She pointed away to the south-east. The crests of the distant hills were silhouetted against a succession of pale flashes and the glare of half a dozen searchlights, while the low rumble of a series of explosions could just be distinguished.
Then the flashes ceased, although the giant beams still searched the sky—and searched in vain. The huge target presented by the Zeppelin had been lost to sight.
"There's something overhead," declared Tressidar. "It's an aerial propeller, but for a Zepp. it's very subdued. You're not nervous, Doris?"
The girl smiled.
"Being nervous wouldn't be of any use, so I must be brave," she replied. "As a matter of fact I am rather enjoying the experience. Do you think——"
A lurid flash and terrific crash, the sound appearing to emanate from a spot within a hundred yards from where they waited, interrupted her words. The flash was followed by two others in quick succession, and then a perfect hail of high-explosive bombs. The Zepp. was hurling down missiles as fast as she could from a height of less than two thousand feet upon what her commander took to be the Sauchieblair Munition Works. In point of actual fact the bombs were dropping, thanks to Tressidar's resourcefulness in altering the position of the leading lights, on the grassland full a mile from the Huns' particular objective.
For nearly twenty minutes the futile operation of bomb-dropping continued. Once or twice the sub. turned to look at the shepherd. The man was gazing stolidly into the darkness with his back turned upon the German firework display. He had been set a particular task and whole-heartedly he was carrying it out.
At length, as if suspecting that they were being tricked, the crew of the Zeppelin ceased hurling explosives. They switched on two powerful searchlights, which, playing in an almost vertically downward direction, swept the ground in order to discover the magazine buildings. To do so the airship had dropped to less than a thousand feet.
"They'll find the place, I'm afraid," thought Tressidar. "If only our people had even a couple of anti-aircraft guns——"
The shepherd touched his arm and pointed down the road in the direction of Auldhaig. Approaching at a furious rate, their presence only apparent by the noise they made, were several motor-cars armed with quick-firers on vertical mountings. Others, with travelling searchlight projectors, accompanied them. The lights were temporarily screened, since the position of the hostile airship could be fixed by the fact that she was playing her searchlights upon the ground.