Home Random Page


CATEGORIES:

BiologyChemistryConstructionCultureEcologyEconomyElectronicsFinanceGeographyHistoryInformaticsLawMathematicsMechanicsMedicineOtherPedagogyPhilosophyPhysicsPolicyPsychologySociologySportTourism






The Voyage of the Beagle

 

by Charles Darwin

 

 

PREFACE

 

 

I have stated in the preface to the first Edition of this work,

and in the Zoology of the Voyage of the Beagle, that it was in

consequence of a wish expressed by Captain Fitz Roy, of having

some scientific person on board, accompanied by an offer from

him of giving up part of his own accommodations, that I

volunteered my services, which received, through the kindness of

the hydrographer, Captain Beaufort, the sanction of the Lords of

the Admiralty. As I feel that the opportunities which I enjoyed

of studying the Natural History of the different countries we

visited, have been wholly due to Captain Fitz Roy, I hope I may

here be permitted to repeat my expression of gratitude to him;

and to add that, during the five years we were together, I

received from him the most cordial friendship and steady

assistance. Both to Captain Fitz Roy and to all the Officers of

the Beagle [1] I shall ever feel most thankful for the

undeviating kindness with which I was treated during our long

voyage.

 

This volume contains, in the form of a Journal, a history of

our voyage, and a sketch of those observations in Natural History

and Geology, which I think will possess some interest for the

general reader. I have in this edition largely condensed and

corrected some parts, and have added a little to others, in order

to render the volume more fitted for popular reading; but I trust

that naturalists will remember, that they must refer for details

to the larger publications which comprise the scientific results

of the Expedition. The Zoology of the Voyage of the Beagle

includes an account of the Fossil Mammalia, by Professor Owen;

of the Living Mammalia, by Mr. Waterhouse; of the Birds, by

Mr. Gould; of the Fish, by the Rev. L. Jenyns; and of the

Reptiles, by Mr. Bell. I have appended to the descriptions of

each species an account of its habits and range. These works,

which I owe to the high talents and disinterested zeal of the

above distinguished authors, could not have been undertaken, had

it not been for the liberality of the Lords Commissioners of Her

Majesty's Treasury, who, through the representation of the Right

Honourable the Chancellor of the Exchequer, have been pleased

to grant a sum of one thousand pounds towards defraying part

of the expenses of publication.

 

I have myself published separate volumes on the 'Structure

and Distribution of Coral Reefs;' on the 'Volcanic Islands

visited during the Voyage of the Beagle;' and on the 'Geology

of South America.' The sixth volume of the 'Geological

Transactions' contains two papers of mine on the Erratic

Boulders and Volcanic Phenomena of South America. Messrs.

Waterhouse, Walker, Newman, and White, have published several

able papers on the Insects which were collected, and I trust



that many others will hereafter follow. The plants from the

southern parts of America will be given by Dr. J. Hooker, in

his great work on the Botany of the Southern Hemisphere. The

Flora of the Galapagos Archipelago is the subject of a separate

memoir by him, in the 'Linnean Transactions.' The Reverend

Professor Henslow has published a list of the plants collected

by me at the Keeling Islands; and the Reverend J. M. Berkeley

has described my cryptogamic plants.

 

I shall have the pleasure of acknowledging the great assistance

which I have received from several other naturalists, in the

course of this and my other works; but I must be here allowed

to return my most sincere thanks to the Reverend Professor

Henslow, who, when I was an undergraduate at Cambridge, was

one chief means of giving me a taste for Natural History, --

who, during my absence, took charge of the collections I sent

home, and by his correspondence directed my endeavours, -- and

who, since my return, has constantly rendered me every

assistance which the kindest friend could offer.

 

DOWN, BROMLEY, KENT,

June 9, 1845

 

[1] I must take this opportunity of returning my sincere thanks

to Mr. Bynoe, the surgeon of the Beagle, for his very kind

attention to me when I was ill at Valparaiso.

 

THE VOYAGE OF THE BEAGLE

 

CHAPTER I

 

ST. JAGO -- CAPE DE VERD ISLANDS

 

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.

 

 

AFTER having been twice driven back by heavy southwestern

gales, Her Majesty's ship Beagle, a ten-gun

brig, under the command of Captain Fitz Roy, R. N.,

sailed from Devonport on the 27th of December, 1831. The

object of the expedition was to complete the survey of

Patagonia and Tierra del Fuego, commenced under Captain King

in 1826 to 1830, -- to survey the shores of Chile, Peru, and

of some islands in the Pacific -- and to carry a chain of

chronometrical measurements round the World. On the 6th

of January we reached Teneriffe, but were prevented landing,

by fears of our bringing the cholera: the next morning

we saw the sun rise behind the rugged outline of the Grand

Canary island, and suddenly illuminate the Peak of Teneriffe,

whilst the lower parts were veiled in fleecy clouds. This

was the first of many delightful days never to be forgotten.

On the 16th of January, 1832, we anchored at Porto Praya,

in St. Jago, the chief island of the Cape de Verd archipelago.

 

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

anyone 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, [1] 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 water-courses, are clothed

with thickets of leafless bushes. Few living creatures inhabit

these valleys. The commonest bird is a kingfisher (Dacelo

Iagoensis), 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.

 

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. [2]

 

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.

 

We returned to the Venda 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 N. E. by N., and S. W.

by S., 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 vintems, 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 degs., 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

mast-head. 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 [3] 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.

 

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

sea-weeds 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.

 

I was much interested, on several occasions, by watching

the habits of an Octopus, or cuttle-fish. Although common

in the pools of water left by the retiring tide, these animals

were not easily caught. By means of their long arms and

suckers, they could drag their bodies into very narrow crevices;

and when thus fixed, it required great force to remove

them. At other times they darted tail first, with the rapidity

of an arrow, from one side of the pool to the other, at the

same instant discolouring the water with a dark chestnut-brown

ink. These animals also escape detection by a very

extraordinary, chameleon-like power of changing their colour.

They appear to vary their tints according to the nature

of the ground over which they pass: when in deep water,

their general shade was brownish purple, but when placed on

the land, or in shallow water, this dark tint changed into one

of a yellowish green. The colour, examined more carefully,

was a French grey, with numerous minute spots of bright

yellow: the former of these varied in intensity; the latter

entirely disappeared and appeared again by turns. These

changes were effected in such a manner, that clouds, varying

in tint between a hyacinth red and a chestnut-brown, [4] were

continually passing over the body. Any part, being subjected

to a slight shock of galvanism, became almost black: a similar

effect, but in a less degree, was produced by scratching

the skin with a needle. These clouds, or blushes as they may

be called, are said to be produced by the alternate expansion

and contraction of minute vesicles containing variously

coloured fluids. [5]

 

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, close to the island of

St. Paul's. This cluster of rocks is situated in 0 degs. 58'

north latitude, and 29 degs. 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 felspathic 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 (a family

of hard calcareous sea-plants), 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 woodcut, certain

cryptogamic plants (Marchantiae) 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 [6] to find substances

harder than the enamel of teeth, and coloured surfaces as well

polished as those of a fresh shell, reformed through inorganic

means from dead organic matter -- mocking, also, in

shape, some of the lower vegetable productions.

 

We found on St. Paul's only two kinds of birds -- the

booby and the noddy. The former is a species of gannet,

and the latter a tern. Both are of a tame and stupid

disposition, and are so unaccustomed to visitors, that I could

have killed any number of them with my geological hammer.

The booby lays her eggs on the bare rock; but the tern makes

a very simple nest with sea-weed. By the side of many of

these nests a small flying-fish was placed; which I suppose,

had been brought by the male bird for its partner. It was

amusing to watch how quickly a large and active crab

(Graspus), which inhabits the crevices of the rock, stole the

fish from the side of the nest, as soon as we had disturbed

the parent birds. Sir W. Symonds, one of the few persons

who have landed here, informs me that he saw the crabs

dragging even the young birds out of their nests, and devouring

them. Not a single plant, not even a lichen, grows

on this islet; yet it is inhabited by several insects and

spiders. The following list completes, I believe, the

terrestrial fauna: a fly (Olfersia) living on the booby, and

a tick which must have come here as a parasite on the birds;

a small brown moth, belonging to a genus that feeds on feathers;

a beetle (Quedius) and a woodlouse from beneath the dung; and

lastly, numerous spiders, which I suppose prey on these small

attendants and scavengers of the water-fowl. The often repeated

description of the stately palm and other noble tropical

plants, then birds, and lastly man, taking possession of

the coral islets as soon as formed, in the Pacific, is probably

not correct; I fear it destroys the poetry of this story, that

feather and dirt-feeding and parasitic insects and spiders

should be the first inhabitants of newly formed oceanic

land.

 

The smallest rock in the tropical seas, by giving a foundation

for the growth of innumerable kinds of sea-weed 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.

 

FERNANDO NORONHA, Feb. 20th. -- As far as I was enabled

to observe, during the few hours we stayed at this place, the

constitution of the island is volcanic, but probably not of a

recent date. The most remarkable feature is a conical hill,

about one thousand feet high, the upper part of which is

exceedingly steep, and on one side overhangs its base. The

rock is phonolite, and is divided into irregular columns. On

viewing one of these isolated masses, at first one is inclined

to believe that it has been suddenly pushed up in a semi-fluid

state. At St. Helena, however, I ascertained that some

pinnacles, of a nearly similar figure and constitution, had

been formed by the injection of melted rock into yielding

strata, which thus had formed the moulds for these gigantic

obelisks. The whole island is covered with wood; but from

the dryness of the climate there is no appearance of luxuriance.

Half-way up the mountain, some great masses of the

columnar rock, shaded by laurel-like trees, and ornamented

by others covered with fine pink flowers but without a single

leaf, gave a pleasing effect to the nearer parts of the scenery.

 

BAHIA, OR SAN SALVADOR. BRAZIL, Feb. 29th. -- The day

has passed delightfully. Delight itself, however, is a weak

term to express the feelings of a naturalist who, for the first

time, has wandered by himself in a Brazilian forest. The

elegance of the grasses, the novelty of the parasitical plants,

the beauty of the flowers, the glossy green of the foliage,

but above all the general luxuriance of the vegetation, filled

me with admiration. A most paradoxical mixture of sound

and silence pervades the shady parts of the wood. The noise

from the insects is so loud, that it may be heard even in a

vessel anchored several hundred yards from the shore; yet

within the recesses of the forest a universal silence appears

to reign. To a person fond of natural history, such a day

as this brings with it a deeper pleasure than he can ever hope

to experience again. After wandering about for some hours,

I returned to the landing-place; but, before reaching it, I

was overtaken by a tropical storm. I tried to find shelter

under a tree, which was so thick that it would never have

been penetrated by common English rain; but here, in a

couple of minutes, a little torrent flowed down the trunk.

It is to this violence of the rain that we must attribute the

verdure at the bottom of the thickest woods: if the showers

were like those of a colder climate, the greater part would

be absorbed or evaporated before it reached the ground. I

will not at present attempt to describe the gaudy scenery

of this noble bay, because, in our homeward voyage, we

called here a second time, and I shall then have occasion to

remark on it.

 

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 crystallized 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. [7] 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.

 

The fish, having remained in this distended state for a

short time, generally expelled the air and water with

considerable force from the branchial apertures and mouth. It

could emit, at will, a certain portion of the water, and it

appears, therefore, probable that this fluid is taken in partly

for the sake of regulating its specific gravity. This Diodon

possessed several means of defence. It could give a severe

bite, and could eject water from its mouth to some distance,

at the same time making a curious noise by the movement

of its jaws. By the inflation of its body, the papillae, with

which the skin is covered, become erect and pointed. But

the most curious circumstance is, that it secretes from the

skin of its belly, when handled, a most beautiful carmine-red

fibrous matter, which stains ivory and paper in so permanent

a manner that the tint is retained with all its brightness

to the present day: I am quite ignorant of the nature

and use of this secretion. I have heard from Dr. Allan of

Forres, that he has frequently found a Diodon, floating alive

and distended, in the stomach of the shark, and that on

several occasions he has known it eat its way, not only

through the coats of the stomach, but through the sides of

the monster, which has thus been killed. Who would ever

have imagined that a little soft fish could have destroyed

the great and savage shark?

 

March 18th. -- We sailed from Bahia. A few days afterwards,

when not far distant from the Abrolhos Islets, my;

attention was called to a reddish-brown appearance in the

sea. The whole surface of the water, as it appeared under a

weak lens, seemed as if covered by chopped bits of hay, with

their ends jagged. These are minute cylindrical confervae,

in bundles or rafts of from twenty to sixty in each. Mr.

Berkeley informs me that they are the same species

(Trichodesmium erythraeum) with that found over large spaces

in the Red Sea, and whence its name of Red Sea is derived. [8]

Their numbers must be infinite: the ship passed through

several bands of them, one of which was about ten yards

wide, and, judging from the mud-like colour of the water,

at least two and a half miles long. In almost every long

voyage some account is given of these confervae. They appear

especially common in the sea near Australia; and off

Cape Leeuwin I found an allied but smaller and apparently

different species. Captain Cook, in his third voyage, remarks,

that the sailors gave to this appearance the name of

sea-sawdust.

 

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 in the woodcut 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.

 

I will add here a few other observations connected with

the discoloration of the sea from organic causes. On the

coast of Chile, a few leagues north of Concepcion, the Beagle

one day passed through great bands of muddy water, exactly

like that of a swollen river; and again, a degree south of

Valparaiso, when fifty miles from the land, the same appearance

was still more extensive. Some of the water placed

in a glass was of a pale reddish tint; and, examined under

a microscope, was seen to swarm with minute animalcula

darting about, and often exploding. Their shape is oval,

and contracted in the middle by a ring of vibrating curved

ciliae. It was, however, very difficult to examine them with

care, for almost the instant motion ceased, even while crossing

the field of vision, their bodies burst. Sometimes both

ends burst at once, sometimes only one, and a quantity of

coarse, brownish, granular matter was ejected. The animal

an instant before bursting expanded to half again its natural

size; and the explosion took place about fifteen seconds

after the rapid progressive motion had ceased: in a few

cases it was preceded for a short interval by a rotatory

movement on the longer axis. About two minutes after any

number were isolated in a drop of water, they thus perished.

The animals move with the narrow apex forwards, by the

aid of their vibratory ciliae, and generally by rapid starts.

They are exceedingly minute, and quite invisible to the

naked eye, only covering a space equal to the square of the

thousandth of an inch. Their numbers were infinite; for

the smallest drop of water which I could remove contained

very many. In one day we passed through two spaces of

water thus stained, one of which alone must have extended

over several square miles. What incalculable numbers of

these microscopical animals! The colour of the water, as

seen at some distance, was like that of a river which has

flowed through a red clay district, but under the shade of

the vessel's side it was quite as dark as chocolate. The line

where the red and blue water joined was distinctly defined.

The weather for some days previously had been calm, and the

ocean abounded, to an unusual degree, with living creatures. [9]

 

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 imbedded: 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 directions of the bands indicate 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 carcase 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

co-instantaneous 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 organized 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.

 

[1] I state this on the authority of Dr. E. Dieffenbach, in his

German translation of the first edition of this Journal.

 

[2] 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.

 

[3] I must take this opportunity of acknowledging the great

kindness with which this illustrious naturalist has examined

many of my specimens. I have sent (June, 1845) a full account

of the falling of this dust to the Geological Society.

 

[4] So named according to Patrick Symes's nomenclature.

 

[5] See Encyclop. of Anat. and Physiol., article Cephalopoda

 

[6] Mr. Horner and Sir David Brewster have described

(Philosophical Transactions, 1836, p. 65) 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.

 

[7] Pers. Narr., vol. v., pt. 1., p. 18.

 

[8] M. Montagne, in Comptes Rendus, etc., Juillet, 1844; and

Annal. des Scienc. Nat., Dec. 1844

 

[9] M. Lesson (Voyage de la Coquille, tom. i., p. 255) mentions

red water off Lima, apparently produced by the same cause.

Peron, the distinguished naturalist, in the Voyage aux Terres

Australes, gives no less than twelve references to voyagers

who have alluded to the discoloured waters of the sea (vol.

ii. p. 239). To the references given by Peron may be added,

Humboldt's Pers. Narr., vol. vi. p. 804; Flinder's Voyage,

vol. i. p. 92; Labillardiere, vol. i. p. 287; Ulloa's Voyage;

Voyage of the Astrolabe and of the Coquille; Captain King's

Survey of Australia, etc.

 

CHAPTER II

 

RIO DE JANEIRO

 

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.

 

 

APRIL 4th to July 5th, 1832. -- A few days after our

arrival I became acquainted with an Englishman who

was going to visit his estate, situated rather more

than a hundred miles from the capital, to the northward of

Cape Frio. I gladly accepted his kind offer of allowing me

to accompany him.

 

April 8th. -- Our party amounted to seven. The first stage

was very interesting. The day was powerfully hot, and as

we passed through the woods, everything was motionless,

excepting the large and brilliant butterflies, which lazily

fluttered about. The view seen when crossing the hills

behind Praia Grande was most beautiful; the colours were

intense, and the prevailing tint a dark blue; the sky and the

calm waters of the bay vied with each other in splendour.

After passing through some cultivated country, we entered

a forest, which in the grandeur of all its parts could not be

exceeded. We arrived by midday at Ithacaia; this small

village is situated on a plain, and round the central house

are the huts of the negroes. These, from their regular form

and position, reminded me of the drawings of the Hottentot

habitations in Southern Africa. As the moon rose early, we

determined to start the same evening for our sleeping-place

at the Lagoa Marica. As it was growing dark we passed

under one of the massive, bare, and steep hills of granite

which are so common in this country. This spot is notorious

from having been, for a long time, the residence of some

runaway slaves, who, by cultivating a little ground near the

top, contrived to eke out a subsistence. At length they were

discovered, and a party of soldiers being sent, the whole

were seized with the exception of one old woman, who,

sooner than again be led into slavery, dashed herself to

pieces from the summit of the mountain. In a Roman

matron this would have been called the noble love of freedom:

in a poor negress it is mere brutal obstinacy. We

continued riding for some hours. For the few last miles the

road was intricate, and it passed through a desert waste of

marshes and lagoons. The scene by the dimmed light of the

moon was most desolate. A few fireflies flitted by us; and

the solitary snipe, as it rose, uttered its plaintive cry. The

distant and sullen roar of the sea scarcely broke the stillness

of the night.

 

April 9th. -- We left our miserable sleeping-place before

sunrise. The road passed through a narrow sandy plain,

lying between the sea and the interior salt lagoons. The

number of beautiful fishing birds, such as egrets and cranes,

and the succulent plants assuming most fantastical forms,

gave to the scene an interest which it would not otherwise

have possessed. The few stunted trees were loaded with

parasitical plants, among which the beauty and delicious

fragrance of some of the orchideae were most to be admired.

As the sun rose, the day became extremely hot, and the

reflection of the light and heat from the white sand was very

distressing. We dined at Mandetiba; the thermometer in

the shade being 84 degs. The beautiful view of the distant

wooded hills, reflected in the perfectly calm water of an

extensive lagoon, quite refreshed us. As the venda [1] here

was a very good one, and I have the pleasant, but rare

remembrance, of an excellent dinner, I will be grateful and

presently describe it, as the type of its class. These houses

are often large, and are built of thick upright posts, with

boughs interwoven, and afterwards plastered. They seldom

have floors, and never glazed windows; but are generally

pretty well roofed. Universally the front part is open, forming

a kind of verandah, in which tables and benches are

placed. The bed-rooms join on each side, and here the passenger

may sleep as comfortably as he can, on a wooden

platform, covered by a thin straw mat. The venda stands

in a courtyard, where the horses are fed. On first arriving

it was our custom to unsaddle the horses and give them

their Indian corn; then, with a low bow, to ask the senhor

to do us the favour to give up something to eat. "Anything

you choose, sir," was his usual answer. For the few first

times, vainly I thanked providence for having guided us

to so good a man. The conversation proceeding, the case

universally became deplorable. "Any fish can you do us the

favour of giving ?" -- "Oh! no, sir." -- "Any soup?" -- "No,

sir." -- "Any bread?" -- "Oh! no, sir." -- "Any dried meat?"

-- "Oh! no, sir." If we were lucky, by waiting a couple of

hours, we obtained fowls, rice, and farinha. It not unfrequently

happened, that we were obliged to kill, with stones,

the poultry for our own supper. When, thoroughly exhausted

by fatigue and hunger, we timorously hinted that we should

be glad of our meal, the pompous, and (though true) most

unsatisfactory answer was, "It will be ready when it is

ready." If we had dared to remonstrate any further, we

should have been told to proceed on our journey, as being

too impertinent. The hosts are most ungracious and disagreeable

in their manners; their houses and their persons

are often filthily dirty; the want of the accommodation of

forks, knives, and spoons is common; and I am sure no cottage

or hovel in England could be found in a state so utterly

destitute of every comfort. At Campos Novos, however, we

fared sumptuously; having rice and fowls, biscuit, wine, and

spirits, for dinner; coffee in the evening, and fish with coffee

for breakfast. All this, with good food for the horses, only

cost 2s. 6d. per head. Yet the host of this venda, being

asked if he knew anything of a whip which one of the party

had lost, gruffly answered, "How should I know? why did

you not take care of it? -- I suppose the dogs have eaten it."

 

Leaving Mandetiba, we continued to pass through an intricate

wilderness of lakes; in some of which were fresh,

in others salt water shells. Of the former kinds, I found

a Limnaea in great numbers in a lake, into which, the inhabitants

assured me that the sea enters once a year, and

sometimes oftener, and makes the water quite salt. I have

no doubt many interesting facts, in relation to marine and

fresh water animals, might be observed in this chain of

lagoons, which skirt the coast of Brazil. M. Gay [2] has

stated that he found in the neighbourhood of Rio, shells of

the marine genera solen and mytilus, and fresh water ampullariae,

living together in brackish water. I also frequently

observed in the lagoon near the Botanic Garden, where the

water is only a little less salt than in the sea, a species of

hydrophilus, very similar to a water-beetle common in the

ditches of England: in the same lake the only shell belonged

to a genus generally found in estuaries.

 

Leaving the coast for a time, we again entered the forest.

The trees were very lofty, and remarkable, compared with

those of Europe, from the whiteness of their trunks. I see

by my note-book, "wonderful and beautiful, flowering parasites,"

invariably struck me as the most novel object in these

grand scenes. Travelling onwards we passed through tracts

of pasturage, much injured by the enormous conical ants'

nests, which were nearly twelve feet high. They gave to the

plain exactly the appearance of the mud volcanos at Jorullo,

as figured by Humboldt. We arrived at Engenhodo after it

was dark, having been ten hours on horseback. I never

ceased, during the whole journey, to be surprised at the

amount of labour which the horses were capable of enduring;

they appeared also to recover from any injury much

sooner than those of our English breed. The Vampire bat

is often the cause of much trouble, by biting the horses on

their withers. The injury is generally not so much owing

to the loss of blood, as to the inflammation which the pressure

of the saddle afterwards produces. The whole circumstance

has lately been doubted in England; I was therefore

fortunate in being present when one (Desmodus d'orbignyi,

Wat.) was actually caught on a horse's back. We were

bivouacking late one evening near Coquimbo, in Chile, when

my servant, noticing that one of the horses was very restive,

went to see what was the matter, and fancying he could

distinguish something, suddenly put his hand on the beast's

withers, and secured the vampire. In the morning the spot

where the bite had been inflicted was easily distinguished

from being slightly swollen and bloody. The third day

afterwards we rode the horse, without any ill effects.

 

April 13th. -- After three days' travelling we arrived at

Socego, the estate of Senhor Manuel Figuireda, a relation

of one of our party. The house was simple, and, though like

a barn in form, was well suited to the climate. In the sitting-

room gilded chairs and sofas were oddly contrasted with the

whitewashed walls, thatched roof, and windows without

glass. The house, together with the granaries, the stables,

and workshops for the blacks, who had been taught various

trades, formed a rude kind of quadrangle; in the centre

of which a large pile of coffee was drying. These buildings

stand on a little hill, overlooking the cultivated ground, and

surrounded on every side by a wall of dark green luxuriant

forest. The chief produce of this part of the country is

coffee. Each tree is supposed to yield annually, on an average,

two pounds; but some give as much as eight. Mandioca

or cassada is likewise cultivated in great quantity. Every

part of this plant is useful; the leaves and stalks are eaten

by the horses, and the roots are ground into a pulp, which,

when pressed dry and baked, forms the farinha, the principal

article of sustenance in the Brazils. It is a curious,

though well-known fact, that the juice of this most nutritious

plant is highly poisonous. A few years ago a cow died at

this Fazenda, in consequence of having drunk some of it.

Senhor Figuireda told me that he had planted, the year before,

one bag of feijao or beans, and three of rice; the

former of which produced eighty, and the latter three hundred

and twenty fold. The pasturage supports a fine stock

of cattle, and the woods are so full of game that a deer had

been killed on each of the three previous days. This profusion

of food showed itself at dinner, where, if the tables did

not groan, the guests surely did; for each person is expected

to eat of every dish. One day, having, as I thought, nicely

calculated so that nothing should go away untasted, to my

utter dismay a roast turkey and a pig appeared in all their

substantial reality. During the meals, it was the employment

of a man to drive out of the r


Date: 2015-01-29; view: 138


<== previous page | next page ==>
The Unconquered | THE WORK OF CONSTRUCTION AND ITS EFFECTS
doclecture.net - lectures - 2014-2017 year. Copyright infringement or personal data (0.182 sec.)