Lawless was at the fore-end of the car, and almost in total darkness, for not only were the lights on deck masked, but the crew worked with electric torches which threw out only momentary gleams of light. Taking advantage of this, he began to work the cord which bound his wrists up and down against the sharp edges of the girder till at last he frayed the rope sufficiently to break it. This done, to remove the cords from his ankles was but the work of a moment, and then he stood free to act once more. For a time, however, he did not move, but stood as though still fettered, in order not to attract the attention of the crew till he had decided what to do. All at once everybody on board the dirigible was startled by the sound of guns in the distance, and next moment the sky was illuminated by searchlights which swept the horizon like tremendous phosphorescent antennæ. Mike had given the alarm! Several minutes elapsed before the searchlights found the airship and focused themselves upon it, and then everything on board was illuminated by the dazzling rays. A few seconds later the sound of firing increased, and Lawless guessed that a battery of howitzers was being trained on the dirigible. But as yet the distance was too great for the gunners to get the range, and he knew that, even when they did so, the guns fired at too low an angle to hit an object so high above them. Thanks to the brilliant illumination of the searchlights, he was able to see everything as though it were broad daylight, and, among other things, he noticed hand grenades placed at various points around the car. They were evidently provided for dropping on small objects or groups of men, where the use of a bomb would be unnecessary and wasteful. In a flash he had determined what to do. The dirigible was now within a mile of the Forth Bridge and about five hundred feet in the air. If the present speed were maintained, it would be directly over the bridge in less than five minutes. The howitzers had by now been supplemented by small groups of sharpshooters, but with the exception of a few stray bullets which occasionally whistled past the small-arm fire was likely to do as little damage as the heavier guns. It was clear that, unless some unforeseen accident occurred, the airship would accomplish her purpose. As they drew nearer a fresh burst of firing, this time from the bridge itself, showed that two guns had been dragged on to the railway track to command a better range of the approaching airship. But this attempt, like the rest, was in vain, for the shells flew harmlessly below the car, and, even had they been able to reach it, an ascent of fifty feet or so more would have placed the dirigible but of danger again. Only an anti-aircraft gun, firing at right angles to its base, could hit the terrible war machine above.