Another explosion followed and then two more. The flight-sub felt the wall of the house rock with the concussions. He was quite prepared to see the building collapse under the impact of the displaced air. Fragments of slates and tiles, mingled with shattered woodwork, hurtled overhead. Glass tinkled upon the setts. The rumble of falling masonry was added to the uproar, while flames shot up from a mound of debris that a brief instant earlier had been the homes of three English families, and threw a fitful glare upon the scene of destruction. "Factory explosion, I suppose," thought Barcroft. "Can't be a Zep., or I should have heard her engines." He put his hand to his cheek. It was warm and moist. Blood was welling from a deep gash. He hardly noticed it. His attention was attracted by the shouts and screams of the terrified inhabitants of the neighbourhood--those whose houses having escaped annihilation but were within the danger zone, had fled pell-mell into the streets. Other crashes followed, but at a greater distance. "Then it is a Zep., by Jove!" declared the young officer. For the first time he realised his helplessness. He was virtually one of the thousands of civilians unable to raise a hand in self-defence against the cowardly night-raider. A Tommy in a trench with only a rifle--an almost useless weapon against an aircraft of any description--has the satisfaction that he is armed. He is willing to take his chance. But here the townsfolk were utterly at a loss to defend themselves, and it was sorry consolation to be told by the authorities that the inhabitants of raided districts are only sharing the dangers to which the troops in the trenches are exposed. "If only I were up aloft with young Kirkwood," thought Barcroft. "We'd make the beggars skip out of that gas-bag. Perhaps some day--" A woman, with her shawl wrapped tightly round her head, came hurrying in the opposite direction to which the stream of terrified people forced its way. "Eh!" she exclaimed. "An' I left t'owld mon's supper on t' stove. I'll be fair angry if 'tis spoilt." It was genuine anxiety. Even in the midst of the scene of destruction her thoughts dwelt upon the little cares of everyday domesticity. With the sailor's typical eagerness to render aid Barcroft hurried down the street. Already the ebb-tide of fugitives was thinning and giving place to the flood-tide of willing helpers. Here and there men staggered and groaned, bleeding from serious wounds caused by the flying fragments of the deadly missiles. Here and there came others supporting or carrying victims unable to help themselves-- stalwart men, frail women and puny children reduced in the fraction of a second to mangled wrecks. Pungent, asphyxiating fumes drifted slowly down the narrow thoroughfare, while the glare of the burning buildings threw an eerie light upon the surroundings.