Chapter III: Part 3

While this absence of coral reefs appears to characterise the _western_ coasts of Africa, America, and Australia, on the other hand such reefs abound on the _eastern_ coasts of tropical America, of Africa, on the coasts of Zanzibar and Australia, and on that of New South Wales. The coral banks which I have chiefly had opportunities of observing are those of the interior of the Gulf of Mexico, and those to the south of the Island of Cuba, in what are called the “Gardens of the King and Queen” (Jardines y Jardinillos del Rey y de la Reyna). It was Columbus himself who, on his second voyage, in May 1494, gave that name to this little group of islands, because the agreeable mixture of the silver-leaved arborescent Tournefortia gnapholoides, flowering species of Dolichos, Avicennia nitida, and mangrove hedges, gave to the coral islands the appearance of a group of floating gardens. “Son Cayos verdes y graciosos llenos de arboledas,” says the Admiral. On the passage from Batabano to Trinidad de Cuba, I remained several days in these gardens, situated to the east of the larger island, called the Isla de Pinos, which is rich in mahogany trees: my stay was for the purpose of determining the longitude of the different keys (Cayos). The Cayo Flamenco, Cayo Bonito, Cayo de Diego Perez, and Cayo de piedras, are coral islands rising only from eight to fourteen inches above the level of the sea. The upper edge of the reef does not consist simply of blocks of dead coral; it is rather a true conglomerate, in which angular pieces of coral, cemented together with grains of quartz, are embedded. In the Cayo de piedras I saw such embedded pieces of coral measuring as much as three cubic feet. Several of the small West Indian coral islands have fresh water, a phenomenon which, wherever it presents itself, (for example, at Radak in the Pacific; see Chamisso in Kotzebue’s Entdeckungs-Reise, Bd. iii. S. 108), is deserving of examination, as it has sometimes been ascribed to hydrostatic pressure operating from a distant coast, (as at Venice, and in the Bay of Xagua east of Batabano), and sometimes to the filtration of rain water. (See my Essai politique sur l’Ile de Cuba, T. ii. p. 137.)

The living gelatinous investment of the stony calcareous part of the coral attracts fish, and even turtles, who seek it as food. In the time of Columbus the now unfrequented locality of the Jardines del Rey was enlivened by a singular kind of fishery, in which the inhabitants of the coasts of the Island of Cuba engaged, and in which they availed themselves of the services of a small fish. They employed in the capture of turtle the Remora, once said to detain ships (probably the Echeneis Naucrates), called in Spanish “Reves,” or reversed, because at first sight his back and abdomen are mistaken for each other. The remora attaches itself to the turtle by suction through the interstices of the indented and moveable cartilaginous plates which cover the head of the latter, and “would rather,” says Columbus, “allow itself to be cut in pieces than lose its hold.” The natives; therefore, attach a line, formed of palm fibres, to the tail of the little fish, and after it has fastened itself to the turtle draw both out of the water together. Martin Anghiera, the learned secretary of Charles V., says, “Nostrates 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.” (Petr. Martyr, Oceanica, 1532, Dec. I. p. 9; Gomara, Hist. de las Indias, 1553, fol. xiv.) We learn by Dampier and Commerson that this piscatorial artifice, the employing a sucking-fish to catch other inhabitants of the water, is much practised on the East Coast of Africa, at Cape Natal and on the Mozambique Channel, and also in the Island of Madagascar. (Lacépède, Hist. nat. des Poissons, T. i. p. 55.) The same necessities combine with a knowledge of the habits of animals to induce the same artifices and modes of capture among nations who are entirely unconnected with each other.

Although, as we have already remarked, the zone included between 22 or 24 degrees of latitude on either side of the equator, appears to be the true region of the calcareous saxigenous lithophytes which raise wall-like structures, yet coral reefs are also found, favoured it is supposed by the warm current of the Gulf-stream, in lat. 32° 23´, at the Bermudas, where they have been extremely well described by Lieutenant Nelson. (Transactions of the Geological Society, 2d Series, 1837, Vol. V. Pt. i. p. 103.) In the southern hemisphere, corals, (Millepores and Cellepores), are found singly as far south as Chiloe, the Archipelago of Chonos, and Tierra de Fuego, in 53° lat.; and Retepores are even found in lat. 72-1/2°.

Since the second voyage of Captain Cook there have been many defenders of the hypothesis put forward by him as well as by Reinhold and George Forster, according to which the low coral islands of the Pacific have been built up by living creatures from the depths of the bottom of the sea. The distinguished investigators of nature, Quoy and Gaimard, who accompanied Captain Freycinet in his voyage round the world in the frigate Uranie, were the first who ventured, in 1823, to express themselves with great boldness and freedom in opposition to the views of the two Forsters (father and son), of Flinders, and of Péron. (Annales des Sciences Naturelles, T. vi., 1825, p. 273.) “En appelant l’attention des naturalistes sur les animalcules des coraux, nous espérons démontrer que tout ce qu’on a dit ou cru observer jusqu’à ce jour relativement aux immenses travaux qu’il sont susceptibles d’exécuter, est le plus souvent inexact et toujours excessivement exagéré. Nous pensons que les coraux, loin d’élever des profondeurs de l’océan des murs perpendiculaires, ne forment que des couches ou des encroûtemens de quelques toises d’èpaisseur.” Quoy and Gaimard also propounded (p. 289) the conjecture that the Atolls, (coral walls enclosing a lagoon), probably owed their origin to submarine volcanic craters. Their estimate of the depth below the surface of the sea at which the animals which form the coral reefs (the species of Astræa, for example) could live, was doubtless too small, being at the utmost from 25 to 30 feet (26-1/2 to 32 E.) An investigator and lover of nature who has added to his own many and valuable observations a comparison with those of others in all parts of the globe, Charles Darwin, places with greater certainty the depth of the region of living corals at 20 to 30 fathoms. (Darwin, Journal, 1845, p. 467; and the same writer’s Structure of Coral Reefs, p. 84-87; and Sir Robert Schomburgk, Hist. of Barbadoes, 1848, p. 636.) This is also the depth at which Professor Edward Forbes found the greatest number of corals in the Egean Sea: it is his “fourth region” of marine animals in his very ingenious memoir on the “Provinces of Depth” and the geographical distribution of Mollusca at vertical distances from the surface. (Report on Ægean Invertebrata in the Report of the 13th Meeting of the British Association, held at Cork in 1843, pp. 151 and 161.) The depths at which corals live would seem, however, to be very different in different species, and especially in the more delicate ones which do not form such large masses.

Sir James Ross, in his Antarctic Expedition, brought up corals with the sounding lead from great depths, and entrusted them to Mr. Stokes and Professor Forbes for more thorough examination. On the west of Victoria Land, near Coulman Island, in S. lat. 72° 31´, at a depth of 270 fathoms, Retepora cellulosa, a species of Hornera, and Prymnoa Rossii, were found quite fresh and living. Prymnoa Rossii is very analogous to a species found on the coast of Norway. (See Ross, Voyage of Discovery in the Southern and Antarctic Regions, vol. i. pp. 334 and 337.) In a similar manner in the high northern regions the whalers have brought up Umbellaria grænlandica, living, from depths of 236 fathoms. (Ehrenberg, in the Abhandl. der Berl. Akad. aus dem J. 1832, S. 430.) We find similar relations of species and situation among sponges, which, indeed, are now considered to belong rather to plants than to zoophytes. On the coasts of Asia Minor the common sponge is found by those engaged in the fishery at depths varying from 5 to 30 fathoms; whereas a very small species of the same genus is not found at a less depth than 180 fathoms. (Forbes and Spratt, Travels in Lycia, 1847, Vol. ii. p. 124.) It is difficult to divine the reason which prevents Madrepores, Meandrina, Astræa, and the entire group of tropical Phyto-corals which raise large cellular calcareous structures, from living in strata of water at a considerable depth below the surface of the sea. The diminution of temperature in descending takes place but slowly; that of light almost equally so; and the existence of numerous Infusoria at great depths shews that the polypifers would not want for food.

In opposition to the hitherto generally received opinion of the entire absence of organic life in the Dead Sea, it is deserving of notice that my friend and fellow labourer, M. Valenciennes, has received through the Marquis Charles de l’Escalopier, and also the French consul Botta, fine specimens of Porites elongata from the Dead Sea. This fact is the more interesting because this species is not found in the Mediterranean, but belongs to the Red Sea, which, according to Valenciennes, has but few organic forms in common with the Mediterranean. I have before remarked that in France a sea fish, a species of Pleuronectes, advances far up the rivers into the interior of the country, thus becoming accustomed to gill-respiration in fresh water; so we find that the coral-animal above spoken of, the Porites elongata of Lamarck, has a not less remarkable flexibility of organisation, since it lives in the Dead Sea, which is over-saturated with salt, and in the open ocean near the Seychelle Islands. (See my Asie Centrale, T. ii. p. 517.)

According to the most recent chemical analyses made by the younger Silliman, the genus Porites, as well as many other cellular polypifers, (Madrepores, Andræas, and Meandrinas of Ceylon and the Bermudas), contain, besides 92-95 per cent. of carbonate of lime and magnesia, some fluoric and phosphoric acids. (See p. 124-131 of “Structure and Classification of Zoophytes,” by James Dana, Geologist of the United States’ Exploring Expedition, under the command of Captain Wilkes.) The presence of fluorine in the solid parts of polypifers reminds us of the fluorate of lime in the bones of fishes, according to the experiments of Morechini and Gay Lussac at Rome. Silex is only found mixed in very small quantity with fluorate and phosphate of lime in coral stocks; but a coral-animal allied to the Horn-coral, Gray’s Hyalonema, has an axis of pure fibres of silex resembling a queue or braided tress of hair. Professor Forchhammer, who has been lately engaged in a thorough analysis of the sea-water from the most different parts of the globe, finds the quantity of lime in the Caribbean Sea remarkably small, being only 247 parts in ten thousand, while in the Categat it amounts to 371 parts in ten thousand. He is disposed to attribute this difference to the many coral-banks among the West Indian Islands, which appropriate the lime, and lower the per centage remaining in the sea-water. (Report of the 16th Meeting of the British Association for the Advancement of Science, held in 1846, p. 91.)

Charles Darwin has developed in a very ingenious manner the probable genetic connection between fringing or shore-reefs, island-encircling reefs, and lagoon-islands, _i. e._, narrow ring-shaped reefs enclosing interior lagoons. According to his views these three varieties of form are dependent on the oscillating condition of the bottom of the sea, or on periodic elevations and subsidences. The hypothesis which has been several times put forward, according to which the closed ring or annular form of the coral-reefs in Atolls or Lagoon Islands marks the configuration of a submarine volcano, the structure having been raised on the margin of the crater, is opposed by their great dimensions, the diameters of many of them being 30, 40, and sometimes even 60 geographical miles. Our fire-emitting mountains have no such craters; and if we would compare the lagoon, with its submerged interior and narrow enclosing reef, to one of the annular mountains of the moon, we must not forget that those lunar mountains are not volcanoes, but wall-surrounded districts. According to Darwin, the process of formation is the following:--He supposes a mountainous island surrounded by a coral-reef, (a “fringing reef” attached to the shore), to undergo subsidence: the “fringing reef” which subsides with the island is continually restored to its level by the tendency of the coral-animals to regain the surface of the sea, and becomes thus, as the island gradually sinks and is reduced in size, first an “encircling reef” at some distance from the included islet, and subsequently, when the latter has entirely disappeared, an atoll. According to this view, in which islands are regarded as the culminating points of a submerged land, the relative positions of the different coral islands would disclose to us that which we could hardly learn by the sounding line, concerning the configuration of the land which was above the surface of the sea at an earlier epoch. The entire elucidation of this attractive subject, (to the connection of which with the migrations of plants and the diffusion of races of men attention was called at the commencement of the present note), can only be hoped for when inquirers shall have succeeded in obtaining greater knowledge than is now possessed of the depth and the nature of the rocks on which the lowest strata of the dead corals rest.

[8] p. 11.--“_Traditions of Samothrace._”

Diodorus has preserved to us this remarkable tradition, the probability of which renders it in the eyes of the geologist almost equivalent to a historical certainty. The Island of Samothrace, formerly called also Æthiopea, Dardania, Leucania or Leucosia in the Scholiast to Apollonius Rhodius, and which was a seat of the ancient mysteries of the Cabiri, was inhabited by the remains of an ancient nation, several words of whose language were preserved to a later period in the ceremonies accompanying sacrifices. The situation of this island, opposite to the Thracian Hebrus and near the Dardanelles, renders it not surprising that a more detailed tradition of the catastrophe of the breaking forth of the waters of the Euxine should have been preserved there. Rites were performed at altars supposed to mark the limits of the irruption of the waves; and in Samothrace as well as in Bœotia, a belief in the periodically recurring destruction of mankind, (a belief which was also found among the Mexicans in the form of a myth of four destructions of the world), was connected with historical recollections of particular inundations. (Otfr. Müller Geschichten Hellenischer Stämme und Städte, Bd. i. S. 65 and 119.) According to Diodorus, the Samothracians related that the Black Sea had once been an inland lake, but that, being swollen by the rivers which flow into it, it had broken through, first the strait of the Bosphorus, and afterwards that of the Hellespont; and this long before the inundations spoken of by other nations. (Diod. Sicul. lib. v. cap. 47, p. 369, Wesseling.) These ancient revolutions of nature have been treated of in a special work by Dureau de la Malle, and all the information possessed on the subject has been collected in Carl von Hoff’s important work, entitled Geschichte der natürlichen Veränderungen der Erdoberfläche, Th. i. 1822, S. 105-162; and in Creuzer’s Symbolik, 2te Aufl. Th. ii. S. 285, 318, and 361. A reflex, as it were, of the traditions of Samothrace appears in the “Sluice theory” of Strato of Lampsacus, according to which the swelling of the waters of the Euxine first opened the passage of the Dardanelles, and afterwards caused the outlet through the pillars of Hercules. Strabo has preserved to us in the first book of his Geography, among critical extracts from the works of Eratosthenes, a remarkable fragment of the lost writings of Strato, presenting views which extend to almost the entire circumference of the Mediterranean.

“Strato of Lampsacus,” says Strabo (Lib. i. p. 49 and 50, Casaub.), “is even more disposed than the Lydian Xanthus,” (who had described impressions of shells at a distance from the sea) “to expound the causes of the things which we see. He asserts that the Euxine had formerly no outlet at Byzantium, but the sea becoming swollen by the rivers which ran into it, had by its pressure opened the passage through which the waters flow into the Propontis and the Hellespont. He also says that the same thing has happened to our Sea (the Mediterranean);” “for here, too, when the sea had become swollen by the rivers, (which in flowing into it had left dry their marshy banks), it forced for itself a passage through the isthmus of land connecting the Pillars. The proofs which Strato gives of this are, first that there is still a bank under water running from Europe to Libya, shewing that the outer and inner seas were formerly divided; and next that the Euxine is the shallowest, the Cretan, Sicilian, and Sardoic Seas being on the contrary very deep; the reason being that the Euxine has been filled with mud by the many and large rivers flowing into it from the North, while the other seas continued deep. The Euxine is also the freshest, and the waters flow towards the parts where the bottom of the sea is lowest. Hence he inferred that the whole of the Euxine would finally be choked with mud if the rivers were to continue to flow into it: and this is already in some degree the case on the west side of the Euxine towards Salmydessus (the Thracian Apollonia), and at what are called by mariners the “Breasts” off the mouth of the Ister and along the shore of the Scythian Desert. Perhaps the Temple of Ammon (in Lybia) may once have stood on the sea-shore, and causes such as these may explain why it is now far inland. This Strato thought might account for the celebrity of the Oracle, which would be less surprising if it had been on the sea-shore; whereas its great distance from the coast made its present renown inexplicable. Egypt, too, had been formerly overflowed by the sea as far as the marshes of Pelusium, Mount Casius, and Lake Serbonis; for, on digging beneath the surface, beds of sea-sand and shells are found; shewing that the country was formerly overflowed, and the whole district round Mount Casius and Gerrha was a marshy sea which joined the gulf of the Red Sea. When our Sea (the Mediterranean) retreated, the land was uncovered; still, however, leaving the Lake of Serbonis: subsequently this lake also broke through its bounds and the water flowed off, so that the lake became a swamp. The banks of Lake Mœris are also more like sea than river banks.” An erroneously corrected reading introduced by Grosskurd on account of a passage in Strabo, Lib. xvii. p. 809, Cas., gives instead of Mœris “the Lake Halmyris:” but this latter lake was situated not far from the mouth of the Danube.

The sluice-theory of Strato led Eratosthenes of Cyrene (the most celebrated of the series of librarians of Alexandria, but less happy than Archimedes in writing on floating bodies), to examine the problem of the equality of level of all external seas, _i. e._, seas surrounding the Continents. (Strabo, Lib. i. p. 51-56; Lib. ii. p. 104, Casaub). The varied outlines of the northern shores of the Mediterranean, and the articulated form of the peninsulas and islands, had given occasion to the geognostical myth of the ancient land of Lyctonia. The supposed mode of origin of the smaller Syrtis and of the Triton Lake (Diod. iii. 53-55) as well as that of the whole Western Atlas (Maximus Tyrius, viii. 7) were drawn in to form part of an imaginary scheme of igneous eruptions and earthquakes. (See my Examen crit. de l’hist. de la Géographie, Vol. i. p. 179; T. iii. p. 136.) I have recently touched more in detail on this subject (Kosmos, Bd. ii. S. 153; Engl. ed. p. 118-119) in a passage which I permit myself to subjoin:--

A more richly varied and broken outline gives to the northern shore of the Mediterranean an advantage over the southern or Lybian shore, which according to Strabo was remarked by Eratosthenes. The three great peninsulas, the Iberian, the Italian, and the Hellenic, with their sinuous and deeply indented shores, form, in combination with the neighbouring islands and opposite coasts, many straits and isthmuses. The configuration of the continent and the islands, the latter either severed from the main or volcanically elevated in lines, as if over long fissures, early led to geognostical views respecting eruptions, terrestrial revolutions, and overpourings of the swollen higher seas into those which were lower. The Euxine, the Dardanelles, the Straits of Gades, and the Mediterranean with its many islands, were well fitted to give rise to the view of such a system of sluices. The Orphic Argonaut, who probably wrote in Christian times, wove antique legends into his song; he describes the breaking up of the ancient Lyktonia into several islands, when ‘the dark-haired Poseidon, being wroth with Father Kronion, smote Lyktonia with the golden trident.’ Similar phantasies, which indeed may often have arisen from imperfect knowledge of geographical circumstances, proceeded from the Alexandrian school, where erudition abounded, and a strong predilection was felt for antique legends. It is not necessary to determine here whether the myth of the Atlantis broken into fragments should be regarded as a distant and western reflex of that of Lyktonia (as I think I have elsewhere shewn to be probable), or whether, as Otfried Müller considers, “the destruction of Lyktonia (Leuconia) refers to the Samothracian tradition of a great flood which had changed the form of that district.”

[9] p. 12.--“_Prevents precipitation taking place from clouds._”

The vertically-ascending current of the atmosphere is a principal cause of many most important meteorological phenomena. When a desert or a sandy plain partly or entirely destitute of plants is bounded by a chain of high mountains, we see the sea breeze drive the dense clouds over the desert without any precipitation taking place before they have reached the mountain-ridge. This phenomenon was formerly explained in a very inappropriate manner by a supposed superior attraction exercised by the mountains on the clouds. The true reason of the phenomenon appears to consist in the ascending column of warm air which rises from the sandy plain, and prevents the vesicles of vapour from being dissolved. The more complete the absence of vegetation, and the more the sand is heated, the greater is the height of the clouds, and the less can any fall of rain take place. When the clouds reach the mountains these causes cease to operate; the play of the vertically-ascending atmospheric current is feebler, the clouds sink lower, and dissolve in rain in a cooler stratum of air. Thus, in deserts, the _want of rain_, and the _absence of vegetation_, act and react upon each other. It does not rain, because the naked sandy surface having no vegetable covering, becomes more powerfully heated by the solar rays, and thus radiates more heat; and the absence of rain forbids the desert being converted into a steppe or grassy plain, because without water no organic development is possible.

[10] p. 14.--“_The mass of the earth in solidifying and parting with its heat._”

If, according to the hypothesis of the Neptunists, now long since obsolete, the so-called primitive rocks were precipitated from a fluid, the transition of the crust of the earth from a fluid to a solid state must have been accompanied by an enormous disengagement of heat, which would in turn have caused fresh evaporation and fresh precipitations. The later these precipitations, the more rapid, tumultuous, and uncrystalline they would have been. Such a sudden disengagement of heat _might_ cause local augmentations of temperature independent of the height of the pole or the latitude of the place, and independent of the position of the earth’s axis; and the temperatures thus caused would influence the distribution of plants. The same sudden disengagement of heat might also occasion a species of porosity, of which there seem to be indications in many enigmatical geological phenomena in sedimentary rocks. I have developed these conjectures in detail in a small memoir “über ursprungliche Porosität.” (See my work entitled Versuche über die chemische Zersetzung des Luftkreises, 1799, S. 177; and Moll’s Jahrbücher der Berg- und Hüttenkunde, 1797, S. 234.) According to the newer views which I now entertain, the shattered and fissured earth, with her molten interior, may long have maintained a high temperature on her oxydised surface, independently of position in respect to the sun and of latitude. Would not the climate of Germany be wonderfully altered, and that perhaps for centuries, if there were opened a fissure a thousand fathoms in depth, reaching from the shores of the Adriatic to the Baltic? If in the present condition of our planet, the stable equilibrium of temperature, first calculated by Fourier in his Théorie analytique de la chaleur, has been almost completely restored by radiation from the earth into space; and if the external atmosphere now only communicates with the molten interior through the inconsiderable openings of a few volcanoes,--in the earlier state of things numerous clefts and fissures, produced by the frequently recurring corrugations of the rocky strata of the globe, emitted streams of heated air which mingled with the atmosphere and were entirely independent of latitude. Every planet must thus in its earliest condition have for a time determined its own temperature, which afterwards becomes dependent on the position relatively to the central body, the Sun. The surface of the Moon also shows traces of this reaction of the interior upon the crust.

[11] p. 14.--“_The mountain declivities of the southern part of Mexico._”

The greenstone in globular concretions of the mountain district of Guanaxuato is quite similar to that of the Franconian Fichtel-Gebirge. Both form grotesquely shaped summits, which pierce through and cover the transition argillaceous schists. In the same manner, pearl stone, porphyritic schists, trachyte, and pitch-stone porphyry, constitute rocks similar in form in the Mexican mountains near Cinapecuaro and Moran, in Hungary, in Bohemia, and in Northern Asia.

[12] p. 16.--“_The dragon-tree of Orotava._”

This colossal dragon-tree, Dracæna draco, stands in the garden of Dr. Franqui in the small town of Oratava, the ancient Taoro, one of the most delightful spots in the world. In June 1799, when we ascended the Peak of Teneriffe, we measured the circumference of the tree, and found it nearly 48 English feet. Our measurement was taken several feet above the root. Lower down, and nearer to the ground, Le Dru made it nearly 79 English feet. Sir George Staunton found the diameter still as much as 12 feet at the height of 10 feet above the ground. The height of the tree is not much above 69 English feet. According to tradition, this tree was venerated by the Guanches (as was the ash-tree of Ephesus by the Greeks, or as the Lydian plane-tree which Xerxes decked with ornaments, and the sacred Banyan-tree of Ceylon), and at the time of the first expedition of the Béthencourts in 1402, it was already as thick and as hollow as it now is. Remembering that the Dracæna grows extremely slowly, we are led to infer the high antiquity of the tree of Orotava. Bertholet, in his description of Teneriffe, says, “En comparant les jeunes Dragonniers, voisins de l’arbre gigantesque, les calculs qu’on fait sur l’age de ce dernier effraient l’imagination.” (Nova Acta Acad. Leop. Carol. Naturæ Curiosorum, T. xiii. 1827, p. 781.) The dragon-tree has been cultivated in the Canaries, and in Madeira and Porto Santo, from the earliest times; and an accurate observer, Leopold von Buch, has even found it wild in Teneriffe, near Igueste. Its original country, therefore, is not India, as had long been believed; nor does its appearance in the Canaries contradict the opinion of those who regard the Guanches as having been an isolated Atlantic nation without intercourse with African or Asiatic nations. The form of the Dracænas is repeated at the southern extremity of Africa, in the Isle of Bourbon, and in New Zealand. In all these distant regions species of the genus in question are found, but none have been met with in the New Continent, where its form is replaced by that of the Yucca. Dracæna borealis of Aiton is a true Convallaria, and has all the “habitus” of that genus. (Humboldt, Rel. hist. T. i. p. 118 and 639.) I have given a representation of the dragon-tree of Orotava, taken from a drawing made by F. d’Ozonne in 1776, in the last plate of the Picturesque Atlas of my American journey. (Vues des Cordillères et Monumens des Peuples indigènes de l’Amérique, Pl. lxix.) I found d’Ozonne’s drawing among the manuscripts left by the celebrated Borda, in the still unprinted travelling journal entrusted to me by the Dépôt de la Marine, and from which I borrowed important astronomically-determined geographical, as well as barometric and trigonometric notices. (Rel. hist. T. i. p. 282.) The measurement of the dragon-tree of the Villa Franqui was made on Borda’s first voyage with Pingré, in 1771; not in his second voyage, in 1776, with Varela. It is affirmed that in the early times of the Norman and Spanish Conquests, in the 15th century, Mass was said at a small altar erected in the hollow trunk of the tree. Unfortunately the dragon-tree of Orotava lost one side of its top in the storm of the 21st of July, 1819. There is a fine and large English copperplate engraving which represents the present state of the tree with remarkable truth to nature.

The monumental character of these colossal living vegetable forms, and the kind of reverence which has been felt for them among all nations, have occasioned in modern times the bestowal of greater care in the numerical determination of their age and the size of their trunks. The results of these inquiries have led the author of the important treatise, “De la longévité des Arbres,” the elder Decandolle, Endlicher, Unger, and other able botanists, to consider it not improbable that the age of several individual trees which are still alive goes back to the earliest historical periods, if not of Egypt, at least of Greece and Italy. It is said in the Bibliothèque Universelle de Genève, 1831, T. lxvii. p. 50:--“Plusieurs exemples semblent confirmer l’idée qu’il existe encore sur le globe des arbres d’une antiquité prodigieuse, et peut-être témoins de ses dernières révolutions physiques. Lorsqu’on regarde un arbre comme un agrégat d’autant d’individus soudés ensemble qu’il s’est développé de bourgeons à sa surface, on ne peut pas s’étonner si, de nouveaux bourgeons s’ajoutant sans cesse aux anciens, l’agrégat qui en résulte n’a point de terme nécessaire à son existence.” In the same manner Agardh says:--“If in trees there are produced in each solar year new parts, so that the older hardened parts are replaced by new ones capable of conducting sap, we see herein a type of growth limited only by external causes.” He ascribes the shortness of the life of herbs, or of such plants as are not trees, “to the preponderance of the production of flowers and fruit over the formation of leaves.” Unfruitfulness is to a plant a prolongation of life. Endlicher cites the example of a plant of Medicago sativa, var. β versicolor, which, bearing no fruit, lived eighty years. (Grundzüge der Botanik, 1843, S. 1003).

With the dragon trees, which, notwithstanding the gigantic development of their closed vascular bundles, must by reason of their floral parts be placed in the same natural family with asparagus and garden onions, we must associate the Adansonia (monkey bread-tree, Baobab,) as being certainly among the largest and oldest inhabitants of our planet. In the very first voyages of discovery of the Catalans and Portuguese, the navigators were accustomed to cut their names on these two species of trees, not merely to gratify the desire of handing down their names, but also to serve as marks or signs of possession, and of whatever rights nations claim on the ground of being the first discoverers. The Portuguese navigators often used as their “marco” or token of possession the French motto of the Infant Don Henrique the Discoverer. Manuel de Faria y Sousa says in his Asia Portuguesa (T. i. cap. 2, pp. 14 and 18):--“Era uso de los primeros Navegantes de dexar inscrito el Motto del Infante, _talent de bien faire_, en la corteza de los arboles.” (Compare also Barros, Asia, Dec. I. liv. ii. cap. 2, T. i. p. 148; Lisboa, 1778.)

The above-named motto cut on the bark of two trees by Portuguese navigators in 1435, twenty-eight years therefore before the death of the Infante, is curiously connected in the history of discoveries with the elucidations to which the comparison of Vespucci’s fourth voyage with that of Gonzalo Coelho, in 1503, has given rise. Vespucci relates that Coelho’s admiral’s ship was wrecked on an island which has been sometimes supposed to be San Fernando Noronha, sometimes the Peñedo de San Pedro, and sometimes the problematical Island of St. Matthew. This last-named island was discovered by Garcia Jofre de Loaysa on the 15th of October, 1525, in 2-1/2° S. lat., in the meridian of Cape Palmas, almost in the Gulf of Guinea. He remained there eighteen days at anchor, found crosses, as well as orange trees which had been planted and had become wild, and on two trunks of trees inscriptions dating back ninety years. (Navarrete, T. v. pp. 8, 247, and 401.) I have examined the questions presented by this account more in detail in my inquiries into the trustworthiness of Amerigo Vespucci. (Examen critique de l’hist. de la Geographie, T. v. pp. 129-132.)

The oldest description of the Baobab (Adansonia digitata), is that given by the Venetian Aloysius Cadamosto (the real name was Alvise da Ca da Mosto), in 1454. He found at the mouth of the Senegal, trunks of which he estimated the circumference at seventeen fathoms, or 102 feet, (Ramusio, Vol. i. p. 109): he might have compared them with Dragon trees which he had seen before. Perrottet says in his “Flore de Sénégambie” (p. 76), that he had seen monkey bread-trees which, with a height of only about 70 or 80 feet, had a diameter of 32 English feet. The same dimensions had been given by Adanson, in the account of his voyage in 1748; the largest trunks which he himself saw (in 1749) in one of the small Magdalena islands near Cape de Verd, and in the vicinity of the mouth of the Senegal River, were from 26 to 28-1/2 English feet in diameter, with a height of little more than 70 feet, and a top about 180 feet broad; but he adds at the same time, that other travellers had found trunks of nearly 32 English feet diameter. French and Dutch sailors had cut their names on the trees seen by Adanson in letters half a foot long; the dates added to the names shewed these inscriptions to be all of the 16th century, except one which belonged to the 15th. (In Adanson’s “Familles des Plantes,” 1763, P. I. pp. ccxv.-ccxviii., it stands as the 14th century, but this is doubtless an error of inadvertence.) From the depth of the inscriptions, which were covered with new layers of wood, and from the comparison of the thickness of different trunks of the same species in which the relative age of the trees was known, Adanson computed the probable age of the larger trees, and found for a diameter of 32 English feet 5150 years. (Voyage au Sènegal, 1757, p. 66.) He prudently adds (I do not alter his curious orthography):--“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 ornamented the entrance of a hollow Baobab tree with sculptures cut out of the still fresh wood; the interior serves for holding meetings in which their interests are debated. Such a hall of assembly reminds one of the hollow or cave (specus) of the plane tree in Lycia, in which Lucinius Mutianus, who had previously been consul, feasted with twenty-one guests. Plino (xii. 8) assigns to such a cavity in a hollow tree the somewhat large allowance of a breadth of eighty Roman feet. The Baobab was seen by Réné Caillié in the Valley of the Niger near Jenne, by Caillaud in Nubia, and by Wilhelm Peters along the whole eastern coast of Africa (where it is called Mulapa, _i. e._ Nlapa-tree, more properly Muti-nlapa) as far as Lourenzo Marques, almost to 26° of S. lat. Although Cadamosto said in the 15th century “eminentia non quadrat magnitudini,” and although Golberry (Fragmens d’un Voyage en Afrique, T. ii. p. 92) found in the “Vallée des deux Gagnacks” trunks which, with 36 English feet diameter near the roots, were only 64 English feet high, yet this great disproportion between height and thickness must not be regarded as general. The learned traveller Peters remarks that “very old trees lose height by the gradual decay of the top, while they continue to increase in girth. On the East Coast of Africa one sees not unfrequently trunks of little more than ten feet diameter reach a height of 69 English feet.”

If, according to what has been said, the bold estimations of Adanson and Perottet assign to the Adansonias measured by them an age of from 5150 to 6000 years, which would make them contemporaneous with the epoch of the building of the Pyramids or even with that of Menes, a period when the constellation of the Southern Cross was still visible in Northern Germany (Kosmos, Bd. iii. S. 402 and 487; Eng. ed. p. 293, and note 146), on the other hand, the more secure estimations made from the annual rings of trees in our northern temperate zone, and from the ratio which has been found to subsist between the thickness of the layer of wood and the time of growth, give us shorter periods. Decandolle finds as the result of his inquiries, that of all European species of trees the yew is that which attains the greatest age. He assigns to the yew (Taxus baccata) of Braborne, in the county of Kent, thirty centuries; to the Scotch yew of Fortingal, from twenty-five to twenty-six; and to those of Crowhurst in Surrey, and Ripon in Yorkshire, respectively, fourteen and a half and twelve centuries. (Decandolle, de la longévité des arbres, p. 65.) Endlicher remarks that the age of another yew tree, in the Churchyard of Grasford, in North Wales, which measures 52 English feet in circumference below the branches, is estimated at 1400 years, and that of a yew in Derbyshire at 2096 years. In Lithuania lime trees have been cut down which were 87 English feet in circumference, and in which 815 annual rings have been counted. (Endlicher, Grundzüge der Botanik, S. 399.) In the temperate zone of the southern hemisphere some species of Eucalyptus attain an enormous girth, and as they also reach to a great stature (above 230 Paris, 245 English, feet), they are singularly contrasted with our yew trees, whose great dimension is in thickness only. Mr. Backhouse found in Emu Bay, on the coast of Van Diemen Land, trunks of Eucalyptus which measured 70 English feet round the trunk near the ground, and five feet higher up 50 English feet. (Gould, Birds of Australia, Vol. I. Introd. p. xv.)

It is not, as is commonly stated, Malpighi, but the ingenious Michel Montaigne, who has the merit of having been the first, in 1581, in his Voyage en Italie, to notice the relation of the annual rings to the age of the tree. (Adrien de Jussieu, Cours élémentaire de Botanique, 1840, p. 61.) A skilful artist, engaged in the preparation of astronomical instruments, had called the attention of Montaigne to the annual rings; and he also maintained that the rings were narrower on the north side of the tree. Jean Jacques Rousseau had the same belief; and his Emile, if he loses himself in a forest, is to direct himself by the indications afforded by the relative thickness of the layers of wood. More recent observations on the anatomy of plants teach us, however, that both the acceleration and also the retardation or intermission of growth, or the varying production of circles of ligneous fascicles (annual deposits) from the Cambium cells, depend on influences which are wholly distinct from the quarter of the heavens towards which one side of the annual rings is turned. (Kunth, Lehrbuch der Botanik, 1847, T. i. S. 146 and 164; Lindley, Introduction to Botany, 2d edition, p. 75.)

Trees which in individual cases attain a diameter of more than twenty feet, and an age extending to many centuries, belong to the most different natural families. I may name here Baobabs, Dragon-trees, some species of Eucalyptus, Taxodium disticum (Rich.), Pinus Lambertiana (Douglas), Hymenæa courbaril, Cæsalpinieæ, Bombax, Swietenia mahagoni, the Banyan tree (Ficus religiosa), Liriodendron tulipifera? Platanus orientalis, and our Limes, Oaks, and Yews. The celebrated Taxodium distichon, the Ahuahuete of the Mexicans, (Cupressus disticha Linn., Schubertia disticha Mirbel); at Santa Maria del Tule, in the state of Oaxaca, has not a diameter of 57, as Decandolle says, but of exactly 38 French (40-1/2 English) feet. (Mühlenpfordt, Versuch einer getreuen Schilderung der Republik Mexico, Bd. i. S. 153.) The two fine Ahuahuetes near Chapoltepec, which I have often seen, and which are probably the surviving remnants of an ancient garden or pleasure-ground of Montezuma, measure, (according to Burkart’s account of his travels, Bd. i. S. 268, a work which otherwise contains much information), only 36 and 38 English feet in circumference; not in diameter, as has often been erroneously asserted. The Buddhists in Ceylon venerate the gigantic trunk of the sacred fig-tree of Anourahdepoura. The Indian fig-tree or Banyan, of which the branches take root round the parent stem, forming, as Onesicritus well described, a leafy canopy resembling a many-pillared tent, often attain a thickness of 28 (29-1/2 English) feet diameter. (Lassen, Indische Alterthumskunde, Bd. i. S. 260.) On the Bombax ceiba, see early notices of the time of Columbus, in Bembo’s Historiæ Venetæ, 1551, fol. 83.

Among oak-trees, of those which have been accurately measured, the largest in Europe is no doubt that near the town of Saintes, in the Departement de la Charente Inférieure, on the road to Cozes. This tree, which is 60 (64 English) feet high, has a diameter of 27 feet 8-1/2 inches (29-1/2 English feet) near the ground; 21-1/2 (almost 23 English) feet five feet higher up; and where the great boughs commence 6 Parisian feet (6 feet 5 inches English.) In the dead part of the trunk a little chamber has been arranged, from 10 feet 8 inches to 12 feet 9 inches wide, and 9 feet 8 inches high (all English measure), with a semi-circular bench cut out of the fresh wood. A window gives light to the interior, so that the sides of the chamber (which is closed with a door) are clothed with ferns and lichens, giving it a pleasing appearance. Judging by the size of a small piece of wood which has been cut out above the door, and in which the marks of 200 annular rings have been counted, the oak of Saintes would be between 1800 and 2000 years old. (Annales de la Société d’Agriculture de la Rochelle, 1843, p. 380.)

In the wild rose-tree of the crypt of the Cathedral of Hildesheim, said to be a thousand years old, it is the root only, and not the stem, which is eight centuries old, according to accurate information derived from ancient and trustworthy original documents, for the knowledge of which I am indebted to the kindness of Stadtgerichts-Assessor Römer. A legend connects the rose-tree with a vow made by the first founder of the cathedral, Ludwig the Pious; and an original document of the 11th century says, “that when Bishop Hezilo rebuilt the cathedral which had been burnt down, he enclosed the roots of the rose-tree with a vault which still exists, raised upon this vault the crypt, which was re-consecrated in 1061, and spread out the branches of the rose-tree upon the walls.” The stem now living is 26-1/2 feet high and about two inches thick, and the outspread branches cover about 32 feet of the external wall of the eastern crypt; it is doubtless of considerable antiquity, and well deserving of the celebrity which it has gained throughout Germany.

If extraordinary development in point of size is to be regarded as a proof of long continued organic life, particular attention is due to one of the thalassophytes of the sub-marine vegetable world, _i. e._, to the Fucus giganteus, or Macrocystis pyrifera of Agardh. According to Captain Cook and George Forster, this sea-plant attains a length of 360 English feet; surpassing, therefore, the height of the loftiest Coniferæ, even that of the Sequoia gigantea, Endl., or Taxodium sempervirens, Hook and Arnott, which grows in California. (Darwin, Journal of Researches into Natural History, 1845, p. 239; and Captain Fitz-Roy in the Narrative of the Voyages of the Adventure and Beagle, vol. ii. p. 363.) Macrocystis pyrifera is found from 64° south to 45° north latitude, as far as San Francisco on the north-west coast of America; and Joseph Hooker believes it to extend as far as Kamtschatka. In the Antarctic seas it is even seen floating among the pack-ice. (Joseph Hooker, Botany of the Antarctic Voyage under the command of Sir James Ross, 1844, pp. 7, 1, and 178; Camille Montagne, Botanique cryptogame du Voyage de la Bonite, 1846, p. 36.) The immense length to which the bands or ribbands and the cords or lines of the cellular tissue of the Macrocystis attain, appears to be limited only by accidental injuries.

[13] p. 17.--“_Species of phænogamous plants already contained in herbariums._”

We must carefully distinguish between three different questions: How many species of plants are described in printed works? how many have been discovered, _i. e._ are contained in herbariums, though without being described? how many are probably existing on the globe? Murray’s edition of the Linnean system contains, including cryptogamia, only 10042 species. Willdenow, in his edition of the Species Plantarum, between the years 1797 and 1807, had already described 17457 phænogamous species, (from Monandria to Polygamia diœcia.) If we add 3000 cryptogamous species, we obtain the number which Willdenow mentions, viz. 20000 species. More recent researches have shown how much this estimation of the number of species described and contained in herbariums falls short of the truth. Robert Brown counted above 37000 phænogamous plants. (General Remarks on the Botany of Terra Australis, p. 4.) I afterwards attempted to give the geographical distribution (in different parts of the earth already explored), of 44000 phænogamous and cryptogamous plants. (Humboldt, de distributione geographica Plantarum, p. 23.) Decandolle found, in comparing Persoon’s Enchiridium with his Universal System in 12 several families, that the writings of botanists and European herbariums taken together might be assumed to contain upwards of 56000 species of plants. (Essai élementaire de Géographie botanique, p. 62.) If we consider how many species have since that period been described by travellers,--(my expedition alone furnished 3600 of the 5800 collected species of the equinoctial zone),--and if we remember that in all the botanical gardens taken together there are certainly above 25000 phænogamous plants cultivated, we shall easily perceive how much Decandolle’s number falls short of the truth. Completely unacquainted as we still are with the larger portions of the interior of South America,--(Mato-Grosso, Paraguay, the eastern declivity of the Andes, Santa Cruz de la Sierra, and all the countries between the Orinoco, the Rio Negro, the Amazons, and Puruz),--of Africa, Madagascar, Borneo, and Central and Eastern Asia,--the thought rises involuntarily in the mind that we may not yet know the third, or probably even the fifth part of the plants existing on the earth! Drège has collected 7092 species of phænogamous plants in South Africa alone. (See Meyer’s pflanzen geographische Documente, S. 5 and 12.) He believes that the Flora of that district consists of more than 11000 phænogamous species, while on a surface of equal area (12000 German, or 192000 English square geographical miles) von Koch has described in Germany or Switzerland 3300, and Decandolle in France 3645 species of phænogamous plants. I would also recall that even now new Genera, (some even consisting of tall forest trees), are being discovered in the small West Indian Islands which have been visited by Europeans for three centuries, and in the vicinity of large commercial towns. These considerations, which I propose to develop in further detail at the close of the present annotation, make it probable that the actual number of species exceeds that spoken of in the old myth of the Zend-Avesta, which says that “the Primeval Creating Power called forth from the blood of the sacred bull 120000 different forms of plants!”

If, then, we cannot look for any direct scientific solution of the question of how many forms of the vegetable kingdom,--including leafless Cryptogamia (water Algæ, funguses, and lichens), Characeæ, liver-worts, mosses, Marsilaceæ, Lycopodiaceæ, and ferns,--exist on the dry land and in the ocean in the present state of the organic life of our globe, we may yet attempt an approximate method by which we may find some probable “lowest limits” or numerical minima. Since 1815, I have sought, in arithmetical considerations relating to the geography of plants, to examine first the ratios which the number of species in the different natural families bear to the entire mass of the phænogamous vegetation in countries where the latter is sufficiently well known. Robert Brown, the greatest botanist among our cotemporaries, had previously determined the numerical proportions of the leading divisions of the vegetable kingdom; of Acotyledons (Agamæ, Cryptogamic or cellular plants) to Cotyledons (Phanerogamic or vascular plants), and of Monocotyledonous (Endogenous) to Dicotyledonous (Exogenous) plants. He finds the ratio of Monocotyledons to Dicotyledons in the tropical zone as 1 : 5, and in the cold zones of the parallels of 60° N. and 55° S. latitude, as 1 : 2-1/2. (Robert Brown, General Remarks on the Botany of Terra Australis, in Flinders’ Voyage, vol. ii. p. 338.) The absolute number of species in the three leading divisions of the vegetable kingdom are compared together in that work according to the method there laid down. I was the first to pass from these leading divisions to the divisions of the several families, and to consider the ratio which the number of species of each family bears to the entire mass of phænogamous plants belonging to a zone of the earth’s surface. (Compare my memoir entitled De distributione geographica Plantarum secundum cœli temperiem et altitudinem montium, 1817, p. 24-44; and the farther development of the subject of these numerical relations given by me in the Dictionnaire des Sciences naturelles, T. xviii. 1820, p. 422-436; and in the Annales de Chimie et de Physique, T. xvi. 1821, p. 267-292.)

The numerical relations of the forms of plants, and the laws observed in their geographical distribution, may be considered in two very different ways. If plants are studied in their arrangement according to natural families, without regard to their geographical distribution, it is asked, What are the fundamental forms or types of organisation to which the greatest number of species correspond? Are there on the entire surface of the earth more Glumaceæ than Compositæ? Do these two orders make up between them one-fourth part of the whole number of phænogamous plants? What is the proportion of Monocotyledons to Dicotyledons? These are questions of General Phytology, or of the science which investigates the organisation of plants and their mutual connection, or the present state of the entire vegetable world.