There was very little room to move about. Most of the interior was occupied by the powerful motors and fuel-tanks, six-pounder guns mounted _en barbette_, and machine-guns, to say nothing of fifteen men of the original crew. The tank was in reality a moving magazine, for, in addition to the large quantity of petrol and ammunition, she carried a stock of phosphorous-bombs, smoke-bombs, and gun-cotton. The latter explosive was for use in the event of the tank becoming disabled and in danger of falling into the hands of the enemy, and it was the duty of the last surviving member of the crew to blow the land-ship to bits should there be a danger of capture. Derek, not content to be a mere passenger, looked around for something to do. The commander of the tank was too busy to notice the new arrival. His sole attention was directed towards the enemy through the periscope sights in the roof of the mastodon. An unattended machine-gun attracted Derek's notice. A brief examination showed that the mechanism was intact. There was ammunition in plenty. A neatly-punched hole just above the sighting-aperture told its own tale. An anti-tank bullet had passed through the armour, and had hit the machine-gunner fairly in the centre of his forehead. The tank was now lurching forward. Machine-gun bullets were splaying against its nose and sides. Fragments of nickel were forcing their way through the joints in the metallic beast's armour, and a sliver, cutting Derek in the cheek, gave him warning that he was not properly equipped for the task. Discarding his triplex glass goggles he donned a "tin hat" and steel visor that were lying on the floor. They had been the property of the dead machine-gunner, and had he been wearing them it is just possible that the anti-tank bullet that had laid him out might have glanced from the convex surface of the steel helmet. By this time the tank had skirted the edge of the crater and was bearing down upon a nest of Hun machine-guns. Even as it passed what appeared to be a pile of rubble an anti-tank gun was fired at a range of less than forty yards. Derek felt the windage of the missile as it passed completely through the armoured sides. Fragments of copper and steel rattled against his visor. Bending over the sights of his machine-gun, Derek prepared to deluge the concealed Huns under a hail of nickel, but before he could open fire the tank made a half-turn almost in its own length and went straight for the snipers' lair. The Huns saw it coming and promptly bolted. They had but two choices: one was to hold their ground and risk being pulverized under the banded wheels of the tank; the other to risk being shot down in the open. Bending low they ran. Few covered more than twenty yards, for the British machine-gunners were taking a heavy toll. Enfiladed by other tanks, the anti-tank gunners were completely wiped out with less compunction than if they had been rabbits in a warren.