Then, in answer to a question from his companion, Vince shook off his fit of thoughtfulness, and sat chatting about the various objects they saw, principally about the caves they passed, some of which were low, arched places, excavated by the sea, whose entrances now stood out clear, now were covered by a wave which came back foaming from the compressed air it had shut-in.

Then the conversation turned upon the birds, familiar enough to them, but always fresh and new.

All along the face of these vast cliffs, and upon the outlying rocks, was a grand place for the study of sea-fowl.

They were quite unmolested, save at nesting-time, and then interfered with but little.

This was one of their strongholds, and, as the boat glided along back, the two lads set themselves to see how many kinds they passed.