When well clear of the Marquesas the Pera turned her prow to the south-west, in the direction of Tahiti, which lay about nine hundred miles away. The strong trade-wind bore her swiftly on her course, and on the fourth day of the voyage the lofty peaks of Otaheite's isle rose into view. The summits of the mountains seemed to pierce the sky, so sharp and steep were they, and almost to their very tops they were covered with verdure. Luxuriant forests were everywhere visible, and the shore was fringed with a dense growth of palms that seemed to rise from the water itself.
The central peak of Tahiti has an elevation of something more than seven thousand feet, and from this peak there is a series of ridges radiating towards the sea like the spokes of a wheel. Many of these ridges are so steep on their sides that they cannot be ascended, and so narrow that there is not room for an ordinary path. A man standing on one of these ridges could with his right hand throw a stone into one valley, and with his left a stone into another, whose inhabitants could communicate only by descending to the coast, or to the lowland which borders it. The valleys are luxuriant, and even the ridges are covered with vines and bushes.
As the youths, with their glasses, eagerly scanned the coast they were approaching, one of them called out that he could see a strip of calm water close to the shore.
"We are coming to the great barrier-reef of coral," said Doctor Bronson, "and the calm water that you see is between the reef and the shore.
SPECIMEN OF CORAL.
"Tahiti is one of the best examples of an island surrounded by a coral reef," the Doctor continued. "It extends quite around the island, sometimes only a few yards from it, and sometimes four or five miles distant. There are occasional openings through the reef, some wide and deep enough to permit the passage of large ships, and others practicable only for small boats. Inside the reef the water is calm, and a vessel once within it has a secure harbor."
The boys could see the surf breaking on the reef with great violence, and throwing spray high into the air. Outside was the ever-restless sea; inside lay the placid lagoon, which reflected the sunlight as in a mirror.