Sometimes the clouds of smoke would be almost continuous, but these shell-bursts were not confined to the front lines. From where Tam hung he could see billowing smoke clouds appear in every direction. Far behind the enemy's lines at the great road junctions, in the low-roofed billeting villages, on the single-track railways, they came and went.
The thunder of his engines drowned all sound so he could not hear the never-ceasing booming of the guns, the never-ending crash of exploding shell. Once he saw a heavy German shell in the air—he glimpsed it at that culminating point of its trajectory where the shell begins to lose its initial velocity and turns earthward again. It was a curious experience, which many airmen have had, and quite understandable, since the howitzer shell rises to a tremendous height before it follows the descending curve of its flight.
He paid a visit to the only cloud that had any pretensions to being a cloud, and found nothing. So he went over the German lines. He passed far behind the fighting front and presently came above a certain confusion of ground which marked an advance depot. He pressed his foot twice on a lever and circled. Looking down he saw two red bursts of flame and a mass of smoke. He did not hear the explosions of the bombs he had loosed, because it was impossible to hear anything but the angry "Whar—r—r—!" of his engines.
A belligerent is very sensitive over the matter of bombed depots, and Tam, turning homeward, looked for the machines which would assuredly rise to intercept him. Already the Archies were banging away at him, and a fragment of shell had actually struck his fuselage. But he was not bothering about Archies. He did swerve toward a battery skilfully hidden behind a hayrick and drop two hopeful bombs, but he scarcely troubled to make an inspection of the result.
Then before him appeared his enemy. Tam had the sun at his back and secured a good view of the Müller machine. It was the great white dragon-fly he had seen two days before. Apparently Müller had other business on hand. He was passing across Tam's course diagonally—and he was climbing.
Tam grinned. He was also pushing upward, for he knew that his enemy, seemingly oblivious to his presence, had sighted him and was getting into position to attack. Tam's engine was running beautifully, he could feel a subtle resolution in the "pull" of it; it almost seemed that this thing of steel was possessed of a soul all its own. He was keeping level with the enemy, on a parallel course which enabled him to keep his eye upon the redoubtable fighter.
Then, without warning, the German banked over and headed straight for Tam, his machine-gun stuttering. Tam turned to meet him. They were less than half a mile from each other and were drawing together at the rate of two hundred miles an hour. There were, therefore, just ten seconds separating them. What maneuver Müller intended is not clear. He knew—and then he realized in a flash what Tam was after.
Round he went, rocking like a ship at sea. A bullet struck his wheel and sent the smashed wood flying. He nose-dived for his own lines and Tam glared down after him.