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
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