Books: The Harvard Classics Volume 38
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Various >> The Harvard Classics Volume 38
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When some fanciful speculations of this kind had amused their
imaginations for a time, some vast repository of mummies would be
discovered, and would immediately undeceive those antiquaries who
enjoyed an opportunity of personally examining them; but the
prejudices of others at a distance, who were not eye-witnesses of
the whole phenomena, would not be so easily overcome. The
concurrent report of many travellers would, indeed, render it
necessary for them to accommodate ancient theories to some of the
new facts, and much wit and ingenuity would be required to modify
and defend their old positions. Each new invention would violate
a greater number of known analogies; for if a theory be required
to embrace some false principle, it becomes more visionary in
proportion as facts are multiplied, as would be the case if
geometers were now required to form an astronomical system on the
assumption of the immobility of the earth.
Amongst other fanciful conjectures concerning the history of
Egypt, we may suppose some of the following to be started. 'As
the banks of the Nile have been so recently colonized for the
first time, the curious substances called mummies could never in
reality have belonged to men. They may have been generated by
some PLASTIC VIRTUE residing in the interior of the earth, or
they may be abortions of Nature produced by her incipient efforts
in the work of creation. For if deformed beings are sometimes
born even now, when the scheme of the universe is fully
developed, many more may have been "sent before their time scarce
half made up," when the planet itself was in the embryo state.
But if these notions appear to derogate from the perfection of
the Divine attributes, and if these mummies be in all their parts
true representations of the human form, may we not refer them to
the future rather than the past? May we not be looking into the
womb of Nature, and not her grave? May not these images be like
the shades of the unborn in Virgil's Elysium--the archetypes of
men not yet called into existence?'
These speculations, if advocated by eloquent writers, would not
fail to attract many zealous votaries, for they would relieve men
from the painful necessity of renouncing preconceived opinions.
Incredible as such scepticism may appear, it has been rivalled by
many systems of the sixteenth and seventeenth centuries, and
among others by that of the learned Falloppio, who, as we have
seen (p. 33), regarded the tusks of fossil elephants as earthly
concretions, and the pottery or fragments of vases in the Monte
Testaceo, near Rome, as works of nature, and not of art. But when
one generation had passed away, and another, not compromised to
the support of antiquated dogmas, had succeeded, they would
review the evidence afforded by mummies more impartially, and
would no longer controvert the preliminary question, that human
beings had lived in Egypt before the nineteenth century: so that
when a hundred years perhaps had been lost, the industry and
talents of the philosopher would be at last directed to the
elucidation of points of real historical importance.
But the above arguments are aimed against one only of many
prejudices with which the earlier geologists had to contend. Even
when they conceded that the earth had been peopled with animate
beings at an earlier period than was at first supposed, they had
no conception that the quantity of time bore so great a
proportion to the historical era as is now generally conceded.
How fatal every error as to the quantity of time must prove to
the introduction of rational views concerning the state of things
in former ages, may be conceived by supposing the annals of the
civil and military transactions of a great nation to be perused
under the impression that they occurred in a period of one
hundred instead of two thousand years. Such a portion of history
would immediately assume the air of a romance; the events would
seem devoid of credibility, and inconsistent with the present
course of human affairs. A crowd of incidents would follow each
other in thick succession. Armies and fleets would appear to be
assembled only to be destroyed, and cities built merely to fall
in ruins. There would be the most violent transitions from
foreign or intestine war to periods of profound peace, and the
works effected during the years of disorder or tranquillity would
appear alike superhuman in magnitude.
He who should study the monuments of the natural world under the
influence of a similar infatuation, must draw a no less
exaggerated picture of the energy and violence of causes, and
must experience the same insurmountable difficulty in reconciling
the former and present state of nature, If we could behold in one
view all the volcanic cones thrown up in Iceland, Italy, Sicily,
and other parts of Europe, during the last five thousand years,
and could see the lavas which have flowed during the same period;
the dislocations, subsidences, and elevations caused during
earthquakes; the lands added to various deltas, or devoured by
the sea, together with the effects of devastation by floods, and
imagine that all these events had happened in one year, we must
form most exalted ideas of the activity of the agents, and the
suddenness of the revolutions. If geologists, therefore, have
misinterpreted the signs of a succession of events, so as to
conclude that centuries were implied where the characters
indicated thousands of years, and thousands of years where the
language of Nature signified millions, they could not, if they
reasoned logically from such false premises, come to any other
conclusion than that the system of the natural world had
undergone a complete revolution.
We should be warranted in ascribing the erection of the great
pyramid to superhuman power, if we were convinced that it was
raised in one day; and if we imagine, in the same manner, a
continent or mountain-chain to have been elevated during an
equally small fraction of the time which was really occupied in
upheaving it, we might then be justified in inferring, that the
subterranean movements were once far more energetic than in our
own times. We know that; during one earthquake the coast of Chili
may be raised for a hundred miles to the average height of about
three feet. A repetition of two thousand shocks, of equal
violence, might produce a mountain-chain one hundred miles long,
and six thousand feet high. Now, should one or two only of these
convulsions happen in a century, it would be consistent with the
order of events experienced by the Chilians from the earliest
times: but if the whole of them were to occur in the next hundred
years, the entire district must be depopulated, scarcely any
animals or plants could survive, and the surface would be one
confused heap of ruin and desolation.
One consequence of undervaluing greatly the quantity of past
time, is the apparent coincidence which it occasions of events
necessarily disconnected, or which are so unusual, that it would
be inconsistent with all calculation of chances to suppose them
to happen at one and the same time. When the unlooked-for
association of such rare phenomena is witnessed in the present
course of nature, it scarcely ever fails to excite a suspicion of
the preternatural in those minds which are not firmly convinced
of the uniform agency of secondary causes;--as if the death of
some individual in whose fate they are interested happens to be
accompanied by the appearance of a luminous meteor, or a comet,
or the shock of an earthquake. It would be only necessary to
multiply such coincidences indefinitely, and the mind of every
philosopher would be disturbed. Now it would be difficult to
exaggerate the number of physical events, many of them most rare
and unconnected in their nature, which were imagined by the
Woodwardian hypothesis to have happened in the course of a few
months: and numerous other examples might be found of popular
geological theories, which require us to imagine that a long
succession of events happened in a brief and almost momentary
period.
Another liability to error, very nearly allied to the former,
arises from the frequent contact of geological monuments
referring to very distant periods of time. We often behold, at
one glance, the effects of causes which have acted at times
incalculably remote, and yet there may be no striking
circumstances to mark the occurrence of a great chasm in the
chronological series of Nature's archives. In the vast interval
of time which may really have elapsed between the results of
operations thus compared, the physical condition of the earth
may, by slow and insensible modifications, have become entirely
altered; one or more races of organic beings may have passed
away, and yet have left behind, in the particular region under
contemplation, no trace of their existence.
To a mind unconscious of these intermediate events, the passage
from one state of things to another must appear so violent, that
the idea of revolutions in the system inevitably suggests itself.
The imagination is as much perplexed by the deception, as it
might be if two distant points in space were suddenly brought
into immediate proximity. Let us suppose, for a moment, that a
philosopher should lie down to sleep in some arctic wilderness,
and then be transferred by a power, such as we read of in tales
of enchantment, to a valley in a tropical country, where, on
awaking, he might find himself surrounded by birds of brilliant
plumage, and all the luxuriance of animal and vegetable forms of
which Nature is so prodigal in those regions. The most reasonable
supposition, perhaps, which he could make, if by the
necromancer's art he were placed in such a situation, would be,
that he was dreaming; and if a geologist form theories under a
similar delusion, we cannot expect him to preserve more
consistency in his speculations, than in the train of ideas in an
ordinary dream.
It may afford, perhaps, a more lively illustration of the
principle here insisted upon, if I recall to the reader's
recollection the legend of the Seven Sleepers. The scene of that
popular fable was placed in the two centuries which elapsed
between the reign of the emperor Decius and the death of
Theodosius the younger. In that interval of time (between the
years 249 and 450 of our era) the union of the Roman empire had
been dissolved, and some of its fairest provinces overrun by the
barbarians of the north. The seat of government had passed from
Rome to Constantinople, and the throne from a pagan persecutor to
a succession of Christian and orthodox princes. The genius of the
empire had been humbled in the dust, and the altars of Diana and
Hercules were on the point of being transferred to Catholic
saints and martyrs. The legend relates, 'that when Decius was
still persecuting the Christians, seven noble youths of Ephesus
concealed themselves in a spacious cavern in the side of an
adjacent mountain, where they were doomed to perish by the
tyrant, who gave orders that the entrance should be firmly
secured with a pile of huge stones. They immediately fell into a
deep slumber, which was miraculously prolonged, without injuring
the powers of life, during a period of 187 years. At the end of
that time the slaves of Adolius, to whom the inheritance of the
mountain had descended, removed the stones to supply materials
for some rustic edifice: the light of the sun darted into the
cavern, and the seven sleepers were permitted to awake. After a
slumber, as they thought, of a few hours, they were pressed by
the calls of hunger, and resolved that Jamhlichus, one of their
number, should secretly return to the city to purchase bread for
the use of his companions. The youth could no longer recognise
the once familiar aspect of his native country, and his surprise
was increased by the appearance of a large cross triumphantly
erected over the principal gate of Ephesus. His singular dress
and obsolete language confounded the baker, to whom he offered an
ancient medal of Decius as the current coin of the empire; and
Jamblichus, on the suspicion of a secret treasure, was dragged
before the judge. Their mutual enquiries produced the amazing
discovery, that two centuries were almost elapsed since
Jamblichus and his friends had escaped from the rage of a pagan
tyrant.'
This legend was received as authentic throughout the Christian
world before the end of the sixth century, and was afterwards
introduced by Mahomet as a divine revelation into the Koran, and
from hence was adopted and adorned by all the nations from Bengal
to Africa who professed the Mahometan faith. Some vestiges even
of a similar tradition have been discovered in Scandinavia. 'This
easy and universal belief,' observes the philosophical historian
of the Decline and Fall, 'so expressive of the sense of mankind,
may be ascribed to the genuine merit of the fable itself. We
imperceptibly advance from youth to age, without observing the
gradual, but incessant, change of human affairs; and even, in our
larger experience of history, the imagination is accustomed, by a
perpetual series of causes and effects, to unite the most distant
revolutions. But if the interval between two memorable eras could
be instantly annihilated; if it were possible, after a momentary
slumber of two hundred years, to display the new world to the
eyes of a spectator who still retained a lively and recent
impression of the old, his surprise and his reflections would
furnish the pleasing subject of a philosophical romance.'
[Footnote: Gibbon, Decline and Fall. chap, xxxiii.]
PREJUDICES ARISING FROM OUR PECULIAR POSITION AS INHABITANTS OF
THE LAND.--The sources of prejudice hitherto considered may be
deemed peculiar for the most part to the infancy of the science,
but others are common to the first cultivators of geology and to
ourselves, and are all singularly calculated to produce the same
deception, and to strengthen our belief that the course of Nature
in the earlier ages differed widely from that now established.
Although these circumstances cannot be fully explained without
assuming some things as proved, which it has been my object
elsewhere to demonstrate, [Footnote: Elements of Geology, 6th
edit., 1865; and Student's Elements, 1871.] it may be well to
allude to them briefly in this place.
The first and greatest difficulty, then, consists in an habitual
unconsciousness that our position as observers is essentially
unfavourable, when we endeavour to estimate the nature and
magnitude of the changes now in progress. In consequence of our
inattention to this subject, we are liable to serious mistakes in
contrasting the present with former states of the globe. As
dwellers on the land, we inhabit about a fourth part of the
surface; and that portion is almost exclusively a theatre of
decay, and not of reproduction. We know, indeed, that new
deposits are annually formed in seas and lakes, and that every
year some new igneous rocks are produced in the bowels of the
earth, but we cannot watch the progress of their formation, and
as they are only present to our minds by the aid of reflection,
it requires an effort both of the reason and the imagination to
appreciate duly their importance. It is, therefore, not
surprising that we estimate very imperfectly the result of
operations thus unseen by us; and that, when analogous results of
former epochs are presented to our inspection, we cannot
immediately recognise the analogy. He who has observed the
quarrying of stone from a rock, and has seen it shipped for some
distant port, and then endeavours to conceive what kind of
edifice will be raised by the materials, is in the same
predicament as a geologist, who, while he is confined to the
land, sees the decomposition of rocks, and the transportation of
matter by rivers to the sea, and then endeavours to picture to
himself the new strata which Nature is building beneath the
waters.
PREJUDICES ARISING FROM OUR NOT SEEING SUBTERRANEAN CHANGES.--Nor
is his position less unfavourable when, beholding a volcanic
eruption, he tries to conceive what changes the column of lava
has produced, in its passage upwards, on the intersected strata;
or what form the melted matter may assume at great depths on
cooling; or what may be the extent of the subterranean rivers and
reservoirs of liquid matter far beneath the surface. It should,
therefore, be remembered, that the task imposed on those who
study the earth's history requires no ordinary share of
discretion; for we are precluded from collating the corresponding
parts of the system of things as it exists now, and as it existed
at former periods. If we were inhabitants of another element--if
the great ocean were our domain, instead of the narrow limits of
the land, our difficulties would be considerably lessened; while,
on the other hand, there can be little doubt, although the reader
may, perhaps, smile at the bare suggestion of such an idea, that
an amphibious being, who should possess our faculties, would
still more easily arrive at sound theoretical opinions in
geology, since he might behold, on the one hand, the
decomposition of rocks in the atmosphere, or the transportation
of matter by running water; and, on the other, examine the
deposition of sediment in the sea, and the imbedding of animal
and vegetable remains in new strata. He might ascertain, by
direct observation, the action of a mountain torrent, as well as
of a marine current; might compare the products of volcanos
poured out upon the land with those ejected beneath the waters;
and might mark, on the one hand, the growth of the forest, and,
on the other, that of the coral reef. Yet, even with these
advantages, he would be liable to fall into the greatest errors,
when endeavouring to reason on rocks of subterranean origin. He
would seek in vain, within the sphere of his observation, for any
direct analogy to the process of their formation, and would
therefore be in danger of attributing them, wherever they are
upraised to view, to some 'primeval state of nature.'
But if we may be allowed so far to indulge the imagination, as to
suppose a being entirely confined to the nether world--some
'dusky melancholy sprite,' like Umbriel, who could 'flit on sooty
pinions to the central earth,' but who was never permitted to
'sully the fair face of light,' and emerge into the regions of
water and of air; and if this being should busy himself in
investigating the structure of the globe, he might frame theories
the exact converse of those usually adopted by human
philosophers. He might infer that the stratified rocks,
containing shells and other organic remains, were the oldest of
created things, belonging to some original and nascent state of
the planet. 'Of these masses' he might say, 'whether they consist
of loose incoherent sand, soft clay, or solid stone, none have
been formed in modern times. Every year some of them are broken
and shattered by earthquakes, or melted by volcanic fire; and
when they cool down slowly from a state of fusion, they assume a
new and more crystalline form, no longer exhibiting that
stratified disposition and those curious impressions and
fantastic markings, by which they were previously characterised.
This process cannot have been carried on for an indefinite time,
for in that case all the stratified rocks would long ere this
have been fused and crystallised. It is therefore probable that
the whole planet once consisted of these mysterious and curiously
bedded formations at a time when the volcanic fire had not yet
been brought into activity. Since that period there seems to have
been a gradual development of heat; and this augmentation we may
expect to continue till the whole globe shall be in a state of
fluidity, or shall consist, in those parts which are not melted,
of volcanic and crystalline rocks.'
Such might be the system of the Gnome at the very time that the
followers of Leibnitz, reasoning on what they saw on the outer
surface, might be teaching the opposite doctrine of gradual
refrigeration, and averring that the earth had begun its career
as a fiery comet, and might be destined hereafter to become a
frozen mass. The tenets of the schools of the nether and of the
upper world would be directly opposed to each other, for both
would partake of the prejudices inevitably resulting from the
continual contemplation of one class of phenomena to the
exclusion of another. Man observes the annual decomposition of
crystalline and igneous rocks, and may sometimes see their
conversion into stratified deposits; but he cannot witness the
reconversion of the sedimentary into the crystalline by
subterranean heat. He is in the habit of regarding all the
sedimentary rocks as more recent than the unstratified, for the
same reason that we may suppose him to fall into the opposite
error if he saw the origin of the igneous class only.
For more than two centuries the shelly strata of the Subapennine
hills afforded matter of speculation to the early geologists of
Italy, and few of them had any suspicion that similar deposits
were then forming in the neighbouring sea. Some imagined that the
strata, so rich in organic remains, instead of being due to
secondary agents, had been so created in the beginning of things
by the fiat of the Almighty. Others, as we have seen, ascribed
the imbedded fossil bodies to some plastic power which resided in
the earth in the early ages of the world. In what manner were
these dogmas at length exploded? The fossil relics were carefully
compared with their living analogues, and all doubts as to their
organic origin were eventually dispelled. So, also, in regard to
the nature of the containing beds of mud, sand, and limestone:
those parts of the bottom of the sea were examined where shells
are now becoming annually entombed in new deposits, Donati
explored the bed of the Adriatic, and found the closest
resemblance between the strata there forming, and those which
constituted hills above a thousand feet high in various parts of
the Italian peninsula. He ascertained by dredging that living
testacea were there grouped together in precisely the same manner
as were their fossil analogues in the inland strata; and while
some of the recent shells of the Adriatic were becoming incrusted
with calcareous rock, be observed that others had been newly
buried in sand and clay, precisely as fossil shells occur in the
Subapennine hills.
In like manner, the volcanic rocks of the Vicentin had been
studied in the beginning of the last century; but no geologist
suspected, before the time of Arduino, that these were composed
of ancient submarine lavas. During many years of controversy, the
popular opinion inclined to a belief that basalt and rocks of the
same class had been precipitated from a chaotic fluid, or an
ocean which rose at successive periods over the continents,
charged with the component elements of the rocks in question. Few
will now dispute that it would have been difficult to invent a
theory more distant from the truth; yet we must cease to wonder
that it gained so many proselytes, when we remember that its
claims to probability arose partly from the very circumstance of
its confirming the assumed want of analogy between geological
causes and those now in action. By what train of investigations
were geologists induced at length to reject these views, and to
assent to the igneous origin of the trappean formations? By an
examination of volcanos now active, and by comparing their
structure and the composition of their lavas with the ancient
trap rocks.
The establishment, from time to time, of numerous points of
identification, drew at length from geologists a reluctant
admission, that there was more correspondence between the
condition of the globe at remote eras and now, and more
uniformity in the laws which have regulated the changes of its
surface, than they at first imagined. If, in this state of the
science, they still despaired of reconciling every class of
geological phenomena to the operations of ordinary causes, even
by straining analogy to the utmost limits of credibility, we
might have expected, at least, that the balance of probability
would now have been presumed to incline towards the close analogy
of the ancient and modern causes. But, after repeated experience
of the failure of attempts to speculate on geological monuments,
as belonging to a distinct order of things, new sects continued
to persevere in the principles adopted by their predecessors.
They still began, as each new problem presented itself, whether
relating to the animate or inanimate world, to assume an original
and dissimilar order of nature; and when at length they
approximated, or entirely came round to an opposite opinion, it
was always with the feeling, that they were conceding what they
had been justified a priori in deeming improbable. In a word, the
same men who, as natural philosophers, would have been most
incredulous respecting any extraordinary deviations from the
known course of nature, if reported to have happened IN THEIR OWN
TIME, were equally disposed, as geologists, to expect the proofs
of such deviations at every period of the past. * * * *
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