspicions of some French troops (of the 5th army) were aroused by coming across a farm from which the horses had not been removed. After some search they discovered a telephone which was connected by an underground cable with the German lines, and the owner of the farm paid the penalty usual in war for his treachery.
Some of the methods being employed for the collection or conveyance of intelligence were:—
Men in plain clothes who signalled to the German lines from points in the hands of the enemy by means of coloured lights at night and puffs of smoke from chimneys by day.
Pseudo-labourers working in the fields between the armies who conveyed information, and persons in plain clothes acting as advanced scouts.
German officers and soldiers in plain clothes or in French or British uniforms remained in localities evacuated by the Germans in order to furnish them with intelligence.
One spy of this kind was found by the British troops hidden in a church tower. His presence was only discovered through the erratic movements of the hands of the church clock, which he was using to signal to his friends by means of an improvised semaphore code.
Women spies were also caught, and secret agents found observing entrainments and detrainments.
Amongst the precautions taken by the British to guard against spying was the publication of the following notice:—
(1) Motor cars and bicycles other than those carrying soldiers in uniform may not circulate on the roads.
(2) Inhabitants may not leave the localities in which they reside between six p.m. and six a.m.
(3) Inhabitants may not quit their homes after eight p.m.
(4) No person may on any pretext pass through the British lines without an authorisation countersigned by a British officer.
On October 23rd six batteries of heavy howitzers asked for by Sir John French reached the front, and were at once put into action. No effort was spared by the Germans to drive the British army back across the Aisne. The quantity of heavy shells they fired was enormous, and they were probably under the impression that the effect was devastating.
The object of the great proportion of artillery the Germans employ (observes the official record on this point) is to beat down the resistance of their enemy by a concentrated and prolonged fire, and to shatter their nerve with high explosives before the infantry attack is launched. They seem to have relied on doing this with us; but they have not done so, though it has taken them several costly experiments to discover this fact. From the statements of prisoners, indeed, it appears that they have been greatly disappointed by the moral effect produced by their heavy guns, which, despite the actual losses inflicted, has not been at all commensurate with the colossal expenditure of ammunition, which has really been wasted.