At some little distance behind the front line (a hundred yards or so) was a second fire line, wired like the first, though less elaborate and generally without concrete fortlets. This second line was usually as well sited for fire as the front line. There were many communication trenches between the two lines. Half a mile behind the second line was a third support line; and behind this, running along the whole front, a mile or more away, was the prepared second main position, which was in every way like the front line, with wire, concrete fortlets, dugouts, and a difficult glacis for the attacker to climb. The enemy batteries were generally placed behind banks or lynchets which gave good natural cover; but in many places he mounted guns in strong permanent emplacements, built up of timber balks, within a couple of miles (at Fricourt within a quarter of a mile) of his front line. In woods from the high trees of which he could have clear observation, as in the Bazentin, Bernafay, and Trones Woods, he had several of these emplacements, and also stout concrete fortlets for heavy single guns. All the enemy position on the battlefield was well gunned at the time of the beginning of the battle. In modern war, it is not possible to hide preparations for an attack on a wide front. Men have to be brought up, trenches have to be dug, the artillery has to prepare, and men, guns, and trenches have to be supplied with food, water, shells, sandbags, props, and revetments. When the fire on any sector increases tenfold, while the roads behind the lines are thronged with five times the normal traffic of troops and lorries, and new trenches, the attack or "jumping-off" trenches, are being dug in front of the line, a commander cannot fail to know that an attack is preparing. These preparations must be made and cannot be concealed from observers in the air or on the ground. The enemy knew very well that we were about to attack upon the Somme front, but did not know at which point to expect the main thrust. To be ready, in any case, he concentrated guns along the sector. It seems likely that he expected our attack to be an attempt to turn Bapaume by a thrust from the west, by Gommecourt, Puisieux, Grandcourt. In all this difficult sector his observations and arrangements for cross-fire were excellent. He concentrated a great artillery here (it is a legend among our men that he brought up a hundred batteries to defend Gommecourt alone). In this sector, and in one other place a little to the south of it, his barrage upon our trenches, before the battle, was very accurate, terrible, and deadly.