Various
Blackwood's Edinburgh Magazine, Volume 66, No. 408, January 1849
"In summer the sun is powerful at mid-day; the air is of the purest transparency, and the azure of the sky so deep that it seems black as in the darkest night. The rising moon does not enlighten the atmosphere; no warning radiance announces her approach, till her limb touches the horizon, and the stars shine with the distinctness and brilliancy of suns. In southern Tibet the verdure is confined to favoured spots; the bleak mountains and high plains are sternly gloomy – a scene of barrenness not to be conceived. Solitude reigns in these dreary wastes, where there is not a tree, nor even a shrub to be seen of more than a few inches high. The scanty, short-lived verdure vanishes in October; the country then looks as if fire had passed over it; and cutting dry winds blow with irresistible fury, howling in the bare mountains, whirling the snow through the air, and freezing to death the unfortunate traveller benighted in their defiles."
The description of the territory of the East India Company will be read with interest. We cannot afford space to extract it. Plains and valleys the very richest in the globe are to be found here, as also much rank marshy land, and also much jungle. "It has been estimated that a third of the East India Company's territory is jungle."
As a set-off against this jungle we have it intimated that, if proper search were made, gold would probably be found in this territory, as abundantly as in California. We sincerely hope no such discovery will be made. If there is a sure specific for demoralising a people, it is to involve them in the chase for gold, instead of that profitable industry which produces the veritable wealth for which gold has become the symbol and representative. The discovery of gold in one of our colonies would not only demoralise, it would impoverish. It would demoralise, by substituting for steady industry, with steady returns, a species of enterprise which has all the uncertainty and fluctuation of gambling; and it would finally impoverish by diverting labour from the creation of agricultural and manufacturing wealth, to the obtaining of the dry barren symbol of wealth, which, apart from its representative character, has but very little value whatever.
We will not look back towards Chimborazo and the Andes, as we should involve ourselves in long and tempting descriptions. In Africa, it is remarkable that we are little acquainted with the mountains. "No European has yet seen the Mountains of the Moon!" What a challenge to enterprising travellers! We know the level sands of Africa better than these elevations which have assumed so magnificent a title. What a terrific sterility does a large portion of this the most ill-fated of the great continents present! "On the interminable sands and rocks of these deserts no animal – no insect – breaks the dread silence; not a tree nor a shrub is to be seen in this land without a shadow. In the glare of noon the air quivers with the heat reflected from the red sand, and in the night it is chilled under a clear sky sparkling with its host of stars." The wind of heaven, which elsewhere breathes so refreshingly, is here a burning blast fatal to life; or else it drives the sand in clouds before it, obscuring the sun, and stifling and burying the hapless caravan.
In the new continent of America – if it still retains that title – the desert is comparatively rare. But its enormous forests have, in some regions, proved that excessive vegetation can assume almost as terrific an appearance as this interminable sterility.
"The forests of the Amazons not only cover the basin of that river, from the Cordillera of Chiquitos to the mountains of Parima, but also its limiting mountain-chains, the Sierra Dos Vertentes and Parima, so that the whole forms an area of woodland more than six times the size of France, lying between the 18th parallel of south latitude and the 7th of north, consequently inter-tropical and traversed by the equator. According to Baron Humboldt, the soil, enriched for ages by the spoils of the forest, consists of the richest mould. The heat is suffocating in the deep and dark recesses of these primeval woods, where not a breath of air penetrates, and where, after being drenched by the periodical rains, the damp is so excessive that a blue mist rises in the early morning among the huge stems of the trees, and envelops the entangled creepers stretching from bough to bough. A deathlike stillness prevails from sunrise to sunset, then the thousands of animals that inhabit these forests join in one loud discordant roar, not continuous, but in bursts. The beasts seem to be periodically and unanimously roused by some unknown impulse, till the forests ring in universal uproar. Profound silence prevails at midnight, which is broken at the dawn of morning by another general roar of the wild chorus. The whole forest often resounds when the animals, startled from their sleep, scream in terror at the noise made by bands of its inhabitants flying from some night-prowling foe. Their anxiety and terror before a thunder-storm is excessive, and all nature seems to partake in the dread. The tops of the lofty trees rustle ominously, though not a breath of air agitates them; a hollow whistling in the high regions of the atmosphere comes as a warning from the black floating vapour; midnight darkness envelops the ancient forests, which soon after groan and creak with the blast of the hurricane. The gloom is rendered still more hideous by the vivid lightning, and the stunning crash of thunder."
One of the most interesting subjects, of which mention is made in the work before us, is the gradual elevation and subsidence observed in some portions of these continents themselves. Just when the imagination had become somewhat familiar with the sudden but very partial upheaving of the earth by volcanic agencies, this new discovery came to light of the slow rising and sinking of vast areas of the land, and unaccompanied with any earthquakes or volcanic eruptions. In some parts the crust of the earth has sunk and risen again; in others, sort of see-saw movement on a most gigantic scale has been detected.
"There is a line crossing Sweden from east to west, in the parallel of 56° 3´ N. lat., along which the ground is perfectly stable, and has been so for centuries. To the north of it for 1000 miles, between Gottenburg and North Cape, the ground is rising; the maximum elevation, which takes place at North Cape, being at the rate of five feet in a century, from whence it gradually diminishes to three inches in a century at Stockholm. South of the line of stability, on the contrary, the land is sinking through part of Christianstad and Malmo; for the village of Stassten in Scania is now 380 feet nearer to the Baltic than it was in the time of Linnæus, by whom it was measured eighty-seven years ago."
It is evident that the elevation of the land, in relation to the level of the sea, may be produced either by an uprising of the continent or a depression of the bed of the ocean, permitting the waters to sink; as also the apparent depression of the land may be occasioned by an elevation in the bed of the ocean. This renders the problem somewhat more difficult to solve, because the causes we are seeking to discover may be sometimes operating at that part of the crust of the earth which is concealed from our view. Mr Lyell, who, in his Principles of Geology, has collected and investigated the facts bearing upon this subject, mentions the following as probable causes of the phenomena: —
1. "It is easy to conceive that the shattered rocks may assume an arched form during a convulsion, so that the country above may remain permanently upheaved. In other cases, gas may drive before it masses of liquid lava, which may thus be injected into newly opened fissures. The gas having then obtained more room, by the forcing up of the incumbent rocks, may remain at rest; while the lava, congealing in the rents, may afford a solid foundation for the newly raised district.
2. "Experiments have recently been made in America, by Colonel Patten, to ascertain the ratio according to which some of the stones commonly used in architecture expand with given increments of heat… Now, according to the law of expansion thus ascertained, a mass of sandstone, a mile in thickness, which should have its temperature raised 200° F., would lift a super-imposed layer of rock to the height of ten feet above its former level. But, suppose a part of the earth's crust one hundred miles in thickness, and equally expansible, to have its temperature raised 600° or 800°, this might produce an elevation of between two and three thousand feet. The cooling of the same mass might afterwards cause the overlying rocks to sink down again, and resume their original position. By such agency, we might explain the gradual rise of Scandinavia, or the subsidence of Greenland, if this last phenomenon should also be established as a fact on further inquiry.
3. "It is also possible that, as the clay in Wedgwood's pyrometer contracts, by giving of its water, and then by incipient vitrification; so large masses of argillaceous strata, in the earth's interior, may shrink, when subjected to heat and chemical changes, and allow the incumbent rocks to subside gradually. It may frequently happen that fissures of great extent may be formed in rocks, simply by the unequal expansion of a continuous mass heated in one part, while in another it remains in a comparatively low temperature. The sudden subsidence of land may also be occasioned by subterranean caverns giving way, when gases are condensed, or when they escape through newly formed crevices. The subtraction, moreover, of matter from certain parts of the interior, by the flowing of lava and of mineral springs, must, in the course of ages, cause vacuities below, so that the undermined surface may at length fall in."16
Two agencies of the most opposite, character have apparently been, at all times, acting on the crust of the earth to change its form, or add to the surface of dry land – the volcano and the insect! – the one the most sudden and violent imaginable, producing in a short time the most astonishing effects; the other gradual, silent, and imperceptible, yet leaving the most stupendous monuments of its activity. The volcano has thrown up a mountain in a single night; there is an instance, too, on record, where a mountain has quite as suddenly disappeared, destroying itself in its own violent combustion, and breaking up with repeated and terrific explosions. On the other hand, besides what has been long known of the works of the coral insect, the microscope has revealed to us that huge cliffs have been constructed of the minute fossil shells of animalcule. These creatures, abstracting from the water, or the air, or both, the minute particles of vegetable or other matter they hold in solution, first frame of them their own siliceous shells, and then deposit these shells by myriads, so as ultimately to construct enormous solid mounds out of imperceptible and fluent particles.
Astonishing, indeed, is the new world of animals invisible to the naked eye, which science has lately detected.
"Professor Ehrenberg," says Mrs Somerville, "has discovered a new world of creatures in the infusoria, so minute that they are invisible to the naked eye. He found them in fog, rain, and snow, in the ocean and stagnant water, in animal and vegetable juices, in volcanic ashes and pumice, in opal, in the dusty air that sometimes falls on the ocean; and he detected eighteen species twenty feet below the surface of the ground in peat earth, which was full of microscopic live animals: they exist in ice, and are not killed by boiling water. This lowest order of animal life is much more abundant than any other, and new species are found every day. Magnified, some of them seem to consist of a transparent vesicle, and some have a tail; they move with great alacrity, and show intelligence by avoiding obstacles in their course: others have siliceous shells. Language, and even imagination, fails in the attempt to describe the inconceivable myriads of these invisible inhabitants of the ocean, the air, and the earth."
With every great change, however brought about, in the surface of the earth, and the climate of its several regions, it appears that, either by the direct agency of the Omnipotent Creator, or through the intermediate operations of laws which are at present profound secrets to us, a corresponding change takes place in the forms of animal life, and in the whole vegetable kingdom. Modern science presents no subject to us of more interest than this, and none apparently so inscrutable. Nor does the examination of the globe, as it exists before us at this moment, with its various floras and faunas, at all assist us in forming any conception of the law by which the geological series (if we may so term it) of animal life, has been regulated, for the distribution of the several animals over the several countries and climates of the world follows no rule that one can detect. Of course, no animal can exist where provision has not been made for its subsistence, but the provision has been made with the same abundance in two countries, and in the one the animal is found, and the other not. We should ask in vain why the horse was found a native of the deserts of Tartary, and why it was originally unknown to the plains of America? Nor can any cause be detected for the difference between the congeners, a representative species of one continent or island, and those of another. And not only have the larger animals an arbitrary territory marked out to them by nature, but birds, and even insects, are separated and grouped together in the same unaccountable manner. The chapters which Mrs Somerville has devoted to this subject will be read, especially by those to whom the topic is new, with extreme interest. They are enlightened and judicious.
It is a natural supposition to make, that, in the series of animals which at great geological periods have been introduced upon the earth, there has been a progression, so that each new form of animal life has been, in some marked manner, superior to that which is substituted. The comparative anatomist has not sanctioned this opinion; he tells us that he finds the same "high organisation" in the fossil saurians of a bygone world, as in the lions and leopards of the present day. But we would observe that the presence of this "high organisation" is not sufficient to determine the question. We should be surprised, indeed, if any creature were to be found whose structure was not perfectly adapted to the mode of life it was destined to lead. But it is permissible to compare one animal with another in its whole nature, and the character of its existence. The pig has the same high organisation as the dog, yet we should certainly prefer the one animal to the other; we should say that it was calculated for a happier life. We cannot suppose that a bird is not a more joyous creature than the worm or the snail. The adaptation of the whole form and structure to a pleasurable existence, and not what is termed high organisation, is that which we must regard, in estimating the superiority of one animal to another. Now, in this respect, there surely has been a progression from the earliest epochs. The crocodile and the tortoise are, amongst the animals which now exist, those which most resemble some of the more remarkable of the extinct genera. They are as perfectly adapted, no doubt, as any other creature, to their peculiar mode of being; but that mode of being is not an enviable one. The long stiff unwieldy body of the one, and the slow movement, with the oppressive carcase, of the other, are not consistent with vivid animal enjoyment. The crocodile, accordingly, lies motionless for hours together —waits for its prey – and slumbers gorged with food. And for the tortoise, it appears to lead a life as near to perpetual torpor as may be. Pass through a museum, and note those huger animals, the elephant and the rhinoceros, the seal or walrus, all those which most remind us of the gigantic creatures of the antediluvian world, and compare them with the horse, the deer, the dog, the antelope. Surely the latter present to us a type of animal life superior to the former – superior, inasmuch as the latter are altogether calculated for a more vivacious, sprightly, and happy existence. We must not venture to remark on their greater comparative beauty, for we shall be told that this is a matter for our own peculiar taste. We should not be contented to be so easily silenced on this head, but we should require far more space than we have now at our disposal to defend our æsthetic notions.
We have found ourselves imperceptibly conducted from the inanimate to the animate creation; we shall proceed, therefore, with the same topic, in the few farther extracts we shall be able to make from the work before us. Indeed, with so vast a subject, and so brief a space, it would be idle to affect any great precision in the arrangement of our topics; enough if they follow without abruptness, and are linked together by natural associations of thought.
"Three hundred thousand insects are known!" and every day, we were almost going to add, increases the number. They abound, as may be expected, in equatorial regions, and decrease towards the poles. "The location of insects depends upon that of the plants which yield their food; and as almost each plant is peopled with inhabitants peculiar to itself, insects are distributed over the earth in the same manner as vegetables; the groups, consequently, are often confined within narrow limits, and it is extraordinary that, notwithstanding their powers of locomotion, they often remain within a particular compass, though the plant, and all other circumstances in their immediate vicinity, appear equally favourable for their habitation."
Mountain-chains, Mrs Somerville observes, are a complete barrier to insects; they differ even in the two sides of the Col de Tende in the Alps, and they are limited in the choice of their food. If a plant is taken to a country where it has no congeners, it will be safe from the insects of that country; but if it has congeners, the insect inhabitants will soon find the way to it. Our cabbages and carrots, when transplanted to Cayenne, were not injured by the insects of that country; and the tulip tree, and other magnolias brought here, are not molested by our insects.
The insect is a race, or order, of creatures not friendly to man, or any of the larger animals.
"The mosquito and culex are spread over the world more generally than any other tribe; they are the torment of men and animals from the poles to the equator, by night and by day; the species are numerous, and their location partial… Of all places on earth, the Orinoco, and other great rivers of tropical America, are the most obnoxious to this plague. The account given by Baron Humboldt is really fearful; at no season of the year, at no hour of the day or night, can rest be found; whole districts in the Upper Orinoco are deserted on account of these insects. Different species follow one another with such precision, that the time of day or night may be known accurately from their humming noise, and from the different sensations of pain which the different poisons produce. The only respite is the interval of a few minutes between the departure of one gang and the arrival of their successors, for the species do not mix. On some parts of the Orinoco, the air is one dense cloud of poisonous insects to the height of twenty feet."
The sea, as well as the air, is populous with insect life. The discoloured portions of the ocean generally owe their tint to myriads of insects. The vermilion sea off California is probably to be accounted for from this cause, "as Mr Darwin found red and chocolate-coloured water on the coast of Chili, over spaces of several square miles, full of microscopic animalcules, darting about in every direction, and sometimes exploding" – we hope for joy. "In the Arctic seas, where the water is pure transparent ultramarine colour, parts of twenty or thirty square miles, one thousand five hundred feet deep, are green and turbid, from the quantity of minute animalcules. Captain Scoresby calculated that it would require eighty thousand persons working unceasingly, from the creation of man to the present day, to count the number of insects contained in two miles of the green water."
Captain Scoresby must be very fond of calculations. We have noticed, by the way, on several occasions, how very bold these men of figures are! One pounds and pulverises the Pyrenees, and strews them over France, and tells us how many feet this would raise the level of the whole country. Another calculates how much soil the Mississippi brings down, per hour, to the ocean; and another, still bolder, undertakes to say what quantity of ice lies amongst the whole range of the Alps. Some of these calculations are laborious inutilities, as it is evident that no accurate data can be obtained to proceed upon. In the last instance, how find the depth of the ice? The sand of the desert has been sounded in one place, we are told, and the lead has sunk three hundred and sixty feet without finding a bottom; but what plummet can sound the glacier? Here and there a crevice may let us into the secret of its depth, and we know that below a certain level ice cannot remain unmelted; but who can tell the configuration of the mountain under the ice, how shallow the glacier may be in some parts, and into what profound caverns it may sink in others? There is something childish in giving us an array of figures, when the figures present no useful approximation to the truth.
We have alluded to the difficult problem of the distribution of the different species of animals throughout the several regions of the globe: the same problem meets us in the vegetable world. Here we might expect to grapple with it with some better hopes of success, yet the difficulties are by no means diminished; we only seem to see them more plainly. In the first place, it is clear, as Mrs Somerville says, that "no similarity of existing circumstances can account for whole families of plants being confined to one particular country, or even to a very limited district, which, as far as we can judge, might have grown equally well in many others." But the difference of the floras is not the only difficulty. While there is difference in a great number of the species, there is identity in a certain other number. If now we account for the difference by supposing that the several portions of land emerged from the ocean at different epochs, and under different conditions, and that, therefore, the generative powers of vegetable life, (in whatever, under the will of Divine Providence, these may be supposed to consist) manifested themselves differently, how shall we next account for this identity? "In islands far from continents, the number of plants is small; but of these a large proportion occur nowhere else. In St Helena, of thirty flower-bearing plants one or two only are native elsewhere." But these one or two become a new perplexity. "In the Falkland Islands there are more than thirty flowering plants identical with those in Great Britain." Very many similar cases might be cited; we quote these only to show the nature of the difficulty with which science has to cope.
And here comes in the following strange and startling fact, to render this subject of vegetable production still more inexplicable: —
"Nothing grows under these great forests, (of South America;) and when accidentally burnt down in the mountainous parts of Patagonia, they never rise again; but the ground they grow on is soon covered with an impenetrable brushwood of other plants. In Chili the violently stinging Loasa appears first in these burnt places, bushes grow afterwards, and then comes a tree-grass, eighteen feet high, of which the Indians make their huts. The new vegetation that follows the burning of primeval forests is quite unaccountable. The ancient and undisturbed forests of Pennsylvania have no undergrowth; and when burnt down they are succeeded by a thick growth of rhododendrons." – (Vol. ii. p. 190.)
But we must bring our rambling excursion through these pleasant volumes to a close; the more especially as we wish once more to take this opportunity, not as critics only, but as readers also, to express our grateful sense of the benefit which Mrs Somerville has conferred upon society by this and her preceding volume, The Connexion of the Physical Sciences. It was once a prevailing habit to speak in a sort of apologetic strain of works of popular science. Such habit, or whatever residue of it remains, may be entirely laid aside. If by popular science is meant the conveyance, in clear intelligible language, as little technical as possible, of the results of scientific inquiry, then are we all of us beholden more or less to popular science. The most scientific of men cannot be equally profound in all branches of inquiry. The field has now become so extensive that he cannot hope to obtain his knowledge in all departments from the first sources. He must trust for much to the authority of others. Every one who is desirous of learning what anatomy and physiology can teach us, cannot attend the dissecting table. How much that we esteem, as amongst the most valuable of our acquisitions, depends on this secondary evidence! How few can follow the calculations of the mathematician, by which he establishes results which are nevertheless familiar to all as household words! And the mathematician himself, great aristocrat as he is in science, must take the chemist on his word for the nice analysis the latter has performed. He cannot leave his papers to follow out experiments, often as difficult and intricate as his own calculations. Indeed the experiments of the man of science have become so refined and elaborate, and deal often with such subtle matter, and this in so minute quantities, that, as it has been said of the astronomer, that it requires a separate education, and takes half a life to learn to observe, so it may be truly said, that to devise and conduct new experiments in philosophy has become an art in itself. We must be content to see a great deal with the eyes of others; to be satisfied with the report of this or that labourer in the wide field of science. We cannot all of us go wandering over moor and mountain to gather and classify herbs and flowers; interested as we all are in geological speculations, we cannot all use the geological hammer, or use it to any purpose; still less can we examine all manner of fishes, or pry with the microscope into every cranny of nature for infusoria.
Mrs Somerville gives us the book! – the neat, compact, valuable volume, which we hold so commodiously in the hand. The book – the book for ever! There are who much applaud the lecture and the lecture-room, with its table full of glittering apparatus, glass and brass, and all the ingenious instruments by which nature, as we say, is put to the torture. Let such as please spend their hot uneasy hour in a crowd. We could never feed in a crowd; we detest benches and sitting in a row. To our notion, more is got, in half the time, from a few pages of the quiet letterpress, quietly perused: the better if accompanied by skilful diagrams, or, as in this case, by admirable maps. As to those experiments, on the witnessing of which so much stress is laid, it is a great fallacy to suppose that they add anything to the certainty of our knowledge. When we see an experiment performed at a distance, in a theatre, we do, in fact, as entirely rely on the word of the lecturer as if we only read of its performance. It is our faith in his character that makes all the difference between his exhibition and that of the dexterous conjurer. To obtain any additional evidence from beholding the experiment, we ought to be at the elbow of the skilful manipulator, and weigh, and test, and scrutinise.
But, indeed, as a matter of evidence, the experiment in a popular lecture-room is never viewed for a moment. It is a mere show. It has degenerated into a mere expedient to attract idlers and keep them awake. The crowd is there, and expect to see something; and it has become the confirmed habit of the whole class of popular lecturers to introduce their experiments, not when they are wanted to elucidate or prove their propositions, but whenever and wherever they can answer the purpose of amusing the audience. If a learned professor is lecturing upon the theory of combustion, he will burn a piece of stick or paper before you, to show that when such things are burnt flame is produced. He would on no account forego that flame. Yes; and the audience look on as if they had never seen a stick or a piece of paper burn before. And when he is so happy as to arrive at the point where a few grains of gunpowder may be ignited, they give him a round of applause! In the hands of many, the lecture itself becomes little more than an occasion for the experiment. The glittering vials, the air-pump, the electrical machine, undoubtedly keep the eyes at least of the audience open; but the expedient, with all due deference be it said, reminds us of the ingenious resource of the veteran exhibitor of Punch, who knows that if his puppets receive knocks enough, and there is sufficient clatter with the sticks, the dramatic dialogue may take its course as it pleases: he is sure of his popularity.
Therefore it is we are for the book; and we hold such presents as Mrs Somerville has bestowed upon the public to be of incalculable value, disseminating more sound information than all the literary and scientific institutions will accomplish in a whole cycle of their existence. We will conclude with one or two practical suggestions, which would add to the utility of the last of her two works —The Physical Geography. Mrs Somerville has thought it well to insert a few notes explanatory of some scientific terms. But these notes are few. If it was well to explain such terms as "Marsupial animals," or "Testacea," a reader might be excused for wishing to know what a "torsion balance" was, or what a "moraine," – terms which fall upon him just as suddenly, and unexplained by any previous matter. Would not a glossary of such terms be advisable? But whatever may be thought of this suggestion, our next remark is indisputable. To such a work as this, an index is extremely useful – is all but essential. There is an index, but it is so defective, so scanty, that it is worth nothing. We cannot say whether this last remark applies equally to The Connexion of the Physical Sciences, not having that work at present under our eye. But we beg to intimate to all authors and authoresses, that whenever a book is of such a nature that it becomes valuable as a work of reference, it should be accompanied by a good index. It is a plodding business, but it must be executed.