I suppose that my readers must be generally aware that glaciers are masses of ice in slow motion, at the rate of from ten to twenty inches a day, and that the stones which are caught between them and the rocks over which they pass, or which are embedded in the ice and dragged along by it over those rocks, are of course subjected to a crushing and grinding power altogether unparalleled by any other force in constant action. The dust to which these stones are reduced by the friction is carried down by the streams which flow from the melting glacier, so that the water which in the morning may be pure, owing what little strength it has chiefly to the rock springs, is in the afternoon not only increased in volume, but whitened with dissolved dust of granite, in proportion to the heat of the preceding hours of the day, and to the power and size of the glacier which feeds it.
§ 2. The long drought which took place in the autumn of the year 1854, sealing every source of waters except these perpetual ones, left the torrent of which I am speaking, and such others, in a state peculiarly favorable to observance of their least action on the mountains from which they descend. They were entirely limited to their own ice fountains, and the quantity of powdered rock which they brought down was, of course, at its minimum, being nearly unmingled with any earth derived from the dissolution of softer soil, or vegetable mould, by rains.
At three in the afternoon, on a warm day in September, when the torrent had reached its average maximum strength for the day, I filled an ordinary Bordeaux wine-flask with the water where it was least turbid. From this quart of water I obtained twenty-four grains of sand and sediment, more or less fine. I cannot estimate the quantity of water in the stream; but the runlet of it at which I filled the flask was giving about two hundred bottles a minute, or rather more, carrying down therefore about three quarters of a pound of powdered granite every minute. This would be forty-five pounds an hour; but allowing for the inferior power of the stream in the cooler periods of the day, and taking into consideration, on the other side, its increased power in rain, we may, I think, estimate its average hour's work at twenty-eight or thirty pounds, or a hundred weight every four hours. By this insignificant runlet, therefore, some four inches wide and four inches deep, rather more than two tons of the substance of the Mont Blanc are displaced, and carried down a certain distance every week; and as it is only for three or four months that the flow of the stream is checked by frost, we may certainly allow eighty tons for the mass which it annually moves.
§ 3. It is not worth while to enter into any calculation of the relation borne by this runlet to the great torrents which descend from the chain of Mont Blanc into the valley of Chamouni. To call it the thousandth part of the glacier waters, would give a ludicrous under-estimate of their total power; but even so calling it, we should find for result that eighty thousand tons of mountain must be yearly transformed into drifted sand, and carried down a certain distance.[49] How much greater than this is the actual quantity so transformed I cannot tell; but take this quantity as certain, and consider that this represents merely the results of the labor of the constant summer streams, utterly irrespective of all sudden falls of stones and of masses of mountain (a single thunderbolt will sometimes leave a scar on the flank of a soft rock, looking like a trench for a railroad); and we shall then begin to apprehend something of the operation of the great laws of change, which are the conditions of all material existence, however apparently enduring. The hills, which, as compared with living beings, seem "everlasting," are, in truth, as perishing as they: its veins of flowing fountain weary the mountain heart, as the crimson pulse does ours; the natural force of the iron crag is abated in its appointed time, like the strength of the sinews in a human old age; and it is but the lapse of the longer years of decay which, in the sight of its Creator, distinguishes the mountain range from the moth and the worm.
§ 4. And hence two questions arise of the deepest interest. From what first created forms were the mountains brought into their present condition? into what forms will they change in the course of ages? Was the world anciently in a more or less perfect state than it is now? was it less or more fitted for the habitation of the human race? and are the changes which it is now undergoing favorable to that race or not? The present conformation of the earth appears dictated, as has been shown in the preceding chapters, by supreme wisdom and kindness. And yet its former state must have been different from what it is now; as its present one from that which it must assume hereafter. Is this, therefore, the earth's prime into which we are born; or is it, with all its beauty, only the wreck of Paradise?
I cannot entangle the reader in the intricacy of the inquiries necessary for anything like a satisfactory solution of these questions. But, were he to engage in such inquiries, their result would be his strong conviction of the earth's having been brought from a state in which it was utterly uninhabitable into one fitted for man;—of its having been, when first inhabitable, more beautiful than it is now; and of its gradually tending to still greater inferiority of aspect, and unfitness for abode.
It has, indeed, been the endeavor of some geologists to prove that destruction and renovation are continually proceeding simultaneously in mountains as well as in organic creatures; that while existing eminences are being slowly lowered, others, in order to supply their place, are being slowly elevated; and that what is lost in beauty or healthiness in one spot is gained in another. But I cannot assent to such a conclusion. Evidence altogether incontrovertible points to a state of the earth in which it could be tenanted only by lower animals, fitted for the circumstances under which they lived by peculiar organizations. From this state it is admitted gradually to have been brought into that in which we now see it; and the circumstances of the existing dispensation, whatever may be the date of its endurance, seem to me to point not less clearly to an end than to an origin; to a creation, when "the earth was without form and void," and to a close, when it must either be renovated or destroyed.
§ 5. In one sense, and in one only, the idea of a continuous order of things is admissible, in so far as the phenomena which introduced, and those which are to terminate, the existing dispensation, may have been, and may in future be, nothing more than a gigantic development of agencies which are in continual operation around us. The experience we possess of volcanic agency is not yet large enough to enable us to set limits to its force; and as we see the rarity of subterraneous action generally proportioned to its violence, there may be appointed, in the natural order of things, convulsions to take place after certain epochs, on a scale which the human race has not yet lived long enough to witness. The soft silver cloud which writhes innocently on the crest of Vesuvius, rests there without intermission; but the fury which lays cities in sepulchres of lava bursts forth only after intervals of centuries; and the still fiercer indignation of the greater volcanoes, which make half the globe vibrate with earthquake, and shrivels up whole kingdoms with flame, is recorded only in dim distances of history: so that it is not irrational to admit that there may yet be powers dormant, not destroyed, beneath the apparently calm surface of the earth, whose date of rest is the endurance of the human race, and whose date of action must be that of its doom. But whether such colossal agencies are indeed in the existing order of things or not, still the effective truth, for us, is one and the same. The earth, as a tormented and trembling ball, may have rolled in space for myriads of ages before humanity was formed from its dust; and as a devastated ruin it may continue to roll, when all that dust shall again have been mingled with ashes that never were warmed by life, or polluted by sin. But for us the intelligible and substantial fact is that the earth has been brought, by forces we know not of, into a form fitted for our habitation: on that form a gradual, but destructive, change is continually taking place, and the course of that change points clearly to a period when it will no more be fitted for the dwelling-place of men.
§ 6. It is, therefore, not so much what these forms of the earth actually are, as what they are continually becoming, that we have to observe; nor is it possible thus to observe them without an instinctive reference to the first state out of which they have been brought. The existing torrent has dug its bed a thousand feet deep. But in what form was the mountain originally raised which gave that torrent its track and power? The existing precipice is wrought into towers and bastions by the perpetual fall of its fragments. In what form did it stand before a single fragment fell?
Yet to such questions, continually suggesting themselves, it is never possible to give a complete answer. For a certain distance, the past work of existing forces can be traced; but there gradually the mist gathers, and the footsteps of more gigantic agencies are traceable in the darkness; and still, as we endeavor to penetrate farther and farther into departed time, the thunder of the Almighty power sounds louder and louder; and the clouds gather broader and more fearfully, until at last the Sinai of the world is seen altogether upon a smoke, and the fence of its foot is reached, which none can break through.