Advancing farther and farther to the south, the iceberg loses one after another the witnesses of its first migrations, and wasting more and more, at length entirely merges in the tepid Gulf Stream. The enthralled waters are now all liberated, but many on their western passage are again diverted to the north, and the others reach, only after a long circuit, the mighty equatorial stream, which carries them along, through the torrid ocean, from one hemisphere to the other. [Illustration: SPERM WHALE.] The animal life they meet with in these sunny regions is very different from that which witnessed their passage through the higher latitudes. The large whalebone whale, the rorqual and narwhal of the north, have disappeared, but _pods_ of the mighty sperm whale rapidly traverse the equatorial seas. The birds also exhibit new types of being. The royal albatross avoids the torrid zone, but the high-soaring frigate-bird hovers over the waters, where it is seen darting upon the flying-fish, and, like the skua gull of the north, attacking the weaker sea-birds in order to make them disgorge their prey. [Illustration: FRIGATE BIRD.] ‘He is almost always a constant attendant upon our fishermen,’ says Dr. Chamberlain,[24] ‘when pursuing their vocation on the sand-banks in Kingston Harbour, or near the Palisados. Over their heads it takes its aërial stand, and watches their motions with a patience and a perseverance the most exemplary. It is upon these occasions that the pelicans, the gulls, and other sea-birds become its associates and companions. These are also found watching with equal eagerness and anxiety the issue of the fishermen’s progress, attracted to the spot by the sea of living objects immediately beneath them. And then it is, when these men are making their last haul, and the finny tribe are fluttering and panting for life, that this voracious bird exhibits his fierce propensities. His hungry companions have scarcely secured their prey by the side of the fishermen’s canoes, when, with the lightning’s dart, they are pounced upon with such violence that, to escape his rapacious assaults they readily, in turn, yield their hard-earned booty to this formidable opponent. The lightness of its trunk, the short torso and vast spread of wing, together with its long slender and forked tail, all conspire to give it a superiority over its tribe, not only in length and rapidity of flight, but also in the power of maintaining itself, on outspread pinions, in the regions of its aërial habitations amidst the clouds; where, at times, so lofty are its soarings, that its figure becomes almost invisible to the spectator in this nether world.’