"Right-o, Jock! Throw out the signal-Zeppelin."
And the next moment a couple of smoke bombs were thrown out by the observer, which gave the order, "Prepare to attack."
"Whir-r-r!" went the four 'planes on their new tack, as the controlling wires went over, and each machine banked suddenly and came round head on towards the enemy.
"By Jove, she's seen us and she's heading off too!" shouted Jock through the tube.
"Yes, so I see. Bet she's using her wireless some to call for the Fokkers. We haven't much time to lose."
In less than three minutes they were within machine-gun fire of the huge gas-bag, which was flying as low as three thousand feet, and seemed incapable of lifting herself much, either through shortage of gas or damaged machinery.
"Look out! She's opening fire! See there!" Short sharp jets of fire spat out from the gondolas of the Zeppelin in half a dozen different places, and the bullets began to whistle and ping-ping about the ears of the aviators.
"Reserve your fire, boys!" ordered Dastral, for he knew that they would all be anxious to fire. Then he threw out another order, which meant, "Attack from above."
This they all understood immediately, and followed Dastral as he made his machine almost sit upon her tail, as she climbed and manoeuvred to get above the huge lumbering mass, which was already levering away to leeward on account of some defective machinery, and the fresh breeze which had sprung up from the south-east.
Two minutes later they were almost directly above the Zeppelin, and, except for two machine-guns which were mounted above the envelope, they were immune from fire, for the other guns down below were screened by the huge looming mass above them.