at first. But through the still, clear water the light filtered freely from below, showing the bottom as through a sea glass. We saw the fish near the entrance, and coral and sea growths of marvellous vividness. They waved slowly as in a draught of air. The medium in which they floated was absolutely invisible, for, of course, there were no reflections from its surface. We seemed to be suspended in mid-air, and only when the dipping oars made rings could we realise that anything sustained us.
Suddenly the place let loose in pandemonium. The most fiendish cries, groans, shrieks, broke out, confusing themselves so thoroughly with their own echoes that the volume of sound was continuous. Heavy splashes shook the water. The boat rocked. The invisible surface was broken into facets.
We shrank, terrified. From all about us glowed hundreds of eyes like coals of fire—on a level with us, above us, almost over our heads. Two by two the coals were extinguished.
Below us the bottom was clouded with black figures, darting rapidly like a school of minnows beneath a boat. They darkened the coral and the sands and the glistening sea growths just as a cloud temporarily darkens the landscape—only the occultations and brightenings succeeded each other much more swiftly.
We stared stupefied, our thinking power blurred by the incessent whirl of motion and noise.
Suddenly Thrackles laughed aloud.
"Seals!" he shouted through his trumpeted hands.
Our eyes were expanding to the twilight. We could make out the arch of the room, its shelves, and hol-
