It was drawing towards evening when, just as Pariset had dropped his field-glasses with a gesture of annoyance, a messenger came running from the commandant to say that the Zeppelin had been sighted.
"How does he know?" asked Pariset, incredulously.
"He had word by field telephone," was the answer. "The airship is coming from the north-east."
Pariset instantly started his engine. But before the aeroplane was aloft, the airship appeared in the distant sky, like a torpedo of the air. There was a certain fascination in its swift and steady approach, growing bigger and bigger to the sight. Its course would bring it within half a mile of the portable sheds; perhaps its object was to destroy the Belgian aeroplanes.
Having a reasonable respect for the Zeppelin's machine guns, Pariset at first kept well away from its course. He bore to the east, so as to avoid a direct meeting with it, and to get between it and its base. That the aeroplane had already been seen from the airship, high above it, was proved by the smack of several bullets upon parts of its structure; but they had not heard the crackle of the rifles, what with the whirr of their engine and the incessant thunder of artillery.
Comparing notes afterwards, they agreed that their first impression was wonder at the speed and accuracy with which the Germans had got their range. Pariset at once flew off at a wider angle, trusting to his superior speed to carry him out of danger until he had had time to rise above the Zeppelin. He could climb only gradually, if he was to take full advantage of his speed. It was nearly ten minutes before Kenneth reported that they were about equal with it in height. The airship was now at least two miles astern, and had slightly altered its direction. Pariset now swung round. He guessed that the Zeppelin was making for Fort Loncin, probably to reconnoitre, for its bombs would have little or no effect on the armoured cupola of the fort. Flying back, he steered so as to approach the airship on its flank, and succeeded in his aim of showing the enemy that the aeroplane was to be reckoned with. It again altered its course; Pariset shifted his rudder also; and the Zeppelin gave chase.
Bullets whistled around the aeroplane, which by this time had risen several hundred feet higher than the enemy. Adjusting his planes to secure the maximum lift, Pariset began to climb steeply, and for some minutes the Zeppelin gained on him in horizontal direction. But the rapidity of his ascent rendered the task of its marksmen very difficult; and they seemed to realise that they were themselves in danger, for they altered their course, bearing to the east, as if they had abandoned the chase.
The parts were now reversed. The aeroplane became the hunter, the airship the hunted. Still rising, Pariset gradually reduced the horizontal distance between them, gaining assistance from the manoeuvres of the Zeppelin, which yawed now and again in order to bring its guns to bear more effectively, thus losing pace. The aeroplane began to close in with it, and Pariset suddenly became aware that he was closing in too rapidly, for the airship either stopped her engines or reduced their speed. Before he had time to meet the manoeuvre he had come within effective range. Bullets pattered around like hail, and only by a swift wheeling movement did he escape destruction.
Learning caution, he rose still higher, until he estimated that he was at least 3000 feet above the enemy. At this elevation the swelling bulk of the envelope rendered the machine guns useless, and there was indeed little chance of the aeroplane's being hit even by the rifles.
Pariset's object was now to get as nearly as possible vertically above the Zeppelin, which the Zeppelin could only prevent by constantly changing its course and its speed. But Pariset was an adept in the handling of his machine. He watched every twist and turn of the enemy, and seemed to Kenneth to anticipate them, as a skilful boxer anticipates the feints and rallies of his opponent.