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. By this it is not implied that their artillery fire is not good. It is more than good; it is excellent. But the British soldier is a difficult person to impress or depress, even by immense shells filled with high explosive which detonate with terrific violence and form craters large enough to act as graves for five horses. How far the colossal expenditure of ammunition was thrown away is illustrated by this description of the effect in a given instance:--