It was a question of time, and the time must needs be brief. The bridge must go. Half way across, beneath the feet of the scrambling, sobbing crowd, the roadway split and cracked. There was a sudden lurch that sent Linton and Zenobia, with a dozen others, into the open doorway of a right-hand shop. Like all the rest of the bridge buildings, it was but one storey high, and at the end of the short passage a narrow stairway gave access through a trapdoor to the leads. Linton, breathing heavily from his exertions, gasping a few words of encouragement to Zenobia, pondered in a flash the possibilities of the position. Those who had been swept into the deserted shop with them were making frantic and futile efforts to force their way back into the endless crowd that still streamed across the bridge in such maddened haste. But a place once lost in that dense multitude never could be recovered. In truth, there was no choice, and in a moment his resolve was taken.

"The roof," he whispered, half to himself, "the roof!" Mounting the steps, he swept back the trapdoor, and, reaching down his hand, drew Zenobia after him. They emerged upon the flat roof of the shop. Only a dwarf party wall divided it from the rest.

Below, on their left, the rushing and tumbling tide of humanity pressed forward to the Bathwick side. Below, on their right, they beheld the terrifying river, curdled in foam and throwing off increasing clouds of heavy steam. They scrambled forward quickly, passing on from roof to roof. Behind them came the sudden sound of rending masonry. A dreadful scream, a wild cry of despair from the multitude, pierced the powdery air. The bridge was slowly yielding to the enormous pressure of the swollen river; but Linton and Zenobia had safely reached the other side. Raising the trap door of the last shop in the row they descended rapidly and gained the road. Here the congested throng spread out across the wider space, and hurried onward to Great Pulteney Street.

As they paused there came a sound—terrible, arresting, never-to-be-forgotten—the united wail of despairing voices, rising above the crash of the collapsing bridge as it carried with it, down into the boiling flood, hundreds of helpless and entangled fugitives. Zenobia, clinging convulsively to her protector, drew sobbing breaths at those appalling sounds. But for his supporting arms she would have sunk fainting to the ground.

"Courage," he whispered. "Courage still."

For the moment he himself believed that on this side of the river they were safe. But at that instant they felt again beneath their feet the quaking of the ground—a long and undulating throb. They reeled against a wall and stood there panting, until a quickened sense of peril impelled them once again to hasten forward. Turning up Edward Street, and leaving the church upon their left, they climbed the hill, until exhaustion compelled them to sink down upon a roadside bench and ease their labouring lungs.

Thick grey smoke, heavy with choking particles and powdery ashes, was spreading everywhere; and from this higher ground, looking back towards the fiery summit of the volcanic hill, they could see cloud after cloud of fire-torn vapour mounting with spiral motion towards the darkened heavens.

Wearied though they were, they struggled to their feet, and once more set their faces towards the hill. Linton fully realised that the area of disturbance was far wider than he had at first supposed. Safety, if attainable at all, could only be secured by placing many miles between themselves and the volcanic district. It was no time for weighing small considerations. Silently he decided what to do.

They reached the house in which the President had spent and ended the last days of his life. The hall door was wide open; darkness and silence reigned in the interior. The servants, obviously, had fled. Linton shouted, but no answer came. It was clear to him that the engineer of the Albatross was in full flight with the rest.

Bidding Zenobia rest a minute in the hall, he opened the glass doors on the inner side and ran down the steps into the garden. There lay the Albatross, ready, as he knew, for an immediate aerial journey. His own knowledge of the mechanism of an air-ship, though not complete, was now sufficient, or, at any rate, it must be trusted. The boat was rather smaller than the Bladud, and in some respects contained improvements. A swift examination of the machinery satisfied him that the Albatross was fit for flight.