In the credit for this result the first place must be given to the efficiency of British leadership, which was admirable in its perseverance and in its general conception, but had, it must be admitted, not yet attained that skill in the avoidance of losses which was gradually taught by our terrible experiences and made possible by our growing strength in artillery. The severe preliminary bombardment controlled by the direct observation which is only possible after air supremacy has been attained, the counter-battery work to reduce the enemy's fire, the creeping barrage to cover the infantry, the discipline and courage which enable infantry to advance with shrapnel upon their very toes, the use of smoke clouds against flank fire, the swift advance of the barrage when a trench has fallen so as to head off fugitives and stifle the counter-attack, all these devices were constantly improving with practice, until in the arts of attack the British Army stood ahead even of their comrades of France. An intercepted communication in the shape of a {308} report from General von Arnim, commanding the Fourth German Army, giving his experience of the prolonged battle, speaks of British military efficiency in every arm in a manner which must have surprised the General Staff if they were really of opinion that General Haig's army was capable of defence but not of attack. This report, with its account of the dash and tenacity of the British infantry and of the efficiency of its munitions, is as handsome a testimonial as one adversary ever paid to another, and might be called magnanimous were it not that it was meant for no eye save that of his superiors.