77. p. 214—“The united Lithophytes.”

According to Linnæus and Ellis the calcareous Zoophytes, (among which Madrepores, Meandrinæ, Astrææ, and Pocilloporæ especially produce mural coral-reefs,) are inhabited and invested by animalcules, which were long supposed to be allied to the Nereids belonging to Cuvier’s Annelida (jointed worms). The anatomy of these gelatinous animalcules has been made known by the acute and comprehensive researches of Cavolini, Savigny, and Ehrenberg. We have learned that, in order to understand the whole organism of the (so-called) rock-building animals, we must not consider the scaffolding which remains after their death, namely, the layers of lime formed into delicate lamellæ by a vital function of secretion, as foreign to the soft membranes of the food-receiving animal.

Besides our increased knowledge of the wonderful formation of the living coral-stocks, a more correct view has gradually gained ground respecting the extensive influence which the coral world has exercised on the appearance of low island groups above the level of the sea, on the migration of land-plants, and the successive extension of the domain of the Floras, and, indeed, in some parts of the ocean, on the distribution of the human race and of languages.

As minute social organisms the corals play an important part in the general economy of nature, although they do not, as people began to believe after Capt. Cook’s voyages of discovery, build up islands or enlarge continents from almost unfathomable depths of the ocean. They excite the liveliest interest, whether regarded as physiological objects, and as illustrating the various gradations of animal form, or in connection with the geography of plants, and the geognostic relations of the earth’s crust. According to the comprehensive views of Leopold von Buch, the whole Jura-formation consists of “large elevated coral-banks of the ancient world, surrounding at a certain distance the old mountain chains.”

According to Ehrenberg’s classification,[KS] coral-animals, (in English works often incorrectly termed coral-insects,) are separable into the monostomous Anthozoa, which are either free and with the power of detaching themselves, as Animal-corals; or are attached in the manner of plants, as Phyto-corals. To the first order (Zoocorallia) belong the Hydras or Armpolyps of Trembley, the Actiniæ, radiant with the most splendid colours, and the mushroom-corals; and to the second order belong the Madrepores, the Astrææ, and the Ocellinæ. The Polyps of the second order are those which from their cellular, wave-resisting, wall-works are the principal subject of this illustration. The wall-work is composed of the aggregate of the coral-trunks, which, however, do not suddenly lose their combined vitality, like a dead forest tree.

Every coral-trunk arises by a process of gemmation in accordance with certain laws, and forms one complete structure, each portion being formed by a great number of organically distinct individual animals. In the group of Phyto-corals these cannot separate themselves spontaneously, but remain united with one another by lamellæ of carbonate of lime. Hence each coral-trunk by no means possesses a central point of common vitality.[KT] The propagation of coral-animals, according to the difference of the orders, is by eggs, spontaneous division or gemmation. This last kind of propagation presents the greatest variety of forms in the development of individuals.

The Coral-reefs (or, as Dioscorides designates them, sea-plants, a forest of stony-trees, Lithodendra), are of three kinds; namely, Coast-reefs, (shore-reefs, fringing-reefs), which are directly connected with continental or insular coasts, as on the north-east coast of New Holland, between Sandy Cape and the dreaded Torres Straits, and almost all the coral-banks of the Red Sea examined for eighteen months by Ehrenberg and Hemprich; Island-surrounding reefs (barrier-reefs, encircling-reefs), as at Vanikoro in the small archipelago of Santa Cruz, north of the New Hebrides, and at Puynipete, one of the Carolinas; and Coral-banks surrounding lagoons (Atolls or Lagoon-islands). This very natural division and nomenclature have been introduced by Charles Darwin, and are most intimately connected with the very ingenious explanation which this intellectual naturalist has given of the gradual origin of these wonderful forms. While, on the one hand, Cavolini, Ehrenberg, and Savigny have completed the scientific anatomical knowledge of the organization of coral-animals, on the other, the geographical and geological relations of coral-islands have been investigated, first by Reinhold and George Forster in Cook’s second voyage, and then, after a long interval, by Chamisso, Péron, Quoy and Gaimard, Flinders, Lütke, Beechey, Darwin, d’Urville, and Lottin.

The coral-animals and their stony cellular scaffoldings belong, for the most part, to the warm tropical seas; and the reefs occur most frequently in the Southern Hemisphere. Thus we find the Atolls or Lagoon Islands crowded together in the so-called coral-sea between the north-east coast of New Holland, New Caledonia, Solomon’s Islands, and the Louisiade Archipelago; in the group of the Low Islands (Low Archipelago), eighty in number; in the Fidji, Ellice, and Gilbert Islands; and in the Indian Ocean, north-east of Madagascar, under the name of the Atoll group of Saya de Malha.

The great Chagos Bank, whose structure and dead coral-trunks have been thoroughly investigated by Captains Moresby and Powell, is the more interesting to us, because we may regard it as a prolongation of the more northern Laccadive and Maldive Islands. I have previously directed attention in another work[KU] to the importance of the order of succession of the Atolls, which are exactly in the direction of a meridian as far as 7° south lat., in reference to the general mountain system, and the form of the earth’s surface, in Central Asia. The meridian-chains, which mark the intersection of many mountain-systems running from east to west at the great bend of the Thibetian river Tzang-bo, correspond with the great meridian mountain rampart of the Ghauts and of the more northern Bolor in further or trans-Gangetic India. Here lie the parallel chains of Cochin China, Siam, and Malacca, as well as those of Ava and Arracan, which, after courses of unequal length, all terminate in the gulfs of Siam, Martaban, and Bengal. The bay of Bengal appears like an arrested effort of nature to produce an inland sea. A deep inbreak of the waters, between the simple western system of the Ghauts, and the very complex eastern trans-Gangetic system, has swallowed up a great part of the eastern lowlands, but met with an impediment not so easily overcome in the early existing and extensive table-land of Mysore.

An oceanic inbreak of this nature has given rise to two almost pyramidal peninsulas of very different length and narrowness; and the prolongation of two opposing meridian systems, the mountain system of Malacca in the east, and the Ghauts of Malabar in the west, manifests itself in submarine, symmetrical series of islands, on the one side in the Andaman and Nicobar Islands, which are poor in corals, and on the other in three long-extended archipelagos of Atolls—the Laccadives, the Maldives, and Chagos. The last, called by mariners the Chagos Bank, forms a lagoon, belted by a narrow, and already much broken coral-reef. The length of this lagoon is 88, and its breadth 72 miles. Whilst the enclosed lagoon is only from 17 to 40 fathoms deep, bottom was scarcely found at a depth of 210 fathoms at a small distance from the outer margin of the coral wall, which appears to be now sinking.[KV] At the coral-lagoon, known as Keeling-Atoll, south of Sumatra, Captain Fitz-Roy states, that at only 2000 yards from the reef, no soundings were found with 7200 feet of line.

“The forms of coral, which in the Red Sea rise in thick wall-like masses, are Mæandrinæ, Astrææ, Favia, Madrepores (Porites), Pocillopora (Hemprichii), Millepores, and Heteropores. The latter are among the most massive, although they are branched. The deepest coral trunks, which magnified by the refraction of light, appear to the eye to resemble the dome of a cathedral, belong, as far as could be determined, to Mæandrinæ and Astrææ.”[KW] A distinction must be made between single and in part free polyp-trunks, and those which form wall-like rocks.

If the accumulation of building polyp-trunks in some regions is so striking, it is no less astonishing to observe the perfect absence of these structures in other and often adjacent regions. Their presence or absence must be determined by certain, still uninvestigated, relations of currents, by the partial temperature of the water, and by the abundance or deficiency of nutriment. That certain delicate-branched corals, with less calcareous deposition on the side opposite to the mouth, prefer the stillness of the interior lagoons, is not to be denied; but this preference for still water must not, as has too often happened,[KX] be regarded as a peculiarity of the whole class of these animals. According to the experiences of Ehrenberg and Chamisso in the Red Sea and in the Marshall Islands, which abound in Atolls and lie east of the Caroline Islands, and according to the observations of Captains Bird Allen and Moresby in the West Indies and in the Maldives, we find that living Madrepores, Millepores, Astræas, and Mæandrinas, can support “a tremendous surf;”[KY] and indeed seem to prefer localities the most exposed to the action of storms. The vital forces of the organism regulating the cellular structure, which with age acquires a rocky hardness, resist most triumphantly the mechanical forces,—the shock of moving waters.

In the South Pacific there is a perfect absence of coral-reefs at the Galapagos and along the whole of the west coast of the New Continent, notwithstanding their vicinity to the numerous Atolls of the Low Islands, and the Archipelago of Mendaña or the Marquesas. It is true that the current of the South Pacific, which washes the coasts of Chili and Peru. (and whose low temperature I observed in the year 1802,) is only 60°.1 Fahr., while the undisturbed water at the sides of the cold current is from 81°.5 to 83°.7 Fahr. at Punta Parima, where it deflects to the west. Moreover at the Galapagos there are small currents between the islands, having a temperature of only 58°.3 Fahr. But this lower temperature does not prevail further northwards along the coasts of the Pacific from Guayaquil to Guatimala and Mexico, neither does it prevail in the Cape de Verd Islands, on the whole west coast of Africa, or at the small islands of St. Paul, St. Helena, Ascension, and San Fernando Noronha; yet in none of these are there coral-reefs.

If this absence of reefs characterises the western coasts of America, Africa, and New Holland, they are, on the other hand, of frequent occurrence on the eastern coasts of tropical America, on the African coast of Zanzibar, and on the southern coast of New South Wales. The best opportunities I have enjoyed for personally examining coral banks have been in the Gulf of Mexico, and south of the Island of Cuba, in the so-called “Gardens of the King and Queen” (Jardines y Jardinillos del Rey y de la Reyna). It was Christopher Columbus himself who, on his second voyage, in May, 1494, gave this name to this little group of islands, because from the pleasant association of the silver-leaved arborescent Tournefortia gnapholoides, of flowering species of Dolichos, of Avicennia nitida, and mangrove-thickets (Rhizophora), the coral-islands formed as it were an archipelago of floating gardens. “Son Cayos verdes y graciosos llenos de arboledas,” says the admiral. On my voyage from Batabano to Trinidad de Cuba, I remained for several days in these gardens, which lie to the east of the great Isle of Pines, abounding in mahogany, for the purpose of determining the longitude of the different Cayos.

The Cayos Flamenco, Bonito, de Diego Perez, and de Piedras, are coral islands, rising only from 8 to 15 inches above the level of the sea. The upper edge of the reef does not consist merely of dead polyp-trunks, but is rather formed of a true conglomerate, in which angular pieces of coral, lying in various directions, are embedded in a cement composed of granules of quartz. In Cayo de Piedras I saw such embedded masses of coral, some of them measuring upwards of three cubic feet. Several of the West Indian smaller coral islands have fresh water, a phenomenon which merits a careful investigation wherever it occurs (as for instance near Radak in the South Sea),[KZ] since it has sometimes been ascribed to hydrostatic pressure, acting from a distant coast (as in Venice, and in the Bay of Xagua, east of Batabano), and sometimes to the filtration of rain-water.[LA]

The living gelatinous covering of the calcareous fabric of the coral-trunks attracts fishes and even turtles in search of food. In the time of Columbus the now desolate district of the Jardines del Rey was animated by a singular branch of industry pursued by the inhabitants of the sea-coasts of Cuba, who availed themselves of a little fish, the Remora, or sucking-fish (the so-called Ship-holder), probably the Echeneis naucrates, for catching turtles. A long and strong line, made of the fibres of the palm, was attached to the tail of the fish. The Remora (called in Spanish Reves, or reversed, because at first sight the back and abdomen might easily be mistaken for each other), attaches itself by suction to the turtle through the indented and moveable cartilaginous plates of the upper shell that covers the head. The Remora, says Columbus, would rather let itself be torn to pieces than relinquish its prey, and the little fish and the turtle are thus drawn out of the water together. “Nostrates,” says Martin Anghiera, the learned secretary of Charles V, “piscem Reversum appellant, quod versus venatur. Non aliter ac nos canibus gallicis per æquora campi lepores insectamur, illi (incolæ Cubæ insulæ) venatorio pisce pisces alios capiebant.”[LB] We learn from Dampier and Commerson, that this artifice of employing a sucking-fish to catch other fishes is very common on the eastern coasts of Africa, near Cape Natal and Mozambique, as well as on the island of Madagascar.[LC] An acquaintance with the habits of animals, and the same necessities, lead to similar artifices and modes of capture amongst tribes having no connection with one another.

Although, as we have already remarked, the actual seat of the Lithophytes who build calcareous walls, lies within a zone extending from 22 to 24 degrees on either side of the equator, yet coral-reefs, favoured, it is supposed, by the warm Gulf Stream, are met with around the Bermudas in 32° 23′ lat., and these have been admirably described by Lieutenant Nelson.[LD] In the southern hemisphere corals (Millepores and Cellepores) are found singly as far as Chiloe and even to the Chonos-Archipelago and Tierra del Fuego, in 53° lat., while Retepores have even been found as far as 72½° lat.

Since Captain Cook’s second voyage, the hypothesis advanced by him as well as by Reinhold and George Forster, that the flat coral islands of the South Pacific have been built up by living agents from the depths of the sea’s bottom, has found numerous advocates. The distinguished naturalists Quoy and Gaimard, who accompanied Captain Freycinet on his voyage of circumnavigation in the frigate “Uranie,” were the first who expressed themselves, in 1823, with much freedom against the views advanced by the two Forsters (father and son), by Flinders, and Péron.[LE] “In directing the attention of naturalists to coral-animalcules,” they say, “we hope to be able to prove that all which has been hitherto affirmed or believed up to the present time, regarding the immense structures they are capable of raising, is for the most part inexact, and in all cases very greatly exaggerated. We are rather of opinion that coral-animalcules, instead of rearing perpendicular walls from the depths of the Ocean, only form strata or incrustrations of some few toises in thickness.” Quoy and Gaimard (p. 289) have also expressed an opinion, that Atolls (coral walls inclosing a lagoon) owe their origin to submarine volcanic craters. They have undoubtedly underrated the depth at which animals who construct coral-reefs (as for example the Astræa) can exist, as they place the extreme limits at from 26 to 32 feet below the level of the sea. Charles Darwin, a naturalist, who has known how to enhance the value of his own observations by a comparison with those of others in many parts of the world, places the region of living coral-animals at a depth of 20 or 30 fathoms,[LF] which corresponds with that in which Professor Edward Forbes found the greatest number of corals in the Ægean Sea. This is Professor Forbes’s fourth region of marine-animals, as given in his ingenious memoir on the Provinces of Depth, and the geographical distribution of Mollusca at perpendicular distances from the surface.[LG] It would appear, however, that the depth at which corals live is very different in the different species, especially in the more delicate ones which do not form such considerable structures.

Sir James Ross, in his Antarctic expedition, brought up corals from a great depth with the lead; and these he remitted for accurate examination to Mr. Stokes and Professor Forbes. Westward of Victoria Land, in the neighbourhood of the Coulman Island, in 72° 31′ south lat., and at a depth of 270 fathoms, Retepora cellulosa, a Hornera, and Prymnoa Rossii. (the latter very similar to a species common to the coasts of Norway,) were found alive and in a perfectly fresh condition.[LH] In the far north too, the Greenland Umbellaria Grœnlandica has been brought up alive by whale fishers from a depth of 236 fathoms.[LI] The same relation between species and locality is met with among sponges, which however are now regarded as belonging more to plants than to zoophytes. On the shores of Asia Minor, the common marine sponge is brought up from depths varying from 5 to 36 fathoms, although one very small species of the same genus is only found at a depth of at least 180 fathoms.[LJ] It is difficult to divine what hinders the Astræas, Madrepores, Mæandrinas, and the whole group of tropical phyto-corals, which are capable of constructing large cellular calcareous walls, from living in very deep strata of water. The decrease of temperature is very gradual, the diminution of light nearly the same, and the existence of numerous Infusoria at great depths of the Ocean proves that there cannot here be any deficiency of food for polyps.

In opposition to the hitherto generally adopted opinion respecting the absence of all organisms and living creatures in the Dead Sea, it is worthy of notice that my friend and fellow-labourer, M. Valenciennes, has received, through the Marquis Charles de l’Escalopier, and through the French Consul Botta, beautiful specimens of Porites elongata from the Dead Sea. This fact is the more interesting, because this species is not found in the Mediterranean, but only in the Red Sea, which, according to Valenciennes, has but few organisms in common with the Mediterranean. As a sea-fish, a species of Pleuronectes, advances far into the interior of France, and accustoms itself to gill-respiration in fresh water, so also does a remarkable flexibility of organization exist in the above-mentioned coral-animal (Porites elongata of Lamarck), as the same species lives both in the Dead Sea, which is supersaturated with salt, and in the open ocean near the Séchelles Islands.[LK]

According to the most recent chemical analyses of the younger Silliman, the genus Porites, like many other cellular coral-trunks (Madrepores, Astræas, and Mæandrinas of Ceylon and the Bermudas), contains besides from 92 to 95 per cent. of carbonate of lime and magnesia, a portion of fluorine and phosphoric acid.[LL] The presence of fluorine in the hard skeleton of the polyps reminds us of the fluoride of calcium found in fish bones according to Morechini’s and Gay-Lussac’s experiments at Rome. Silex is mixed only in very small quantities, with the fluoride of calcium and phosphate of lime found in the coral-trunks; but one coral animal allied to the Horn corals (Gray’s Hyalonema, Glass thread) has an axis of fibres of pure silex, resembling a hanging tuft of hair. Professor Forchhammer, who has recently been engaged in a thorough analysis of sea-water in the most opposite parts of the earth’s surface, finds the quantity of lime in the Caribbean Sea remarkably small, it being only ²⁴⁷⁄₁₀₀₀₀, whilst in the Cattegat it amounts to ³⁷¹⁄₁₀₀₀₀. He is disposed to ascribe this difference to the numerous coral-banks near the West India Islands, which appropriate the lime to themselves, and thus exhaust the sea-water.[LM]

Charles Darwin has with great ingenuity developed the genetic connection between shore-reefs, island-encircling reefs, and lagoon islands, i. e., narrow, annular coral banks which surround inner lagoons. According to his views, these three kinds of structure depend upon the oscillating condition of the bottom of the sea, or on periodical elevations and subsidences. The often-advanced hypothesis, according to which the lagoon-islands, or atolls, mark by their circularly enclosed coral-reefs, the outline of a submarine crater, raised on a volcanic crater-margin, is opposed by the great extent of their diameters, which are in some instances upwards of 30, 40, or even 60 miles. Our fire-emitting mountains have no such craters, and if we would compare the lagoon, with its submerged mural surface and narrow encircling reef, with one of the annular lunar mountains, we must not forget that these annular mountains are not volcanoes, but tracts of land enclosed by walls. According to Darwin, the following is the process of formation. An island mountain closely encircled by a coral reef subsides, while the fringing reef that had sunk with it, is constantly recovering its level owing to the tendency of the coral animals to regain the surface by renewed perpendicular structures; these constitute first a reef encircling the island at a distance, and subsequently, when the inclosed island has wholly subsided, an atoll. According to this view, which regards islands as the most prominent parts, or the culminating points of the submarine land, the relative position of the coral islands would disclose to us what we could scarcely hope to discover by the sounding line, viz., the former configuration and articulation of the land. This attractive subject (to the connection of which with the migrations of plants and the distribution of the races of men we drew attention at the beginning of this note), can only be fully elucidated when we shall succeed in acquiring further knowledge of the depth and nature of the different rocks which serve as a foundation for the lower strata of the dead polyp-trunks.

78. p. 216—“Of the Samothracian Traditions.”

Diodorus has preserved to us these remarkable traditions, the probability of which has invested them with almost historical certainty in the eyes of geologists. The island of Samothrace, once also named Ethiopea, Dardania, and Leucania or Leucosia in the Scholiast of Apollonius Rhodius, the seat of the ancient mysteries of the Cabiri, was inhabited by the remnant of an aboriginal people, several words of whose vernacular language were preserved in later times in sacrificial ceremonies. The position of Samothrace, opposite to the Thracian Hebrus, and near the Dardanelles, explains why a more circumstantial tradition of the great catastrophe of an outburst of the waters of the Pontus (Euxine) should have been especially preserved in this island. Sacred rites were here performed at altars erected on the supposed limits of this inundation; and among the Samothracians, as well as the Bœetians, a belief in the periodical destruction of the human race (a belief which also prevailed among the Mexicans in their myth of the four destructions of the world) was associated with historical recollections of individual inundations.[LN] According to Diodorus, the Samothracians related that the Black Sea had been an inland lake, which, swelled by the influx of rivers (long prior to the inundations which had occurred among other nations) had burst, first through the straits of the Bosphorus, and subsequently through those of the Hellespont.[LO] These ancient revolutions of nature have been considered in a special treatise, by Dureau de la Malle, and all the facts known regarding them collected by Carl von Hoff, in an important work on the subject.[LP] The Samothracian traditions seem reflected as it were in the Sluice-theory of Strato of Lampsacus, according to which the swelling of the waters in the Euxine first formed the passage of the Dardanelles, and next the opening through the Pillars of Hercules. Strabo, in the first book of his Geography, has preserved among the critical extracts from the works of Eratosthenes, a remarkable fragment of the lost work of Strato, which presents views that embrace almost the whole circumference of the Mediterranean.

“Strato of Lampsacus,” says Strabo,[LQ] “enters more fully than the Lydian Xanthus (who has described the impressions of shells far from the sea) into a consideration of the causes of these phenomena. He maintains, that the Euxine had formerly no outlet at Byzantium, but that the pressure of the swollen mass of waters caused by the influx of rivers had opened a passage, whereupon the water rushed into the Propontis and the Hellespont. The same thing also happened to our sea (the Mediterranean), for here too a passage was opened through the isthmus at the Pillars of Hercules, in consequence of the filling of the sea by currents, which in flowing off left the former swampy banks uncovered and dry. In proof of this, Strato affirms, first, that the outer and inner bottoms of the sea are different; then that there is still a bank running under the sea from Europe to Lybia, which shows that the inner and outer sea were formerly not united; next that the Euxine is extremely shallow, while the Cretan, the Sicilian and the Sardinian seas are, on the contrary, very deep; the cause of this being that the former is filled with mud from the numerous large rivers flowing into it from the north. Hence too the Euxine is the freshest, and the streams flowing from it are directed towards the parts where the bottom is deepest. It would also appear that if these rivers continue to flow into the Euxine, it will some day be completely choked with mud, for even now, its left side is becoming marshy in the direction of Salmydessus (the Thracian Apollonia), at the part called by mariners ‘The Breasts,’ before the mouth of the Ister and the desert of Scythia. Perhaps, therefore, the Lybian Temple of Ammon may also have once stood on the sea-shore, its present position in the interior of the country being in consequence of such off-flowings of rivers. Strato also conjectures that the fame and celebrity of the Oracle (of Ammon) is more easily accounted for, on the supposition that the temple was on the sea-shore, since its great distance from the coast would otherwise make its present distinction and fame inexplicable. Egypt also was in ancient times overflowed by the sea as far as the marshes of Pelusium, Mount Casius, and Lake Serbonis; for whenever in digging it happened that salt-water was met with, the borings passed through strata of sea-sand and shells, as if the country had been inundated, and the whole district around Mount Casius and Gerrha had been a marshy sea, continuous with the Gulf of the Red Sea. When the sea (the Mediterranean) retreated, the country was uncovered, leaving, however, the present Lake Serbonis. Subsequently the waters of this lake also flowed off, converting its bed into a swamp. In like manner the banks of Lake Mœris resemble more the shores of a sea than those of a river.” An erroneous reading introduced as an emendation by Grosskurd, in consequence of a passage in Strabo,[LR] gives in place of Mœris, “the Lake Halmyris,” but the latter was situated near the southern mouth of the Danube.

The Sluice-theory of Strato led Eratosthenes of Cyrene (the most celebrated in the series of the librarians of Alexandria) to investigate the problem of the uniformity of level in all external seas flowing round continents, although with less success than Archimedes in his treatise on floating bodies.[LS] The articulation of the northern coasts of the Mediterranean as well as the form of its peninsulas and islands had given origin to the geognostic myth of the ancient land of Lyctonia. The origin of the lesser Syrtis, of the Triton Lake,[LT] and of the whole of Western Atlas,[LU] had been embodied in an imaginary scheme of fire-eruptions and earthquakes.[LV] I have recently entered more fully into this question,[LW] in a passage with which I would be allowed to close this note:

“The northern shore of the Mediterranean possesses the advantage of being more richly and variously articulated than the southern or Lybian shore, and this was, according to Strabo, already noticed by Eratosthenes. Here we find three peninsulas, the Iberian, the Italian, and the Hellenic, which, owing to their various and deeply indented contour, form, together with the neighbouring islands and the opposite coasts, many straits and isthmuses. Such a configuration of continents and of islands that have been partly severed and partly upheaved by volcanic agency in rows, as if over far-extending fissures, early led to geognostic views regarding eruptions, terrestrial revolutions, and outpourings of the swollen higher seas into those below them. The Euxine, the Dardanelles, the Straits of Gades, and the Mediterranean with its numerous islands, were well fitted to originate such a system of sluices. The Orphic Argonaut, who probably lived in the Christian era, has interwoven old mythical narrations in his composition. He sings of the division of the ancient Lyctonia into separate islands, ‘when the dark-haired Poseidon in anger with Father Kronion struck Lyctonia with the golden trident.’ Similar fancies, which may often certainly have sprung from an imperfect knowledge of geographical relations, were frequently elaborated in the erudite Alexandrian school, which was so devoted to everything connected with antiquity. Whether the myth of the breaking up of Atlantis be a vague and western reflection of that of Lyctonia, as I have elsewhere shown to be probable, or whether, according to Otfried Müller, ‘the destruction of Lyctonia (Leuconia) refers to the Samothracian tradition of a great flood, which changed the form of that district,’ is a question which it is here unnecessary to decide.”

79. p. 217—“Precipitation from the clouds.”

The vertical ascent of currents of air is one of the principal causes of the most important meteorological phenomena. Where a desert or a sandy surface devoid of vegetation is surrounded by a high mountain-chain, the sea-wind may be observed driving a dense cloud over the desert, without any precipitation of vapour taking place before it reaches the crest of the mountains. This phenomenon was formerly very unsatisfactorily referred to an attraction supposed to be exercised by the mountain-chain on the clouds. The true cause appears to lie in the ascent from the sandy plain of a column of warm air, which prevents the condensation of the vesicles of vapour. The more barren the surface, and the greater the degree of heat acquired by the sand, the higher will be the ascent of the clouds, and the less readily will the vapour be precipitated. Over the declivities of mountains these causes cease. The play of the vertical column of air is there weaker; the clouds sink, and their disintegration is effected by a cooler stratum of air. Thus deficiency of rain and absence of vegetation in the desert stand in a reciprocal action to one another. It does not rain because the barren and bare surface of sand becomes more strongly heated and radiates more heat; and the desert is not converted into a steppe or grassy plain because without water no organic development is possible.

80. p. 218—“The indurating and heat-emitting mass of the earth.”

If according to the hypothesis of the Neptunists (now long since obsolete), the so-called primitive rocks were also precipitated from a fluid, the transition of the earth’s crust from a condition of fluidity to one of solidity, must have been followed by the liberation of an enormous quantity of caloric, which would have given rise to new evaporation and new precipitations. The more recent these precipitations, the more rapid, the more tumultuous, and the more uncrystalline would they have been. Such a sudden liberation of caloric from the indurating crust of the earth, independent of the latitude, and the position of the earth’s axis, might indeed occasion local elevations of temperature in the atmosphere, which would influence the distribution of plants. The same cause might also occasion a kind of porosity which seems to be indicated by many enigmatical geological phenomena in floetz rocks. I have developed my conjectures on this subject in detail in a small memoir on primitive porosity.[LX] According to the views I have more recently adopted, it appears to me that the variously shattered and fissured earth, with its fused interior, may long have continued in the primeval period, to impart to its oxidised surface a high degree of temperature, independent of its position with respect to the sun and to latitude. What an influence would not, for instance, be exercised for ages to come on the climate of Germany by an open fissure a thousand fathoms in depth, extending from the Adriatic Gulf to the northern coast? Although in the present condition of the earth, long-continued radiation has almost entirely restored the stable equilibrium of temperature first calculated by Fourier in his Théorie analytique de la Chaleur, and the outer atmosphere is now only brought into direct communication with the molten interior of the earth, by means of the insignificant openings of a few volcanoes; yet in the primitive condition of our planet, this interior emitted hot streams of air into the atmosphere through the various clefts and fissures formed by the frequently recurring foldings (or corrugations) of the mountain strata. This emission was wholly independent of latitude. Every newly formed planet must thus in its earliest condition have regulated its own temperature, which was, however, subsequently changed and determined by its position in relation to the central body, the sun. The moon’s surface also exhibits traces of this reaction of the interior upon the crust.

81. p. 218—“The mountain-declivities of the most southern parts of Mexico.”

The spherical greenstone in the mountain district of Guanaxuato is perfectly similar to that of the Fichtelberg in Franconia. Both form grotesque domes, which break through and are superimposed on transition argillaceous schists. In the same manner pearl-stone, porphyritic schist, trachyte, and pitch-stone porphyry present analogous forms in the Mexican mountains, near Cinapecuaro and Moran, in Hungary, Bohemia, and in Northern Asia.

82. p. 220—“The Colossal Dragon-tree of Orotava.”

This colossal dragon-tree (Dracæna draco) stands in the garden of M. Franqui, in the little town of Orotava, called formerly Taoro, one of the most charming spots in the world. In June, 1799, when we ascended the Peak of Teneriffe, we found that this enormous tree measured 48 feet in circumference. Our measurement was made at several feet above the root. Nearer to the ground Le Dru found it nearly 79 feet. Sir G. Staunton asserts that at an elevation of ten feet from the ground, its diameter is still 12 feet. The height of the tree is not much more than 69 feet. According to tradition it would appear that this tree was venerated by the Guanches (as was the ash-tree of Ephesus by the Greeks, the Plantain of Lydia, which Xerxes decorated with ornaments, also the sacred Banyan-tree of Ceylon), and that in the year 1402, which was the period of Béthencourt’s first expedition, it was as large and as hollow as in the present day. When it is remembered that the dragon-tree is everywhere of very slow growth, we may conclude that the one at Orotava is of extreme antiquity. Berthollet says, in his description of Teneriffe, “On comparing the young dragon-trees which grows near this colossal tree, the calculations we are led to make on the age of the latter strike the mind with astonishment.”[LY] The Dragon-tree has been cultivated from the most ancient times in the Canary isles, in Madeira, and Porto Santo, and that accurate observer, Leopold von Buch, found it growing wild near Iguesti in Teneriffe. Its original habitat is not therefore the East Indies, as has long been believed; and its appearance does not afford any refutation of the opinion of those who regard the Guanches as a wholly isolated primitive Atlantic race, having no intercourse with African or Asiatic nations: The form of the Dracænæ is repeated on the southern extremity of Africa, in the Isle of Bourbon, in China, and in New Zealand. In these remotely distant regions we recognise species of the same genus, but none are to be found in the New Continent, where this form is supplied by the Yucca. The Dracæna borealis of Aiton is a true Convallaria, the nature of both being perfectly identical.[LZ]

I have given a representation, in the last plate of the Picturesque Atlas of my American journey,[MA] of the dragon-tree of Orotava, taken from a drawing made in 1776 by F. d’Ozonne, and which I found among the posthumous papers of the celebrated Borda, in the still unprinted journal entrusted to me by the Dépôt de la Marine, and from which I have borrowed important astronomically-determined geographical, data besides many barometrical and trigonometrical notices.[MB] The measurement of the dragon-tree in the Villa Franqui was made in Borda’s first voyage with Pingré in 1771, and not in the second, made 1776 with Varela. It is asserted, that in the fifteenth century, during the early periods of the Norman and Spanish conquests, mass was performed at a small altar erected in the hollow trunk of this tree. Unfortunately, the Dracæna of Orotava lost one side of its leafy top in the storm of the 21st of July, 1819. There is a fine large English copper-plate engraving, which gives an exceedingly true representation of the present condition of the tree.

The monumental character of these colossal living forms, and the impression of reverence which they have created among all nations, have led, in modern times, to a more careful study of the numerical determination of their age, and of the size of their trunks. The results of such investigations induced the elder Decandolle, (the author of the important treatise, entitled De la Longévité des Arbres,) Endlicher, Unger, and other distinguished botanists to conjecture, that the age of many existing vegetable forms may extend to the earliest historical times, if not to the records of the Nile, at least to those of Greece and Italy. In the Bibliothèque Universelle de Genève (t. xlvii. 1831, p. 50) we find the following passage: “Numerous examples seem to confirm the idea, that there still exist, on our planet, trees of a prodigious antiquity—the witnesses, perhaps, of one or more of its latest physical revolutions. If we consider a tree as the combination of as many individual forms as there have been buds developed on its surface, one cannot be surprised if the aggregate resulting from the continual addition of new buds to the older ones, should not necessarily have any fixed termination to its existence.” In the same manner, Agardh says: “If in each solar year new parts be formed in the plant, and the older hardened ones be replaced by new parts capable of conducting sap, we have a type of growth limited by external causes alone.” He ascribes the short duration of the life of herbaceous plants, “to the preponderance of the production of blossoms and fruit over the formation of leaves.” Unfruitfulness in a plant insures a prolongation of its life. Endlicher adduces the instance of an individual plant of Medicago sativa, var. β versicolor, which lived eighty years because it bore no fruit.[MC]

To the dragon-trees, which, notwithstanding the gigantic development of their closed vascular bundles, must be classed, in respect to their floral parts, in the same natural family as Asparagus and the garden onion, belongs the Adansonia, (the monkey bread-tree, Baobab), undoubtedly among the largest and most ancient inhabitants of our planet. In the earliest voyages of discovery made by Catalans and Portuguese, the sailors were accustomed to carve their names on these two species of trees; not always from a mere wish of perpetuating their memory, but also as “marcos,” or signs of possession, and of the rights which nations assume in virtue of first discovery. The Portuguese mariners often selected for carving on the trees, as a “marco,” or mark of possession, the elegant French motto talent de bien faire, so frequently employed by the Infante Don Henrique, the Discoverer. Thus Manuel de Faria y Sousa says expressly;[MD] “Era uso de los primeros Navegantes de dexar inscrito el motto del Infante, talent de bien faire, en la corteza de los arboles.”[ME] (It was the custom of the early navigators to inscribe the motto of the Infante in the bark of the trees.)

The above-named motto, cut on the bark of two trees by Portuguese navigators in the year 1435, and therefore twenty-eight years before the death of the Infante Don Henrique, Duke of Viseo, is singularly connected, in the history of discoveries, with the discussions that have arisen from a comparison of Vespucci’s fourth voyage with that of Gonzalo Coelho (1503). Vespucci relates, that the Admiral’s ship of Coelho’s squadron was wrecked on an island which was sometimes supposed to be that of San Fernando Noronha; sometimes, Peñedo de San Pedro; and sometimes, the problematical island of St. Matthew. The last-named island was discovered on the 15th of October, 1525, by Garcia Jofre de Loaysa in 2½ south lat., in the meridian of Cape Palmas, and almost in the Gulf of Guinea. He remained there eighteen days at anchor, and found crosses, orange-trees that had become wild, and two trunks of trees having inscriptions that bore the date of ninety years back.[MF] I have in another place,[MG] in an inquiry regarding the trustworthiness of Amerigo Vespucci, more fully considered this problem.

The oldest description of the Baobab (Adansonia digitata) is that of the Venetian, Aloysius Cadamosto. (whose real name was Alvise da Ca da Mosto) in 1454. He found at the mouth of the Senegal. (where he joined Antoniotto Usodimare), trunks, whose circumference he estimated at 17 fathoms, or 112 feet.[MH] He might have compared them to dragon-trees, which he had already seen. Perrottet says,[MI] that he had seen monkey-bread fruit trees, which had a diameter of about thirty-two feet, with a height of only from seventy to eighty-five feet. The same dimensions had been given by Adanson in his voyage, 1748. The largest trunks of the monkey bread-fruit trees, which he himself saw, in 1749, some on one of the small Magdalena islands near Cape de Verd, and others at the mouth of the Senegal, were from 26 to nearly 29 feet in diameter, with a height of little more than 70 feet, and a top measuring upwards of 180 feet across. Adanson, however, makes the remark that other travellers had found trunks having a diameter of about 32 feet.[MJ] French and Dutch sailors had carved their names on the trunks in characters six inches in length. One of these inscriptions was of the fifteenth century,[MK] while all the others were of the sixteenth. From the depth of the cuts, which are covered with new layers of wood,[ML] and from a comparison of the thickness of trunks, whose various ages were known, Adanson computed the age of trees having a diameter of 32 feet at 5150 years.[MM] He however cautiously subjoins the following remarks, in a quaint mode of spelling which I do not alter: “le calcul de l’aje de chake couche n’a pas d’exactitude géometrike.” In the village of Grand Galarques, also in Senegambia, the negroes have adorned the entrance of a hollow Baobab with carvings cut out of wood still green. The inner cavity serves as a place of general meeting in which the community debate on their interests. This hall reminds us of the hollow (specus) in the interior of a plantain in Lycia, in which the Roman ex-consul, Lucinius Mutianus, entertained twenty-one guests. Pliny (xii. 3) gives to a cavity of this kind the somewhat ample breadth of eighty Roman feet. The Baobab was seen by René Caillié in the valley of the Niger near Jenne, by Cailliaud in Nubia, and by Wilhelm Peters along the whole eastern coast of Africa, where this tree, which is called Mulapa, i.e. Nlapa-tree, or more correctly muti-nlapa, advances as far as Lourenzo Marques, almost to 26° south lat. The oldest and thickest trunks seen by Peters “measured from 60 to 75 feet in circumference.” Although Cadamosto observed, in the fifteenth century, eminentia non quadrat magnitudini; and although Golberry[MN] found, in the “Vallée des deux Gagnacks,” trunks only 64 feet in height whose diameter was 36 feet, this disproportion between thickness and height must not be assumed to be general. “Very old trees,” says the learned traveller, Peters, “lose their crowns by gradual decay, while they continue to increase in circumference. On the eastern coast of Africa one not unfrequently meets with trees having a diameter of more than 10 feet which reach the height of nearly 70 feet.”

While therefore the bold calculations of Adanson and Perrottet assign to the Adansonias measured by them, an age of 5150 or even 6000 years, which would make them coeval with the builders of the Pyramids, or even with Menes, and would place them in an epoch when the Southern Cross was still visible in Northern Germany;[MO] the more certain estimations yielded by annular rings, and by the relation found to exist between the thickness of the layer of wood and the duration of growth, give us, on the other hand, shorter periods for our temperate northern zone. Decandolle finds that of all European species of trees, the yew attains the greatest age; and according to his calculations, 30 centuries must be assigned as the age of the Taxus baccata of Braburn in Kent, from 25 to 26 to the Scotch yew of Fortingal, and 14½ and 12 respectively to those of Crowhurst in Surrey and Ripon (Fountains Abbey) in Yorkshire.[MP] Endlicher remarks that “another yew-tree in the churchyard of Grasford, North Wales, which measures more than 50 feet in girth below the branches, is more than 1400 years old, whilst one in Derbyshire is estimated at 2096 years. In Lithuania linden trees have been felled which measured 87 feet round, and in which 815 annular rings have been counted.”[MQ] In the temperate zone of the southern hemisphere some species of the Eucalyptus attain an enormous girth, and as they at the same time attain a height of nearly 250 feet, they afford a singular contrast to our yew trees, which are colossal only in thickness. Mr. Backhouse found in Emu Bay, on the shore of Van Diemen’s Land, Eucalyptus trunks which, with a circumference of 70 feet at the base, measured as much as 50 feet at a little more than 5 feet from the ground.[MR]

It was not Malpighi, as has been generally asserted, but the intellectual Michel Montaigne, who had the merit of first showing, in 1581, in his Voyage en Italie, the relation that exists between the annual rings and the age of the tree.[MS] An intelligent artisan, engaged in the preparation of astronomical instruments, first drew Montaigne’s attention to the significance of the annual rings, asserting that the part of the trunk directed towards the north had narrower rings. Jean Jacques Rousseau entertained the same opinion; and his Emile, when he loses himself in the forest, is made to direct his course in accordance with the deposition of the layers of wood. Recent phyto-anatomical observations[MT] teach us, however, that the acceleration of vegetation as well as the remission of growth, and the varying production of the circles of the ligneous bundles (annual deposits) from the cambium cells, depend on other influences than position with respect to the quarter of the heavens.

Trees which in the case of some examples attain a diameter of more than 20 feet, and an age of many centuries, belong to very different natural families. We may here instance Baobabs, Dragon trees, various species of Eucalyptus, Taxodium distichum. (Rich.,) Pinus Lambertiana. (Douglasii,) Hymenæa Courbaril, Cæsalpinieæ, Bombax, Swietenia Mahagoni, the Banyan tree (Ficus religiosa), Liriodendron tulipifera(?), Platanus orientalis, and our Lindens, Oaks, and Yews. The celebrated Taxodium distichon, the Ahuahuete of the Mexicans (Cupressus disticha, Linn., Schubertia disticha, Mirbel), of Santa Maria del Tule, in the State of Oaxaca, has not a diameter of 60 feet, as stated by Decandolle, but exactly 40½ feet.[MU] The two beautiful Ahuahuetes which I have frequently seen at Chapoltepec (growing in what was probably once a garden or pleasure ground of Montezuma) measure, according to the instructive account in Burkardt’s travels (bd. i. s. 268) only 36 and 38 feet in circumference, and not in diameter, as has often been erroneously maintained. The Buddhists of Ceylon venerate the colossal trunk of the sacred fig-tree of Anurahdepura. The Banyan, which takes root by its branches, often attains a thickness of 30 feet, and forms, as Onesicritus truly expresses himself, a leafy roof resembling a many-pillared tent.[MV] On the Bombax Ceiba see early notices from the time of Columbus in Bembo.[MW]

Among those oak trees which have been very accurately measured, the largest in Europe is undoubtedly the one near Saintes on the road to Cozes, in the Department de la Charente inférieure. This tree, which has an elevation of 64 feet, measures very nearly 30 feet in diameter near the ground, while 5 feet higher up it is nearly 23 feet, and where the main branches begin more than 6 feet. A little room, from 10 feet 8 inches to 12 feet 9 inches in width and 9 feet 7 inches in height, has been cleared in the dead part of the trunk, and a semi-circular bench cut within it from the green wood. A window gives light to the interior, and hence the walls of this little room, which is closed by a door, are gracefully clothed with ferns and lichens. From the size of a small piece of wood that had been cut out over the door, and in which two hundred ligneous rings were counted, the age of the oak of Saintes must be estimated at 1800 or 2000 years.[MX]

With respect to the rose-tree (Rosa canina) reputed to be a thousand years old, which grows in the crypt of the Cathedral of Hildesheim, I learn from accurate information, based on authentic records, for which I am indebted to the kindness of the Stadtgerichts-Assessor Römer, that the main stem only has an age of eight hundred years. A legend connects this rose-tree with a vow of the first founder of the cathedral, Louis the Pious; and a document of the eleventh century says, “that when Bishop Hezilo rebuilt the cathedral, which had been burnt down, he enclosed the roots of the rose-tree within a vault still remaining, raised on the latter the walls of the crypt, which was re-consecrated in 1061, and spread the branches of the rose-tree over its sides.” The stem, still living, is nearly 27 feet in height, and only 2 inches thick, and spreads across a width of 82 feet over the outer wall of the eastern crypt. It is undoubtedly of very considerable antiquity, and well worthy of the renown it has so long enjoyed throughout Germany.

If excessive size, in point of organic development, may in general be regarded as a proof of a long protraction of life, special attention is due, among the thalassophytes of the submarine vegetable world, to a species of fucus, Macrocystis pyrifera, Agardh (Fucus giganteus). This marine plant attains, according to Captain Cook and George Forster, a length of 360 feet, and exceeds therefore the height of the loftiest Coniferous trees, not excepting Sequoia gigantea, Endl. (Taxodium sempervirens, Hook, and Arnott) of California.[MY] Captain Fitz-Roy has confirmed this statement.[MZ] Macrocystis pyrifera grows from 64° south lat. to 45° north lat., as far as the Bay of San Francisco on the north-west coast of the New Continent; indeed Joseph Hooker believes that this species of Fucus advances as far as Kamtschatka. In the waters of the Antarctic seas it is even seen floating between the pack-ice.[NA] The cellular band and thread-like structures of the Macrocystis (which are attached to the bottom of the sea by an adhesive organ resembling a claw) seem to be limited in their length by accidental disturbing causes alone.