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Porto Praya -- Ribeira Grande -- Atmospheric Dust with Infusoria -- Habits of a Sea-slug and Cuttle-fish -- St. Paul's Rocks, non-volcanic -- Singular Incrustations -- Insects the first Colonists of Islands -- Fernando Noronha -- Bahia -- Burnished Rocks -- Habits of a Diodon -- Pelagic Confervae and Infusoria -- Causes of discoloured Sea.

Rio de Janeiro -- Excursion north of Cape Frio -- Great Evaporation -- Slavery -- Botofogo Bay -- Terrestrial Planariae -- Clouds on the Corcovado -- Heavy Rain -- Musical Frogs -- Phosphorescent insects -- Elater, springing powers of -- Blue Haze -- Noise made by a Butterfly -- Entomology -- Ants -- Wasp killing a Spider -- Parasitical Spider -- Artifices of an Epeira -- Gregarious Spider -- Spider with an unsymmetrical web.

Monte Video -- Maldonado -- Excursion to R. Polanco -- Lazo and Bolas -- Partridges -- Absence of trees -- Deer -- Capybara, or River Hog -- Tucutuco -- Molothrus, cuckoo-like habits -- Tyrant-flycatcher -- Mocking-bird -- Carrion Hawks -- Tubes formed by lightning -- House struck.

Rio Negro -- Estancias attacked by the Indians -- Salt-Lakes -- Flamingoes -- R. Negro to R. Colorado -- Sacred Tree -- Patagonian Hare -- Indian Families -- General Rosas -- Proceed to Bahia Blanca -- Sand Dunes -- Negro Lieutenant -- Bahia Blanca -- Saline incrustations -- Punta Alta -- Zorillo.

Bahia Blanca -- Geology -- Numerous gigantic extinct Quadrupeds -- Recent Extinction -- Longevity of Species -- Large Animals do not require a luxuriant vegetation -- Southern Africa -- Siberian Fossils -- Two Species of Ostrich -- Habits of Oven-bird -- Armadilloes -- Venomous Snake, Toad, Lizard -- Hybernation of Animals -- Habits of Sea-Pen -- Indian Wars and Massacres -- Arrowhead -- Antiquarian Relic.

Set out for Buenos Ayres -- Rio Sauce -- Sierra Ventana -- Third Posta -- Driving Horses -- Bolas -- Partridges and Foxes -- Features of the country -- Long-legged Plover -- Teru-tero -- Hail-storm -- Natural enclosures in the Sierra Tapalguen -- Flesh of Puma -- Meat Diet -- Guardia del Monte -- Effects of cattle on the Vegetation -- Cardoon -- Buenos Ayres -- Corral where cattle are slaughtered.

Excursion to St. F? -- Thistle Beds -- Habits of the Bizcacha -- Little Owl -- Saline streams -- Level plains -- Mastodon -- St. F? -- Change in landscape -- Geology -- Tooth of extinct Horse -- Relation of the Fossil and recent Quadrupeds of North and South America -- Effects of a great drought -- Parana -- Habits of the Jaguar -- Scissor-beak -- Kingfisher, Parrot, and Scissor-tail -- Revolution -- Buenos Ayres -- State of Government.

Excursion to Colonia del Sacramiento -- Value of an Estancia -- Cattle, how counted -- Singular breed of Oxen -- Perforated pebbles -- Shepherd-dogs -- Horses broken-in, Gauchos riding -- Character of Inhabitants -- Rio Plata -- Flocks of Butterflies -- A?ronaut Spiders -- Phosphorescence of the Sea -- Port Desire -- Guanaco -- Port St. Julian -- Geology of Patagonia -- Fossil gigantic Animal -- Types of Organisation constant -- Change in the Zoology of America -- Causes of Extinction.

Santa Cruz -- Expedition up the River -- Indians -- Immense streams of basaltic lava -- Fragments not transported by the river -- Excavation of the valley -- Condor, habits of -- Cordillera -- Erratic boulders of great size -- Indian relics -- Return to the ship -- Falkland Islands -- Wild horses, cattle, rabbits -- Wolf-like fox -- Fire made of bones -- Manner of hunting wild cattle -- Geology -- Streams of stones -- Scenes of violence -- Penguin -- Geese -- Eggs of Doris -- Compound animals.

Tierra del Fuego, first arrival -- Good Success Bay -- An account of the Fuegians on board -- Interview with the savages -- Scenery of the forests -- Cape Horn -- Wigwam Cove -- Miserable condition of the savages -- Famines -- Cannibals -- Matricide -- Religious feelings -- Great Gale -- Beagle Channel -- Ponsonby Sound -- Build wigwams and settle the Fuegians -- Bifurcation of the Beagle Channel -- Glaciers -- Return to the Ship -- Second visit in the Ship to the Settlement -- Equality of condition amongst the natives.

Strait of Magellan -- Port Famine -- Ascent of Mount Tarn -- Forests -- Edible fungus -- Zoology -- Great Seaweed -- Leave Tierra del Fuego -- Climate -- Fruit-trees and productions of the southern coasts -- Height of snow-line on the Cordillera -- Descent of glaciers to the sea -- Icebergs formed -- Transportal of boulders -- Climate and productions of the Antarctic Islands -- Preservation of frozen carcasses -- Recapitulation.

Valparaiso -- Excursion to the foot of the Andes -- Structure of the land -- Ascend the Bell of Quillota -- Shattered masses of greenstone -- Immense valleys -- Mines -- State of miners -- Santiago -- Hot-baths of Cauquenes -- Gold-mines -- Grinding-mills -- Perforated stones -- Habits of the Puma -- El Turco and Tapacolo -- Humming-birds.

Chiloe -- General aspect -- Boat excursion -- Native Indians -- Castro -- Tame fox -- Ascend San Pedro -- Chonos Archipelago -- Peninsula of Tres Montes -- Granitic range -- Boat-wrecked sailors -- Low's Harbour -- Wild potato -- Formation of peat -- Myopotamus, otter and mice -- Cheucau and Barking-bird -- Opetiorhynchus -- Singular character of ornithology -- Petrels.

San Carlos, Chiloe -- Osorno in eruption, contemporaneously with Aconcagua and Coseguina -- Ride to Cucao -- Impenetrable forests -- Valdivia -- Indians -- Earthquake -- Concepcion -- Great earthquake -- Rocks fissured -- Appearance of the former towns -- The sea black and boiling -- Direction of the vibrations -- Stones twisted round -- Great Wave -- Permanent Elevation of the land -- Area of volcanic phenomena -- The connection between the elevatory and eruptive forces -- Cause of earthquakes -- Slow elevation of mountain-chains.

Valparaiso -- Portillo Pass -- Sagacity of mules -- Mountain-torrents -- Mines, how discovered -- Proofs of the gradual elevation of the Cordillera -- Effect of snow on rocks -- Geological structure of the two main ranges, their distinct origin and upheaval -- Great subsidence -- Red snow -- Winds -- Pinnacles of snow -- Dry and clear atmosphere -- Electricity -- Pampas -- Zoology of the opposite sides of the Andes -- Locusts -- Great Bugs -- Mendoza -- Uspallata Pass -- Silicified trees buried as they grew -- Incas Bridge -- Badness of the passes exaggerated -- Cumbre -- Casuchas -- Valparaiso.

Coast-road to Coquimbo -- Great loads carried by the miners -- Coquimbo -- Earthquake -- Step-formed terraces -- Absence of recent deposits -- Contemporaneousness of the Tertiary formations -- Excursion up the valley -- Road to Guasco -- Deserts -- Valley of Copiap? -- Rain and Earthquakes -- Hydrophobia -- The Despoblado -- Indian ruins -- Probable change of climate -- River-bed arched by an earthquake -- Cold gales of wind -- Noises from a hill -- Iquique -- Salt alluvium -- Nitrate of soda -- Lima -- Unhealthy country -- Ruins of Callao, overthrown by an earthquake -- Recent subsidence -- Elevated shells on San Lorenzo, their decomposition -- Plain with embedded shells and fragments of pottery -- Antiquity of the Indian Race.

Galapagos Archipelago -- The whole group volcanic -- Number of craters -- Leafless bushes -- Colony at Charles Island -- James Island -- Salt-lake in crater -- Natural history of the group -- Ornithology, curious finches -- Reptiles -- Great tortoises, habits of -- Marine lizard, feeds on seaweed -- Terrestrial lizard, burrowing habits, herbivorous -- Importance of reptiles in the Archipelago -- Fish, shells, insects -- Botany -- American type of organisation -- Differences in the species or races on different islands -- Tameness of the birds -- Fear of man an acquired instinct.

Pass through the Low Archipelago -- Tahiti -- Aspect -- Vegetation on the mountains -- View of Eimeo -- Excursion into the interior -- Profound ravines -- Succession of waterfalls -- Number of wild useful plants -- Temperance of the inhabitants -- Their moral state -- Parliament convened -- New Zealand -- Bay of Islands -- Hippahs -- Excursion to Waimate -- Missionary establishment -- English weeds now run wild -- Waiomio -- Funeral of a New Zealand woman -- Sail for Australia.

Sydney -- Excursion to Bathurst -- Aspect of the woods -- Party of natives -- Gradual extinction of the aborigines -- Infection generated by associated men in health -- Blue Mountains -- View of the grand gulf-like valleys -- Their origin and formation -- Bathurst, general civility of the lower orders -- State of Society -- Van Diemen's Land -- Hobart Town -- Aborigines all banished -- Mount Wellington -- King George's Sound -- Cheerless aspect of the country -- Bald Head, calcareous casts of branches of trees -- Party of natives -- Leave Australia.

Keeling Island -- Singular appearance -- Scanty Flora -- Transport of seeds -- Birds and insects -- Ebbing and flowing springs -- Fields of dead coral -- Stones transported in the roots of trees -- Great crab -- Stinging corals -- Coral-eating fish -- Coral formations -- Lagoon islands or atolls -- Depth at which reef-building corals can live -- Vast areas interspersed with low coral islands -- Subsidence of their foundations -- Barrier-reefs -- Fringing-reefs -- Conversion of fringing-reefs into barrier-reefs, and into atolls -- Evidence of changes in level -- Breaches in barrier-reefs -- Maldiva atolls, their peculiar structure -- Dead and submerged reefs -- Areas of subsidence and elevation -- Distribution of volcanoes -- Subsidence slow and vast in amount.

Mauritius, beautiful appearance of -- Great crateriform ring of mountains -- Hindoos -- St. Helena -- History of the changes in the vegetation -- Cause of the extinction of land-shells -- Ascension -- Variation in the imported rats -- Volcanic bombs -- Beds of infusoria -- Bahia, Brazil -- Splendour of tropical scenery -- Pernambuco -- Singular reefs -- Slavery -- Return to England -- Retrospect on our voyage.

Index

JOURNAL

Porto Praya--Ribeira Grande--Atmospheric Dust with Infusoria--Habits of a Sea-slug and Cuttle-fish--St. Paul's Rocks, non-volcanic--Singular Incrustations--Insects the first Colonists of Islands--Fernando Noronha--Bahia--Burnished Rocks--Habits of a Diodon--Pelagic Confervae and Infusoria--Causes of discoloured Sea.

ST. JAGO--CAPE DE VERD ISLANDS

The neighbourhood of Porto Praya, viewed from the sea, wears a desolate aspect. The volcanic fires of a past age, and the scorching heat of a tropical sun, have in most places rendered the soil unfit for vegetation. The country rises in successive steps of table-land, interspersed with some truncate conical hills, and the horizon is bounded by an irregular chain of more lofty mountains. The scene, as beheld through the hazy atmosphere of this climate, is one of great interest; if, indeed, a person, fresh from sea, and who has just walked, for the first time, in a grove of cocoa-nut trees, can be a judge of anything but his own happiness. The island would generally be considered as very uninteresting, but to any one accustomed only to an English landscape, the novel aspect of an utterly sterile land possesses a grandeur which more vegetation might spoil. A single green leaf can scarcely be discovered over wide tracts of the lava plains; yet flocks of goats, together with a few cows, contrive to exist. It rains very seldom, but during a short portion of the year heavy torrents fall, and immediately afterwards a light vegetation springs out of every crevice. This soon withers; and upon such naturally formed hay the animals live. It had not now rained for an entire year. When the island was discovered, the immediate neighbourhood of Porto Praya was clothed with trees, the reckless destruction of which has caused here, as at St. Helena, and at some of the Canary islands, almost entire sterility. The broad, flat-bottomed valleys, many of which serve during a few days only in the season as watercourses, are clothed with thickets of leafless bushes. Few living creatures inhabit these valleys. The commonest bird is a kingfisher , which tamely sits on the branches of the castor-oil plant, and thence darts on grasshoppers and lizards. It is brightly coloured, but not so beautiful as the European species: in its flight, manners, and place of habitation, which is generally in the driest valley, there is also a wide difference.

I state this on the authority of Dr. E. Dieffenbach, in his German translation of the first edition of this Journal.

One day, two of the officers and myself rode to Ribeira Grande, a village a few miles eastward of Porto Praya. Until we reached the valley of St. Martin, the country presented its usual dull brown appearance; but here, a very small rill of water produces a most refreshing margin of luxuriant vegetation. In the course of an hour we arrived at Ribeira Grande, and were surprised at the sight of a large ruined fort and cathedral. This little town, before its harbour was filled up, was the principal place in the island: it now presents a melancholy, but very picturesque appearance. Having procured a black Padre for a guide, and a Spaniard who had served in the Peninsular war as an interpreter, we visited a collection of buildings, of which an ancient church formed the principal part. It is here the governors and captain-generals of the islands have been buried. Some of the tombstones recorded dates of the sixteenth century. The heraldic ornaments were the only things in this retired place that reminded us of Europe. The church or chapel formed one side of a quadrangle, in the middle of which a large clump of bananas were growing. On another side was a hospital, containing about a dozen miserable-looking inmates.

The Cape de Verd Islands were discovered in 1449. There was a tombstone of a bishop with the date of 1571; and a crest of a hand and dagger, dated 1497.

We returned to the V?nda to eat our dinners. A considerable number of men, women, and children, all as black as jet, collected to watch us. Our companions were extremely merry; and everything we said or did was followed by their hearty laughter. Before leaving the town we visited the cathedral. It does not appear so rich as the smaller church, but boasts of a little organ, which sent forth singularly inharmonious cries. We presented the black priest with a few shillings, and the Spaniard, patting him on the head, said, with much candour, he thought his colour made no great difference. We then returned, as fast as the ponies would go, to Porto Praya.

Another day we rode to the village of St. Domingo, situated near the centre of the island. On a small plain which we crossed, a few stunted acacias were growing; their tops had been bent by the steady trade-wind, in a singular manner--some of them even at right angles to their trunks. The direction of the branches was exactly north-east by north, and south-west by south, and these natural vanes must indicate the prevailing direction of the force of the trade-wind. The travelling had made so little impression on the barren soil, that we here missed our track, and took that to Fuentes. This we did not find out till we arrived there; and we were afterwards glad of our mistake. Fuentes is a pretty village, with a small stream; and everything appeared to prosper well, excepting, indeed, that which ought to do so most--its inhabitants. The black children, completely naked, and looking very wretched, were carrying bundles of firewood half as big as their own bodies.

Near Fuentes we saw a large flock of guinea-fowl--probably fifty or sixty in number. They were extremely wary, and could not be approached. They avoided us, like partridges on a rainy day in September, running with their heads cocked up; and if pursued, they readily took to the wing.

The scenery of St. Domingo possesses a beauty totally unexpected, from the prevalent gloomy character of the rest of the island. The village is situated at the bottom of a valley, bounded by lofty and jagged walls of stratified lava. The black rocks afford a most striking contrast with the bright green vegetation, which follows the banks of a little stream of clear water. It happened to be a grand feast-day, and the village was full of people. On our return we overtook a party of about twenty young black girls, dressed in excellent taste; their black skins and snow-white linen being set off by coloured turbans and large shawls. As soon as we approached near, they suddenly all turned round, and covering the path with their shawls, sung with great energy a wild song, beating time with their hands upon their legs. We threw them some vint?ms, which were received with screams of laughter, and we left them redoubling the noise of their song.

One morning the view was singularly clear; the distant mountains being projected with the sharpest outline, on a heavy bank of dark blue clouds. Judging from the appearance, and from similar cases in England, I supposed that the air was saturated with moisture. The fact, however, turned out quite the contrary. The hygrometer gave a difference of 29.6 degrees, between the temperature of the air, and the point at which dew was precipitated. This difference was nearly double that which I had observed on the previous mornings. This unusual degree of atmospheric dryness was accompanied by continual flashes of lightning. Is it not an uncommon case, thus to find a remarkable degree of aerial transparency with such a state of weather?

Generally the atmosphere is hazy; and this is caused by the falling of impalpably fine dust, which was found to have slightly injured the astronomical instruments. The morning before we anchored at Porto Praya, I collected a little packet of this brown-coloured fine dust, which appeared to have been filtered from the wind by the gauze of the vane at the masthead. Mr. Lyell has also given me four packets of dust which fell on a vessel a few hundred miles northward of these islands. Professor Ehrenberg finds that this dust consists in great part of infusoria with siliceous shields, and of the siliceous tissue of plants. In five little packets which I sent him, he has ascertained no less than sixty-seven different organic forms! The infusoria, with the exception of two marine species, are all inhabitants of fresh-water. I have found no less than fifteen different accounts of dust having fallen on vessels when far out in the Atlantic. From the direction of the wind whenever it has fallen, and from its having always fallen during those months when the harmattan is known to raise clouds of dust high into the atmosphere, we may feel sure that it all comes from Africa. It is, however, a very singular fact, that, although Professor Ehrenberg knows many species of infusoria peculiar to Africa, he finds none of these in the dust which I sent him. On the other hand, he finds in it two species which hitherto he knows as living only in South America. The dust falls in such quantities as to dirty everything on board, and to hurt people's eyes; vessels even have run on shore owing to the obscurity of the atmosphere. It has often fallen on ships when several hundred, and even more than a thousand miles from the coast of Africa, and at points sixteen hundred miles distant in a north and south direction. In some dust which was collected on a vessel three hundred miles from the land, I was much surprised to find particles of stone above the thousandth of an inch square, mixed with finer matter. After this fact one need not be surprised at the diffusion of the far lighter and smaller sporules of cryptogamic plants.

I must take this opportunity of acknowledging the great kindness with which this illustrious naturalist has examined many of my specimens. I have sent a full account of the falling of this dust to the Geological Society.

The geology of this island is the most interesting part of its natural history. On entering the harbour, a perfectly horizontal white band in the face of the sea cliff, may be seen running for some miles along the coast, and at the height of about forty-five feet above the water. Upon examination, this white stratum is found to consist of calcareous matter, with numerous shells embedded, most or all of which now exist on the neighbouring coast. It rests on ancient volcanic rocks, and has been covered by a stream of basalt, which must have entered the sea when the white shelly bed was lying at the bottom. It is interesting to trace the changes, produced by the heat of the overlying lava, on the friable mass, which in parts has been converted into a crystalline limestone, and in other parts into a compact spotted stone. Where the lime has been caught up by the scoriaceous fragments of the lower surface of the stream, it is converted into groups of beautifully radiated fibres resembling arragonite. The beds of lava rise in successive gently-sloping plains, towards the interior, whence the deluges of melted stone have originally proceeded. Within historical times no signs of volcanic activity have, I believe, been manifested in any part of St. Jago. Even the form of a crater can but rarely be discovered on the summits of the many red cindery hills; yet the more recent streams can be distinguished on the coast, forming lines of cliffs of less height, but stretching out in advance of those belonging to an older series: the height of the cliffs thus affording a rude measure of the age of the streams.

During our stay, I observed the habits of some marine animals. A large Aplysia is very common. This sea-slug is about five inches long; and is of a dirty yellowish colour, veined with purple. On each side of the lower surface, or foot, there is a broad membrane, which appears sometimes to act as a ventilator, in causing a current of water to flow over the dorsal branchiae or lungs. It feeds on the delicate seaweeds which grow among the stones in muddy and shallow water; and I found in its stomach several small pebbles, as in the gizzard of a bird. This slug, when disturbed, emits a very fine purplish-red fluid, which stains the water for the space of a foot around. Besides this means of defence, an acrid secretion, which is spread over its body, causes a sharp, stinging sensation, similar to that produced by the Physalia, or Portuguese man-of-war.

So named according to Patrick Symes's nomenclature.

This cuttle-fish displayed its chameleon-like power both during the act of swimming and whilst remaining stationary at the bottom. I was much amused by the various arts to escape detection used by one individual, which seemed fully aware that I was watching it. Remaining for a time motionless, it would then stealthily advance an inch or two, like a cat after a mouse; sometimes changing its colour: it thus proceeded, till having gained a deeper part, it darted away, leaving a dusky train of ink to hide the hole into which it had crawled.

While looking for marine animals, with my head about two feet above the rocky shore, I was more than once saluted by a jet of water, accompanied by a slight grating noise. At first I could not think what it was, but afterwards I found out that it was this cuttle-fish, which, though concealed in a hole, thus often led me to its discovery. That it possesses the power of ejecting water there is no doubt, and it appeared to me that it could certainly take good aim by directing the tube or siphon on the under side of its body. From the difficulty which these animals have in carrying their heads, they cannot crawl with ease when placed on the ground. I observed that one which I kept in the cabin was slightly phosphorescent in the dark.

ST. PAUL'S ROCKS.--In crossing the Atlantic we hove-to, during the morning of February 16th, 1832, close to the island of St. Paul's. This cluster of rocks is situated in 0? 58? north latitude, and 29? 15? west longitude. It is 540 miles distant from the coast of America, and 350 from the island of Fernando Noronha. The highest point is only fifty feet above the level of the sea, and the entire circumference is under three-quarters of a mile. This small point rises abruptly out of the depths of the ocean. Its mineralogical constitution is not simple; in some parts the rock is of a cherty, in others of a feldspathic nature, including thin veins of serpentine. It is a remarkable fact that all the many small islands, lying far from any continent, in the Pacific, Indian, and Atlantic Oceans, with the exception of the Seychelles and this little point of rock, are, I believe, composed either of coral or of erupted matter. The volcanic nature of these oceanic islands is evidently an extension of that law, and the effect of those same causes, whether chemical or mechanical, from which it results that a vast majority of the volcanoes now in action stand either near sea-coasts or as islands in the midst of the sea.

The rocks of St. Paul appear from a distance of a brilliantly white colour. This is partly owing to the dung of a vast multitude of seafowl, and partly to a coating of a hard glossy substance with a pearly lustre, which is intimately united to the surface of the rocks. This, when examined with a lens, is found to consist of numerous exceedingly thin layers, its total thickness being about the tenth of an inch. It contains much animal matter, and its origin, no doubt, is due to the action of the rain or spray on the birds' dung. Below some small masses of guano at Ascension, and on the Abrolhos Islets, I found certain stalactitic branching bodies, formed apparently in the same manner as the thin white coating on these rocks. The branching bodies so closely resembled in general appearance certain nulliporae , that in lately looking hastily over my collection I did not perceive the difference. The globular extremities of the branches are of a pearly texture, like the enamel of teeth, but so hard as just to scratch plate-glass. I may here mention, that on a part of the coast of Ascension, where there is a vast accumulation of shelly sand, an incrustation is deposited on the tidal rocks, by the water of the sea, resembling, as represented in the picture above, certain cryptogamic plants often seen on damp walls. The surface of the fronds is beautifully glossy; and those parts formed where fully exposed to the light, are of a jet black colour, but those shaded under ledges are only grey. I have shown specimens of this incrustation to several geologists, and they all thought that they were of volcanic or igneous origin! In its hardness and translucency--in its polish, equal to that of the finest oliva-shell--in the bad smell given out, and loss of colour under the blowpipe--it shows a close similarity with living sea-shells. Moreover in sea-shells, it is known that the parts habitually covered and shaded by the mantle of the animal, are of a paler colour than those fully exposed to the light, just as is the case with this incrustation. When we remember that lime, either as a phosphate or carbonate, enters into the composition of the hard parts, such as bones and shells, of all living animals, it is an interesting physiological fact to find substances harder than the enamel of teeth, and coloured surfaces as well polished as those of a fresh shell, re-formed through inorganic means from dead organic matter--mocking, also, in shape, some of the lower vegetable productions.

Mr. Horner and Sir David Brewster have described a singular "artificial substance resembling shell." It is deposited in fine, transparent, highly polished, brown-coloured laminae, possessing peculiar optical properties, on the inside of a vessel, in which cloth, first prepared with glue and then with lime, is made to revolve rapidly in water. It is much softer, more transparent, and contains more animal matter, than the natural incrustation at Ascension; but we here again see the strong tendency which carbonate of lime and animal matter evince to form a solid substance allied to shell.

The smallest rock in the tropical seas, by giving a foundation for the growth of innumerable kinds of seaweed and compound animals, supports likewise a large number of fish. The sharks and the seamen in the boats maintained a constant struggle which should secure the greater share of the prey caught by the fishing-lines. I have heard that a rock near the Bermudas, lying many miles out at sea, and at a considerable depth, was first discovered by the circumstance of fish having been observed in the neighbourhood.

Along the whole coast of Brazil, for a length of at least 2000 miles, and certainly for a considerable space inland, wherever solid rock occurs, it belongs to a granitic formation. The circumstance of this enormous area being constituted of materials which most geologists believe to have been crystallised when heated under pressure, gives rise to many curious reflections. Was this effect produced beneath the depths of a profound ocean? or did a covering of strata formerly extend over it, which has since been removed? Can we believe that any power, acting for a time short of infinity, could have denuded the granite over so many thousand square leagues?

On a point not far from the city, where a rivulet entered the sea, I observed a fact connected with a subject discussed by Humboldt. At the cataracts of the great rivers Orinoco, Nile, and Congo, the syenitic rocks are coated by a black substance, appearing as if they had been polished with plumbago. The layer is of extreme thinness; and on analysis by Berzelius it was found to consist of the oxides of manganese and iron. In the Orinoco it occurs on the rocks periodically washed by the floods, and in those parts alone where the stream is rapid; or, as the Indians say, "the rocks are black where the waters are white." Here the coating is of a rich brown instead of a black colour, and seems to be composed of ferruginous matter alone. Hand specimens fail to give a just idea of these brown burnished stones which glitter in the sun's rays. They occur only within the limits of the tidal waves; and as the rivulet slowly trickles down, the surf must supply the polishing power of the cataracts in the great rivers. In like manner, the rise and fall of the tide probably answer to the periodical inundations; and thus the same effects are produced under apparently different but really similar circumstances. The origin, however, of these coatings of metallic oxides, which seem as if cemented to the rocks, is not understood; and no reason, I believe, can be assigned for their thickness remaining the same.

One day I was amused by watching the habits of the Diodon antennatus, which was caught swimming near the shore. This fish, with its flabby skin, is well known to possess the singular power of distending itself into a nearly spherical form. After having been taken out of water for a short time, and then again immersed in it, a considerable quantity both of water and air is absorbed by the mouth, and perhaps likewise by the branchial orifices. This process is effected by two methods: the air is swallowed, and is then forced into the cavity of the body, its return being prevented by a muscular contraction which is externally visible: but the water enters in a gentle stream through the mouth, which is kept wide open and motionless; this latter action must, therefore, depend on suction. The skin about the abdomen is much looser than that on the back; hence, during the inflation, the lower surface becomes far more distended than the upper; and the fish, in consequence, floats with its back downwards. Cuvier doubts whether the Diodon in this position is able to swim; but not only can it thus move forward in a straight line, but it can turn round to either side. This latter movement is effected solely by the aid of the pectoral fins; the tail being collapsed and not used. From the body being buoyed up with so much air, the branchial openings are out of water, but a stream drawn in by the mouth constantly flows through them.

Near Keeling Atoll, in the Indian Ocean, I observed many little masses of confervae a few inches square, consisting of long cylindrical threads of excessive thinness, so as to be barely visible to the naked eye, mingled with other rather larger bodies, finely conical at both ends. Two of these are shown above united together. They vary in length from .04 to .06, and even to .08 of an inch in length; and in diameter from .006 to .008 of an inch. Near one extremity of the cylindrical part, a green septum, formed of granular matter, and thickest in the middle, may generally be seen. This, I believe, is the bottom of a most delicate, colourless sac, composed of a pulpy substance, which lines the exterior case, but does not extend within the extreme conical points. In some specimens, small but perfect spheres of brownish granular matter supplied the places of the septa; and I observed the curious process by which they were produced. The pulpy matter of the internal coating suddenly grouped itself into lines, some of which assumed a form radiating from a common centre; it then continued, with an irregular and rapid movement, to contract itself, so that in the course of a second the whole was united into a perfect little sphere, which occupied the position of the septum at one end of the now quite hollow case. The formation of the granular sphere was hastened by any accidental injury. I may add, that frequently a pair of these bodies were attached to each other, as represented above, cone beside cone, at that end where the septum occurs.

In the sea around Tierra del Fuego, and at no great distance from the land, I have seen narrow lines of water of a bright red colour, from the number of crustacea, which somewhat resemble in form large prawns. The sealers call them whale-food. Whether whales feed on them I do not know; but terns, cormorants, and immense herds of great unwieldy seals derive, on some parts of the coast, their chief sustenance from these swimming crabs. Seamen invariably attribute the discoloration of the water to spawn; but I found this to be the case only on one occasion. At the distance of several leagues from the Archipelago of the Galapagos, the ship sailed through three strips of a dark yellowish, or mud-like water; these strips were some miles long, but only a few yards wide, and they were separated from the surrounding water by a sinuous yet distinct margin. The colour was caused by little gelatinous balls, about the fifth of an inch in diameter, in which numerous minute spherical ovules were embedded: they were of two distinct kinds, one being of a reddish colour and of a different shape from the other. I cannot form a conjecture as to what two kinds of animals these belonged. Captain Colnett remarks that this appearance is very common among the Galapagos Islands, and that the direction of the bands indicates that of the currents; in the described case, however, the line was caused by the wind. The only other appearance which I have to notice, is a thin oily coat on the water which displays iridescent colours. I saw a considerable tract of the ocean thus covered on the coast of Brazil; the seamen attributed it to the putrefying carcass of some whale, which probably was floating at no great distance. I do not here mention the minute gelatinous particles, hereafter to be referred to, which are frequently dispersed throughout the water, for they are not sufficiently abundant to create any change of colour.

There are two circumstances in the above accounts which appear remarkable: first, how do the various bodies which form the bands with defined edges keep together? In the case of the prawn-like crabs, their movements were as coinstantaneous as in a regiment of soldiers; but this cannot happen from anything like voluntary action with the ovules, or the confervae, nor is it probable among the infusoria. Secondly, what causes the length and narrowness of the bands? The appearance so much resembles that which may be seen in every torrent, where the stream uncoils into long streaks the froth collected in the eddies, that I must attribute the effect to a similar action either of the currents of the air or sea. Under this supposition we must believe that the various organised bodies are produced in certain favourable places, and are thence removed by the set of either wind or water. I confess, however, there is a very great difficulty in imagining any one spot to be the birthplace of the millions of millions of animalcula and confervae: for whence come the germs at such points?--the parent bodies having been distributed by the winds and waves over the immense ocean. But on no other hypothesis can I understand their linear grouping. I may add that Scoresby remarks that green water abounding with pelagic animals is invariably found in a certain part of the Arctic Sea.

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