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THE MOLOKAI GARDENS OF CORAL. 175
THE CORAL MASONRY AND CORALS OF MOLOKAI AND OTHER
"There, in the furthest deserts of the Deep,
Ciirions work of Zoophytes—Sub-marine gardens described—Living specimens exhibited—Letting a crab out of prison—How the corals grow—Theory for the formation of a coral island—The tumuli of a buried continent—Evidence of a re-elevatory process—Geological phenomena not accounted for—Observations of Williams, the martyr of Eromanga—Effect of electricity in precipitating the particles of lime in sea-water—Instances adduced—The part it may have in the formation of reefsViews of Sir David Brewster examined—Mixture of fancy and fact—Experiments of Peyronnel—Philosophical analysis—Secrets of Nature's laboratory—Results of coral architecture—Astonishing amount of matter solidified—Observations of Captain Flinders—Conditions necessary to the perfection of coral—The coral builders watched —Work described—Banks reared—World-matter—Half-way Island—Coral formations of Rimatara—Honolulu reef—Mediterranean and Red Sea coral—Rate of growth—Effect of light—Agents that reduce it—Indian Ocean coral—Appearance of a reef between the tides—Millions of worms observed—Facts gathered from navigators—Coral of prose and of poetry—Moss corals by the microscope— Zoophytic tribes classified by the Geologist of the U. S. Exploring Squadron—Scientific deductions—Fejee Island reefs described—Vast size of individual specimens—Notices of the Kingsniill group—Vast depth of soundings off the reef—Uses of coral—Natural and aesthetic ends served.
The island of Molokai is well worth a traveller's visiting, despite the risk of crossing that boisterous channel, for the curious and beautiful corals he may get there, and the near view he may have of the living coral-beds, in all their sub-marine luxuriancy. You may go out upon the reef in a canoe, and sail over the gay gardens, and in only a foot or two of water, may gather some of the most exquisite specimens of marine animalculic vegetation ever seen.
The kinds, too, are uncommonly unique and various. In one mass, and disengaged at a single reach and effort of the arm, there will sqmetimes be five or six different species of this wonderful formation cemented together.
The colors are various, and sometimes exquisite. Now and then you can point out a piece to a native, and he will bring it up all blushing with purple or blue, which you would give any thing to preserve in a cabinet with that delicate Tyrian tint. Sometimes it is like colored confectionery crystallized, with all the hues of the rainbow. But the tints of sunset clouds are not more fading and evanescent than the rosy blush of those beautiful sea-flowers, when once plucked from their aqueous bed.
. It is only the coralline forms, or the different ways in which those ingenious little architects make their coral groves to grow, that can be preserved. And then those little radiations and branches are so brittle, and the microscopic finish of the crystalline structure is sometimes so nice, that in washing off the extraneous matters, and packing them up for friends at home, you are almost sure to break and mar the most perfect specimens.
It is very curious to observe how a family of corals will grow together and intermarry, till you can trace the pedigree from sire to son, through a coral ancestry for many generations. There is a species which the natives call ana, of which one of the missionary boys REMARKABLE SPECIMENS DESCRIBED.
here has a rare specimen to send to one of his brothers in America.
The ana grows somewhat like the head of a mushroom, on a flower-stalk put forth from the parent stock. If you call it a flower, its petals are innumerable white scales, growing erect, and separate each from its bed like the seeds of a sun-flower. These are of all sizes, from that of a button to the crown of a hat. The specimen referred to is a family tree, the trunk bearing its infant and youthful sprigs, of appropriate sizes through adolescence to maturity, when some of the adult anas are having little miniature grandsons of the third generation.
The theory which avers that corals do not grow vigorously in less water than two or three fathoms, is quite disproved by the growth at Molokai. We have seen and collected some fine living specimens, where the water was not more than two feet deep, and where the reef must be sometimes laid bare in low water.
In a specimen obtained by Mr. Andrews, only a few days ago, there was found snugly inclosed in one of the cups formed by the little branches locking in with each other like locked hands, an interloping crab. There he was, nicely caught and encased by the growing coral, as between the palms of two locked hands, precisely as toads are sometimes found in rocks, or the solid heart of trees. How long he had been imprisoned there by the busy little builders upon those immense reefs, we could not tell; but the boys thought it must have been in some Rip Van Winkle sleep, if such things ever happen in the life of crabs.
Coral is most abundant on the leeward of the Islands, and the larger reefs are only found there. It is said to be ascertained by observation, that a uniform temperature of at least seventy-six degrees is most favorable to their growth. The great thickness of the reefs is supposed to be caused by the gradual and long-continued subsidence of the original shelf of coral, while the surface is maintained at the same level as at first by the unceasing additions made by the polypes.
According to this theory, the islands of Polynesia once formed a vast equatorial continent, which, through volcanic agency as its probable cause, has subsided, and left the present islands as grave-stones to commemorate its former existence.
Be this as it may, besides the overflow from volcanic eruptions, a re-elevatory process must have been going on for ages in the islands of Hawaii, in order to account for the existence of well-defined coral, on this island of Molokai, for instance, five hundred feet above the present level of the sea.
The same has been found, also, according to Mr. Andrews, on Maui; and natives say that on one of the mountains of Kauai, four thousand feet above the sea, there is a bed of coral and coral sand, and in it a spring of water.
On the road from Lahaina to Wailuku, there is lava three or four hundred feet above the sea, covered with a deposit of lime from one-eighth to half an inch in PECULIAR FORMATIONS NOT ACCOUNTED FOR. 179
thickness, as if made by successive coats of whitewash, precisely as I have frequently seen stones at the seaside coated with carbonate of lime, which is, undoubtedly, a precipitate from the sea-water.
In ravines, and on the sides of precipices where the strata of successive volcanic eruptions are broken off, there is often to be found a perpendicular vein of carbonate of lime, that seems to have run into fissures, or to have been deposited there when in a state of solution, from what source it is not easy to tell. That it is lime cannot be doubted, for I have frequently seen it effervesce at pouring on sulphuric acid. There is also, on this island, one thousand feet above the sea, a locality of a mineral, very like to white flint, and which one might suppose to be crystallized coral, though it will not effervesce with the strongest acids.
While on the subject of corals, it is in place to mention an inference which Williams makes in his Missionary Enterprises, in regard to the formation of corals, from the fact of their being carbonate of lime always in solution with salt water. His remarks are, that, "as corals are carbonate of lime, and as they are found to exist only in warm climates, where, by the process of evaporation, there is abundance of materials supplied for these insects to build with, instead of secreting the substance, or producing it in any other way, they are merely the wonderful architects which nature employs to mould and fashion the material into the various and beautiful forms which the God of nature designed it