Other prisoners, on being interrogated, testified to the awful effects of our fire. Upon one in particular, an artillery officer, was found an order that revealed the secret of the ineffectiveness of the enemy's reply. After briefly setting out the measures to be taken in case of a British offensive, it goes on as follows: "Owing to the fact that the preponderance of hostile artillery in this sector is probably more than two to one, and owing to the vital necessity of economy in ammunition, battery commanders will confine their fire to targets whose importance is known to them, and upon which they can count on producing a good effect. They will under no circumstances allow themselves to be drawn into anything approaching to an artillery duel." It was also stated by many captured officers that during the night September 23-24 a deserter from our line had conveyed to the German Staff the time and date of the coming assault, and that to this fact they owed much of the effectiveness of the measures taken to resist it. Yet another captured document was of somewhat disconcerting interest to us gunners, namely, a map upon which was very accurately shown the position of every allied battery, with only two exceptions, in the whole of our sector. It seems fairly certain that this was due to the most efficient espionage, and not to aerial observation. The material effect of such a bombardment is harder to judge, for it must be remembered that, despite the high science of modern gunnery, the percentage of direct hits upon a given objective is still comparatively small. When, however, a heavy shell detonates under favourable conditions, its destructive power is enormous. For instance, on the third day I saw a direct hit by one of our largest howitzers upon the boiler-house of Puits XVI. The shell penetrated the roof and burst inside the building, sending up an enormous cloud of black smoke tinged with the pink of pulverized brick, that hung for several minutes. When it cleared, nothing but a gaunt and twisted framework of steel girders remained, a heap of rubbish alone showing where the walls had stood. A smaller howitzer was ordered to fell a brick wall, some thirty feet high and many courses thick. The shell burst in regular sequence at its foot, at roughly ten yards interval, each round bringing down an equivalent section of the wall, until nothing remained but a long pile of smoking rubble. And, more impressive, perhaps, than all is the sight of a medium lyddite shell bursting in a narrow trench. Out of the centre of a vivid flash fly heavy timbers, sandbags, revetments, all that once formed the trench, sometimes the mangled fragments of its occupants, whilst to right and left rolls the choking smoke, driving its way into the deepest dug-outs, overcoming men many yards away from the point of impact, spreading death in every form. Is it to be wondered at that when our infantry reached these trenches they