"The atoll is another curious form of the work of the coral insect," said the Doctor, continuing. "It is circular or oval in shape, the island forming a rim that encloses a lake or lagoon. There is always an opening from the sea to the lagoon, and it is generally on the leeward side. Sometimes there are two, or even three or more openings, but this is unusual; the island rises only a few feet above the water, and is the work of the coral insect upon what was once the crater of a volcano; at least that is the general belief.
"The atoll is not a desirable place for residence, as the ocean during severe storms is liable to break across the narrow strip of land and sweep away whatever may be standing there. Many atolls are uninhabited, and none of them has a large population; cocoa-palms, bread-fruit, and other tropical trees are generally found on the inhabited atolls, and partially or wholly supply the natives with food. In some instances the people support themselves by fishing either in the lagoon or in the ocean outside. The lagoon forms a fairly good harbor for ships and canoes, but sometimes the water in it is too deep for anchoring."
As the minutes rolled on, the outlines of the mountains and ridges, the valleys and forests, grew more and more distinct. Frank and Fred strained their eyes to discover an opening in the reef, but for some time their earnest gaze was unrewarded. At length, however, Frank saw a spot where the long line of spray appeared to be broken; gradually it enlarged, and revealed a passage into the great encircling moat of Tahiti. It was the entrance to the harbor of Papéiti, the capital of the French possessions in this part of the Pacific.
[Illustration: ON THE SHORE OF THE LAGOON.]
The yacht glided safely through the channel and anchored in front of Papéiti, or Papaete, as some writers have it. Two French war-ships were lying there, and several schooners and other sailing-craft engaged in trade among the islands. Then there were some half-dozen ships and barks from various parts of the world, bringing cargoes of miscellaneous goods for the Tahitian market and carrying away the produce of the islands. Frank looked in vain for an ocean-going merchant steamer, and found, on inquiry, that the Society Islands are not visited by any of the steamships engaged in the navigation of the Pacific.