Careering towards them through the upper air, at what seemed lightning speed, was something which left a long, luminous trail behind it. Rays and flashes of light of different colours burst from it in its course, darting out in all directions. A low, rushing sound became audible, which quickly increased in volume until it became a terrific, deafening, overwhelming roar.
There was a sudden disturbance in the air, as of the approach of a whirlwind, and a crackling noise as of the discharge of fireworks.
Then something seemed to shoot past them into the sea, the 'wind' from it almost brushing them aside like that caused by a shell fired from some colossal cannon.
From the sea came a mighty crash as of a loud explosion, while columns of water and clouds of vapour rose into the air. The water came right over the top of the cliff, drenching the amazed spectators, and almost sweeping one—it was Jack—off his feet.
Hardly had the spray cleared away when there was another commotion in the water. The sea, boiling and chafing, seemed to rise up into a pyramid, and from it a huge dark mass shot up into the air, dropping back into the sea again with a plunge only a little less violent than that which had accompanied its first fall.
For a brief space it was lost to view, and then it reappeared, shooting again high into the air, as might a gigantic whale throwing itself out of the sea in sport or an endeavour to escape some terrible marine foe.
These mad leaps and plunges were repeated again and again, becoming each time less in height and violence, until at last they ceased.
It was some time, however, before the agitation in the water came to an end. Great waves rushed booming along the shore, dashing wildly up the face of the cliffs, sending clouds of spray flying over their summits far inland.
But after a while the commotion subsided, the sea became smooth on the surface, and there remained only a gentle heaving, as from a ground swell.
And there, at a little distance from the shore, the cause of all this disturbance was plainly to be seen—an immense, egg-shaped mass many hundreds of feet in length, floating as lightly and buoyantly upon the still-heaving water as if it had been an immense football.