is small! It is such men as Wyllie to whom King and people and foreigners also still must look; and whilst their searching eyes glance round the horizon, their lips may prayerfully exclaim

EXORIARE ALIQUIS !

APPENDIX.

CORAL ISLANDS.

is the general assumption that coral islands are built up

lithophytes. Doubts of this fact have, however, been entertained and expressed. Captain Wilkes, who commanded the United States Exploring Expedition (1838–1842), has stated his decision, that coral islands cannot possibly be entirely the work of zoophytes. He pronounces the labours of these minute animalculæ inadequate to produce effects so enormous, and says that the appearance of the reefs themselves contradicts such a presumption; and he adds that Darwin's ingenious theory of an equal growth and subsidence of coral taking place is at variance alike with the configuration, extent, and general construction of the reefs. Darwin argues thus:-From the limited depth at which reef-building polypifers can flourish, one ought to conclude that both in atolls and barrier-reefs the foundation to which the coral primarily is attached has subsided, and that during the gradual depression of the base of the coral, reefs have grown upward. He says this will satisfactorily explain their outline, general form, and distribution; that the existence of reefs and islands dispersed in large tracts of ocean, which islands and reefs are formed by the growth of kinds of coral, the insects of which cannot live at great depths, is inexplicable, except on the theory that the base to which the reefs are first attached slowly and successively sinks whilst the corals grow upwards; that no positive facts are opposed to this view, &c. (Voyages of the Beagle.')

If we consider the stupendous workmanship required to

LL

upheave a reef hundreds of miles in length,-and such exist; that on the north-east coast of New Holland and New Caledonia extending four hundred miles,-or islands many hundred square miles in area, and believe the lithophytes' labour to be a sufficient cause, it requires a credulity as to Nature's workings such as commonly existed before the time of Bacon, and even that of Boyle, but which has since been rebuked by experimental philosophy. Soundings made by Beechey, Flinders, and others, show that depths of two and three hundred feet of water sometimes occur near the raised reef, within the enclosure of lagoonislands, whilst outside the depth is often unfathomable. Wilkes found no bottom with a line of 150 fathoms (900 feet) at that distance from the perpendicular cliffs of Aurora Island; and Dana says that within three-quarters of a mile from the southern point of the island of Clermont Tonnere, the lead brought up suddenly at 350 fathoms (2,100 feet) and then dropped off again and descended to 600 fathoms (3,600 feet) without reaching bottom. The lagoons within the circular reefs are, however, generally shallow in comparison, and a great depth inside is exceptional.

In the Indian Ocean and Coral Sea still deeper soundings have been made than those mentioned. Dr. Maury ('Physical Geography of the Sea ') quotes a letter from Mr. Brooke stating that the sounding-rod reached bottom in the Indian Ocean with a line of 7,040 fathoms (42,240 feet). It must, however, be observed that the length of line does not always express the perpendicular distance, as there is always a driftage of the line, sometimes a very great one. Maury mentions a specimen of the bed of the Coral Sea brought up with Brooke's soundingrod at a reported depth of 2,150 fathoms,-two miles and a half.

Mr. Cheever, in his volume on Hawaii,* has given an interesting chapter on the subject of coral formations. He reasons that as some of the reefs, lagoons, and islands of coral

Life in the Sandwich Islands; or, the Heart of the Pacific,' &c. By the Rev. H. T. Cheever. London, 1851.

GALVANO-ELECTRIC THEORY.

515

rock rise from the sea-bottom at an unfathomable depth, to the conditional height required for the lithophytes to work, the lower portion or foundation must be produced by different and independent causes; and he seeks such agencies in sudden submarine galvanic action, sufficient to separate from the water of the ocean and deposit ridges and piles composed of lime and other substances existing in sea water in enormous quantities, and so universally diffused as to be ever at hand for any purpose. Giving full weight to the amount of material combined with or in solution in the water of the depths of ocean, it is, nevertheless, difficult to conceive a single voltaic action (and it must be single or the effect would not follow) sufficiently strong to raise from the bottom a ridge of separated lime many thousand feet in height, and having a base wide enough to support such a superstructure. As an auxiliary argument Mr. Cheever quotes the opinion of another missionary in the South Seas, Mr. Williams, who puts forward a theory that the calcareous coverings of marine molluscs are not necessarily secreted by the animals themselves, but suggests that they only secrete a sort of gluten, to which calcareous particles in the water adhere, and form a shell. Mr. Williams had probably in his thoughts the common caddis worms found in fresh water. Mr. Cheever goes on to say :-'Let there be a chemical precipitation of the minute calcareous particles floating in sea-water, by any means, and there might be formed a reef-agreeably to the experiment in which the passing of a stream of electric fluid through water having calcareous and siliceous particles in solution produces stone. The lightning in tropical regions, and the electric fluid engendered by submarine and other volcanoes which abound in the South Seas, may thus produce an effect adequate to the formation of those wonderful and invaluable structures. This is a much more rational theory to account for the existence of immense coral reefs and coral islands in the Pacific than that alluded to above, which supposes them wholly the work of saxigenous polypes or lithophytes.'

We need not commit ourselves to the lightning theory, or to

that which supposes the inorganic matter suspended in seawater to become organic by mere adhesion and agglutination to a living animal, to admit readily that the quantity of material suspended in sea-water is sufficient for the production of very extensive formations; and that its elimination is very rapid. Its lime, magnesia, soda, &c., are diffused so generally and so abundantly, that there wants but the creative word and the necessary condition, to cause them to pass into our sight as organic forms. The growth of shelled animals in tropical seas is astonishingly rapid. A friend informs me that, when an officer on board one of the East India Company's ships in 1819, on a voyage from Singapore to China by the eastern passage, the vessel off the south coast of Borneo passed through, during calm weather, continuous tracts of slimy water. Several streaks or planks of the ship about the water-line became covered with small gelatinous substances,-apparently derived from the slimy water. In a short time these substances became small shells, of the Lepas or barnacle kind; and at the end of about four weeks the cephalopods had completely coated that part of the vessel, from stem to stern. They were of all lengths, up to one and a half and two inches; and it was found necessary to take advantage of a calm day to lower all the boats, and to scrape off these rapidly-increasing obstacles to the sailing of the ship. I have myself, quite recently, seen brought on shore on the English coast, two pieces of wood, each about the size of the two open hands, studded as closely with barnacles as the peduncles could be packed, and of greater length than those of the Indian Seas just described.

All this growth proceeded from inorganic material in the water selected and transformed into organic matter by a vital process, as soon as the necessary opportunity for adhesion presented itself. The inference follows, that if the accidental passage of a ship afforded the condition sufficient to reveal or cause organic life to so large an extent, the amount of possible life, even in the one field traversed, that did not receive the proper conditions for its developement, must have been enorWhat, then, must be the entire chemical potentialities

mous.