Lawrence was fortunately cool of head and a rapid thinker. After a moment of stupefaction he saw his course clearly. The danger from the air must be met in the air. This could only be done by rising above the enemy's monoplane, and hurling his bombs down upon it. The Kalmuck pilot would be as anxious as he to avoid an actual collision, which must prove disastrous to both the machines. It was wholly a question of manoeuvring for position.
The glimpse he had caught of the hostile aeroplane as it flashed by, suggested that it was a much larger and more powerful machine than his own. If this were indeed the case, he was probably quite outmatched in speed as in armament. But he saw in a moment that the possession of the smaller machine might tend to his own advantage, for he could wheel in narrow parts of the valley where the attempt would prove destructive to the enemy. Moreover, he knew the valley thoroughly; the others, though no doubt vastly superior to him in a military sense, lacked local experience and had everything to learn. Time was on his side.
As soon as he began his flight he knew that he had gained one point. If the enemy had turned at his customary wheeling-place, their aeroplane would already have been in sight. The next suitable spot was several miles farther up the valley, unless indeed they should rise to a much greater height than that at which they had passed. Such an ascension would consume time; it would further make it very difficult for them to drop their bombs with any degree of accuracy. Whether they rose or continued their flight at the same altitude until they reached the wider turning-place, they would not be back for four or five minutes. Lawrence resolved to utilise this breathing space.
He flew on until he reached his usual turning-place, then began to mount in a spiral course. While he was doing this, two considerations flashed through his mind. If, when he met the enemy, he should be still below them, he must fly on in the opposite direction, for the chance of being hit by a bomb, when the machines were passing at the rate of perhaps a hundred and fifty miles an hour, would be very slight. His only fear in that case was that they would fly straight back to the mine and work havoc there without a possibility of interference. If, on the other hand, he were above them, his best course would be to fly in the same direction, and try to drop his bombs on them. When two express trains are running the same way, it is possible, however great their speed, to cast an object from a carriage of one through an open window of the other.
He was still ascending when Fazl shouted that the enemy's aeroplane was in sight, at a greater height.
"Rifle!" said Lawrence instantly, as he headed up the valley.
The Gurkha fired, as the two machines rushed at terrific speed towards each other. There was no reply, but a few seconds afterwards an explosion in the valley below showed that the enemy had dropped a bomb. It would have been almost a miracle if it had hit the aeroplane in the fraction of a second of the passing. But a second explosion a little later was very perturbing. Unless he could check the enemy, they might sail over the mine again and again, and on the wider target which that presented take surer aim. Luckily they would have to fly several miles down the river before they could again turn, and the few minutes' grace might give him time to ascend still higher, and attain an altitude at which he would have the advantage.
As the machines passed, Lawrence had had time to confirm his impression that the other aeroplane was much larger than his own. He saw too that it was occupied by three men. But these elements of superiority would be to some extent neutralized by the greater handiness of his own machine in navigating the narrow gorges of the valley. The situation demanded a readiness to take risks. The gorge to which Lawrence had now come after passing the enemy was so constricted that in ordinary circumstances he would never have dreamed of attempting a turning movement. But he felt the supreme necessity of wheeling at once, in order to return to the "bay" which he had lately left. There he might do something to protect the mine, if only by diverting the enemy's attack upon himself. He might also have an opportunity of rising to a sufficient height for offensive purposes.
Choosing the widest part of the gorge, he banked his machine up, and clearing the cliff apparently by inches he swept round again to the north. When in half a minute he reached the turning place, the aeroplane was not in sight. But he heard sounds of a fierce struggle beyond. The bombardment had ceased, but the air was filled with the crack of rifles, the rattle of the machine gun, and the shouts of men. He could do nothing to help his brother. There was not even time to fly on and drop a bomb among the enemy: he must utilise every moment in preparing for the return of the aeroplane. He steered his machine in a series of short spirals, rising as rapidly as possible, watching the valley northward anxiously. As yet its windings concealed the enemy's aeroplane from view. It was an inexpressible relief to him that they had not attempted to turn at the spot where he now was. They had not thought it practicable, or not had the time; probably they had shot by before even the possibility had occurred to them.
He swept round and round in his corkscrew flight, rising gradually until he was more than two thousand feet above the river. His view was now greatly extended, and when the larger aeroplane came in sight from round a bend nearly a mile away, he saw with a flash of hope that it was now lower than his own machine, although somewhat higher than before. Evidently the airmen had foreseen that he might rise in order to avoid their bombs, and sought to forestall him; but his narrow spiral had carried him up to a greater height than their two long inclined planes.