During our stay in Illyria, I made an excursion by water with the
Unknown, my preserver, now become my friend, and Eubathes, to Pola, in
Istria. We entered the harbour of Pola in a felucca when the sun was
setting; and I know no scene more splendid than the amphitheatre seen
from the sea in this light. It appears not as a building in ruins, but
like a newly erected work, and the reflection of the colours of its
brilliant marble and beautiful forms seen upon the calm surface of the
waters gave to it a double effect--that of a glorious production of art
and of a magnificent picture. We examined with pleasure the remains of
the arch of Augustus and the temple, very perfect monuments of imperial
grandeur. But the splendid exterior of the amphitheatre was not in
harmony with the bare and naked walls of the interior; there were none of
those durable and grand seats of marble, such as adorn the amphitheatre
of Verona, from which it is probable that the whole of the arena and
conveniences for the spectators had been constructed of wood. Their
total disappearance led us to reflect upon the causes of the destruction
of so many of the works of the older nations. I said, in our
metaphysical abstractions, we refer the changes, the destruction of
material forms, to time, but there must be physical laws in Nature by
which they are produced; and I begged our new friend to give us some
ideas on this subject in his character of chemical philosopher. If human
science, I said, has discovered the principle of the decay of things, it
is possible that human art may supply means of conservation, and bestow
immortality on some of the works which appear destined by their
perfection for future ages.
_The Unknown_.--I shall willingly communicate to you my views of the
operation of time, philosophically considered. A great philosopher has
said, man can in no other way command Nature but in obeying her laws;
and, in these laws, the principle of change is a principle of life;
without decay, there can be no reproduction; and everything belonging to
the earth, whether in its primitive state, or modified by human hands, is
submitted to certain and immutable laws of destruction, as permanent and
universal as those which produce the planetary motions. The property
which, as far as our experience extends, universally belongs to matter,
gravitation, is the first and most general cause of change in our
terrestrial system; and, whilst it preserves the great mass of the globe
in a uniform state, its influence is continually producing alterations
upon the surface. The water, raised in vapour by the solar heat, is
precipitated by the cool air in the atmosphere; it is carried down by
gravitation to the surface, and gains its mechanical force from this law.
Whatever is elevated above the superfices by the powers of vegetation or
animal life, or by the efforts of man, by gravitation constantly tends to
the common centre of attraction; and the great reason of the duration of
the pyramid above all other forms is, that it is most fitted to resist
the force of gravitation. The arch, the pillar, and all perpendicular
constructions, are liable to fall when a degradation from chemical or
mechanical causes takes place in their inferior parts. The forms upon
the surface of the globe are preserved from the influence of gravitation
by the attraction of cohesion, or by chemical attraction; but if their
parts had freedom of motion, they would all be levelled by this power,
gravitation, and the globe would appear as a plane and smooth oblate
spheroid, flattened at the poles. The attraction of cohesion or chemical
attraction, in its most energetic state, is not liable to be destroyed by
gravitation; this power only assists the agencies of other causes of
degradation. Attraction, of whatever kind, tends, as it were, to produce
rest--a sort of eternal sleep in Nature. The great antagonist power is
heat. By the influence of the sun the globe is exposed to great
varieties of temperature; an addition of heat expands bodies, and an
abstraction of heat causes them to contract; by variation of heat,
certain kinds of matter are rendered fluid, or elastic, and changes from
fluids into solids, or from solids or fluids into elastic substances, and
_vice versa_, are produced; and all these phenomena are connected with
alterations tending to the decay or destruction of bodies. It is not
probable that the mere contraction or expansion of a solid, from the
subtraction or addition of heat, tends to loosen its parts; but if water
exists in these parts, then its expansion, either in becoming vapour or
ice, tends not only to diminish their cohesion, but to break them into
fragments. There is, you know, a very remarkable property of water--its
expansion by cooling, and at the time of becoming ice--and this is a
great cause of destruction in the northern climates; for where ice forms
in the crevices or cavities of stones, or when water which has penetrated
into cement freezes, its expansion acts with the force of the lever or
the screw in destroying or separating the parts of bodies. The
mechanical powers of water, as rain, hail, or snow, in descending from
the atmosphere, are not entirely without effect; for in acting upon the
projections of solids, drops of water or particles of snow, and still
more of hail, have a power of abrasion, and a very soft substance, from
its mass assisting gravitation, may break a much harder one. The
glacier, by its motion, grinds into powder the surface of the granite
rock; and the Alpine torrents, that have their origin under glaciers, are
always turbid, from the destruction of the rocks on which the glacier is
formed. The effect of a torrent in deepening its bed will explain the
mechanical agency of fluid-water, though this effect is infinitely
increased, and sometimes almost entirely dependent, upon the solid
matters which are carried down by it. An angular fragment of stone in
the course of ages moved in the cavity of a rock makes a deep round
excavation, and is worn itself into a spherical form. A torrent of rain
flowing down the side of a building carries with it the silicious dust,
or sand, or matter which the wind has deposited there, and acts upon a
scale infinitely more minute, but according to the same law. The
buildings of ancient Rome have not only been liable to the constant
operation of the rain-courses, or minute torrents produced by rains, but
even the Tiber, swollen with floods of the Sabine mountains and the
Apennines, has often entered into the city, and a winter seldom passes
away in which the area of the Pantheon has not been filled with water,
and the reflection of the cupola seen in a smooth lake below. The
monuments of Egypt are perhaps the most ancient and permanent of those
belonging to the earth, and in that country rain is almost unknown. And
all the causes of degradation connected with the agency of water act more
in the temperate climates than in the hot ones, and most of all in those
countries where the inequalities of temperature are greatest. The
mechanical effects of air are principally in the action of winds in
assisting the operation of gravitation, and in abrading by dust, sand,
stones, and atmospheric water. These effects, unless it be in the case
of a building blown down by a tempest, are imperceptible in days, or even
years; yet a gentle current of air carrying the silicious sand of the
desert, or the dust of a road for ages against the face of a structure,
must ultimately tend to injure it, for with infinite or unlimited
duration, an extremely small cause will produce a very great effect. The
mechanical agency of electricity is very limited; the effects of
lightning have, however, been witnessed, even in some of the great
monuments of antiquity, the Colosaeum at Rome, for instance; and only
last year, in a violent thunderstorm, some of the marble, I have been
informed, was struck from the top of one of the arches in this building,
and a perpendicular rent made, of some feet in diameter. But the
chemical effects of electricity, though excessively slow and gradual, yet
are much more efficient in the great work of destruction. It is to the
general chemical doctrines of the changes produced by this powerful agent
that I must now direct your especial attention.
_Eub_.--Would not the consideration of the subject have been more
distinct, and your explanations of the phenomena more simple, had you
commenced by dividing the causes of change into mechanical and chemical;
if you had first considered them separately, and then their joint
effects?
_The Unknown_.--The order I have adopted is not very remote from this.
But I was perhaps wrong in treating first of the agency of gravitation,
which owes almost all its powers to the operation of other causes. In
consequence of your hint, I shall alter my plan a little, and consider
first the chemical agency of water, then that of air, and lastly that of
electricity. In every species of chemical change, temperature is
concerned. But unless the results of volcanoes and earthquakes be
directly referred to this power, it has no chemical effect in relation to
the changes ascribed to time simply considered as heat, but its
operations, which are the most important belonging to the terrestrial
cycle of changes, are blended with, or bring into activity, those of
other agents. One of the most distinct and destructive agencies of water
depends upon its solvent powers, which are usually greatest when its
temperature is highest. Water is capable of dissolving, in larger or
smaller proportions, most compound bodies, and the calcareous and
alkaline elements of stones are particularly liable to this kind of
operation. When water holds in solution carbonic acid, which is always
the case when it is precipitated from the atmosphere, its power of
dissolving carbonate of lime is very much increased, and in the
neighbourhood of great cities, where the atmosphere contains a large
proportion of this principle, the solvent powers of rain upon the marble
exposed to it must be greatest. Whoever examines the marble statues in
the British Museum, which have been removed from the exterior of the
Parthenon, will be convinced that they have suffered from this agency;
and an effect distinct in the pure atmosphere and temperate climate of
Athens, must be upon a higher scale in the vicinity of other great
European cities, where the consumption of fuel produces carbonic acid in
large quantities. Metallic substances, such as iron, copper, bronze,
brass, tin, and lead, whether they exist in stones, or are used for
support or connection in buildings, are liable to be corroded by water
holding in solution the principles of the atmosphere; and the rust and
corrosion, which are made, poetically, qualities of time, depend upon the
oxidating powers of water, which by supplying oxygen in a dissolved or
condensed state enables the metals to form new combinations. All the
vegetable substances, exposed to water and air, are liable to decay, and
even the vapour in the air, attracted by wood, gradually reacts upon its
fibres and assists decomposition, or enables its elements to take new
arrangements. Hence it is that none of the roofs of ancient buildings
more than a thousand years old remain, unless it be such as are
constructed of stone, as those of the Pantheon of Rome and the tomb of
Theodoric at Ravenna, the cupola of which is composed of a single block
of marble. The pictures of the Greek masters, which were painted on the
wood of the abies, or pine of the Mediterranean, likewise, as we are
informed by Pliny, owed their destruction not to a change in the colours,
not to the alteration of the calcareous ground on which they were
painted, but to the decay of the tablets of wood on which the intonaco or
stucco was laid. Amongst the substances employed in building, wood,
iron, tin, and lead, are most liable to decay from the operation of
water, then marble, when exposed to its influence in the fluid form;
brass, copper, granite, sienite, and porphyry are more durable. But in
stones, much depends upon the peculiar nature of their constituent parts;
when the feldspar of the granite rocks contains little alkali or
calcareous earth, it is a very permanent stone; but, when in granite,
porphyry, or sienite, either the feldspar contains much alkaline matter,
or the mica, schorl, or hornblende much protoxide of iron, the action of
water containing oxygen and carbonic acid on the ferruginous elements
tends to produce the disintegration of the stone. The red granite, black
sienite, and red porphyry of Egypt, which are seen at Rome in obelisks,
columns, and sarcophagi, are amongst the most durable compound stones;
but the grey granites of Corsica and Elba are extremely liable to undergo
alteration: the feldspar contains much alkaline matter; and the mica and
schorl, much protoxide of iron. A remarkable instance of the decay of
granite may be seen in the Hanging Tower of Pisa; whilst the marble
pillars in the basement remain scarcely altered, the granite ones have
lost a considerable portion of their surface, which falls off continually
in scales, and exhibits everywhere stains from the formation of peroxide
of iron. The kaolin, or clay, used in most countries for the manufacture
of fine porcelain or china, is generally produced from the feldspar of
decomposing granite, in which the cause of decay is the dissolution and
separation of the alkaline ingredients.
_Eub_.--I have seen serpentines, basalts, and lavas which internally were
dark, and which from their weight, I should suppose, must contain oxide
of iron, superficially brown or red, and decomposing. Undoubtedly this
was from the action of water impregnated with air upon their ferruginous
elements.
_The Unknown_.--You are perfectly right. There are few compound stones,
possessing a considerable specific gravity, which are not liable to
change from this cause; and oxide of iron amongst the metallic substances
anciently known, is the most generally diffused in nature, and most
concerned in the changes which take place on the surface of the globe.
The chemical action of carbonic acid is so much connected with that of
water, that it is scarcely possible to speak of them separately, as must
be evident from what I have before said; but the same action which is
exerted by the acid dissolved in water is likewise exerted by it in its
elastic state, and in this case the facility with which the quantity is
changed makes up for the difference of the degree of condensation. There
is no reason to believe that the azote of the atmosphere has any
considerable action in producing changes of the nature we are studying on
the surface; the aqueous vapour, the oxygen and the carbonic acid gas,
are, however, constantly in combined activity, and above all the oxygen.
And, whilst water, uniting its effects with those of carbonic acid, tends
to disintegrate the parts of stones, the oxygen acts upon vegetable
matter. And this great chemical agent is at once necessary, in all the
processes of life and in all those of decay, in which Nature, as it were,
takes again to herself those instruments, organs, and powers, which had
for a while been borrowed and employed for the purpose or the wants of
the living principle. Almost everything effected by rapid combinations
in combustion may also be effected gradually by the slow absorption of
oxygen; and though the productions of the animal and vegetable kingdom
are much more submitted to the power of atmospheric agents than those of
the mineral kingdom, yet, as in the instances which have just been
mentioned, oxygen gradually destroys the equilibrium of the elements of
stones, and tends to reduce into powder, to render fit for soils, even
the hardest aggregates belonging to our globe. Electricity, as a
chemical agent, may be considered not only as directly producing an
infinite variety of changes, but likewise as influencing almost all which
take place. There are not two substances on the surface of the globe
that are not in different electrical relations to each other; and
chemical attraction itself seems to be a peculiar form of the exhibition
of electrical attraction; and wherever the atmosphere, or water, or any
part of the surface of the earth gains accumulated electricity of a
different kind from the contiguous surfaces, the tendency of this
electricity is to produce new arrangements of the parts of these
surfaces; thus a positively electrified cloud, acting even at a great
distance on a moistened stone, tends to attract its oxygenous, or
acidiform or acid, ingredients, and a negatively electrified cloud has
the same effect upon its earthy, alkaline, or metallic matter. And the
silent and slow operation of electricity is much more important in the
economy of Nature than its grand and impressive operation in lightning
and thunder. The chemical agencies of water and air are assisted by
those of electricity; and their joint effects combined with those of
gravitation and the mechanical ones I first described are sufficient to
account for the results of time. But the physical powers of Nature in
producing decay are assisted likewise by certain agencies or energies of
organised beings. A polished surface of a building or a statue is no
sooner made rough from the causes that have been mentioned than the seeds
of lichens and mosses, which are constantly floating in our atmosphere,
make it a place of repose, grow, and increase, and from their death,
their decay, and decomposition carbonaceous matter is produced, and at
length a soil is formed, in which grass can fix its roots. In the
crevices of walls, where this soil is washed down, even the seeds of
trees grow, and, gradually as a building becomes more ruined, ivy and
other parasitical plants cover it. Even the animal creation lends its
aid in the process of destruction when man no longer labours for the
conservation of his works. The fox burrows amongst ruins, bats and birds
nestle in the cavities in walls, the snake and the lizard likewise make
them their habitation. Insects act upon a smaller scale, but by their
united energies sometimes produce great effect; the ant, by establishing
her colony and forming her magazines, often saps the foundations of the
strongest buildings, and the most insignificant creatures triumph, as it
were, over the grandest works of man. Add to these sure and slow
operations the devastations of war, the effects of the destructive zeal
of bigotry, the predatory fury of barbarians seeking for concealed wealth
under the foundations of buildings, and tearing from them every metallic
substance, and it is rather to be wondered that any of the works of the
great nations of antiquity are still in existence.
_Phil_.--Your view of the causes of devastation really is a melancholy
one. Nor do I see any remedy; the most important causes will always
operate. Yet, supposing the constant existence of a highly civilised
people, the ravages of time might be repaired, and by defending the
finest works of art from the external atmosphere, their changes would be
scarcely perceptible.
_Eub_.--I doubt much whether it is for the interests of a people that its
public works should be of a durable kind. One of the great causes of the
decline of the Roman Empire was that the people of the Republic and of
the first empire left nothing for their posterity to do; aqueducts,
temples, forums, everything was supplied, and there were no objects to
awaken activity, no necessity to stimulate their inventive faculties, and
hardly any wants to call forth their industry.
_The Unknown_.--At least, you must allow the importance of preserving
objects of the fine arts. Almost everything we have worthy of admiration
is owing to what has been preserved from the Greek school, and the
nations who have not possessed these works or models have made little or
no progress towards perfection. Nor does it seem that a mere imitation
of Nature is sufficient to produce the beautiful or perfect; but the
climate, the manners, customs, and dress of the people, its genius and
taste, all co-operate. Such principles of conservation as Philalethes
has referred to are obvious. No works of excellence ought to be exposed
to the atmosphere, and it is a great object to preserve them in
apartments of equable temperature and extremely dry. The roofs of
magnificent buildings should be of materials not likely to be dissolved
by water or changed by air. Many electrical conductors should be placed
so as to prevent the slow or the rapid effects of atmospheric
electricity. In painting, lapis lazuli or coloured hard glasses, in
which the oxides are not liable to change, should be used, and should be
laid on marble or stucco encased in stone, and no animal or vegetable
substances, except pure carbonaceous matter, should be used in the
pigments, and none should be mixed with the varnishes.
_Eub_.--Yet, when all is done that can be done in the work of
conservation, it is only producing a difference in the degree of
duration. And from the statements that our friend has made it is evident
that none of the works of a mortal being can be eternal, as none of the
combinations of a limited intellect can be infinite. The operations of
Nature, when slow, are no less sure; however man may for a time usurp
dominion over her, she is certain of recovering her empire. He converts
her rocks, her stones, her trees, into forms of palaces, houses, and
ships; he employs the metals found in the bosom of the earth as
instruments of power, and the sands and clays which constitute its
surface as ornaments and resources of luxury; he imprisons air by water,
and tortures water by fire to change or modify or destroy the natural
forms of things. But, in some lustrums his works begin to change, and in
a few centuries they decay and are in ruins; and his mighty temples,
framed as it were for immortal and divine purposes, and his bridges
formed of granite and ribbed with iron, and his walls for defence, and
the splendid monuments by which he has endeavoured to give eternity even
to his perishable remains, are gradually destroyed; and these structures,
which have resisted the waves of the ocean, the tempests of the sky, and
the stroke of the lightning, shall yield to the operation of the dews of
heaven, of frost, rain, vapour, and imperceptible atmospheric influences;
and, as the worm devours the lineaments of his mortal beauty, so the
lichens and the moss and the most insignificant plants shall feed upon
his columns and his pyramids, and the most humble and insignificant
insects shall undermine and sap the foundations of his colossal works,
and make their habitations amongst the ruins of his palaces and the
falling seats of his earthly glory.
_Phil_.--Your history of the laws of the inevitable destruction of
material forms recalls to my memory our discussion at Adelsberg. The
changes of the material universe are in harmony with those which belong
to the human body, and which you suppose to be the frame or machinery of
the sentient principle. May we not venture to imagine that the visible
and tangible world, with which we are acquainted by our sensations, bears
the same relation to the Divine and Infinite Intelligence that our organs
bear to our mind, with this only difference, that in the changes of the
divine system there is no decay, there being in the order of things a
perfect unity, and all the powers springing from one will and being a
consequence of that will, are perfectly and unalterably balanced. Newton
seemed to apprehend, that in the laws of the planetary motions there was
a principle which would ultimately be the cause of the destruction of the
system. Laplace, by pursuing and refining the principles of our great
philosopher, has proved that what appeared sources of disorder are, in
fact, the perfecting machinery of the system, and that the principle of
conservation is as eternal as that of motion.
_The Unknown_.--I dare not offer any speculations on this grand and awful
subject. We can hardly comprehend the cause of a simple atmospheric
phenomenon, such as the fall of a heavy body from a meteor; we cannot
even embrace in one view the millionth part of the objects surrounding
us, and yet we have the presumption to reason upon the infinite universe
and the eternal mind by which it was created and is governed. On these
subjects I have no confidence in reason, I trust only to faith; and, as
far as we ought to inquire, we have no other guide but revelation.
_Phil_.--I agree with you that whenever we attempt metaphysical
speculations, we must begin with a foundation of faith. And being sure
from revelation that God is omnipotent and omnipresent, it appears to me
no improper use of our faculties to trace even in the natural universe
the acts of His power and the results of His wisdom, and to draw
parallels from the infinite to the finite mind. Remember, we are taught
that man was created in the image of God, and, I think, it cannot be
doubted that in the progress of society man has been made a great
instrument by his energies and labours for improving the moral universe.
Compare the Greeks and Romans with the Assyrians and Babylonians, and the
ancient Greeks and Romans with the nations of modern Christendom, and it
cannot, I think, be questioned that there has been a great superiority in
the latter nations, and that their improvements have been subservient to
a more exalted state of intellectual and religious existence. If this
little globe has been so modified by its powerful and active inhabitants,
I cannot help thinking that in other systems beings of a superior nature,
under the influence of a divine will, may act nobler parts. We know from
the sacred writings that there are intelligences of a higher nature than
man, and I cannot help sometimes referring to my vision in the Colosaeum,
and in supposing some acts of power of those genii or seraphs similar to
those which I have imagined in the higher planetary systems. There is
much reason to infer from astronomical observations that great changes
take place in the system of the fixed stars: Sir William Herschel,
indeed, seems to have believed that he saw nebulous or luminous matter in
the process of forming suns, and there are some astronomers who believe
that stars have been extinct; but it is more probable that they have
disappeared from peculiar motions. It is, perhaps, rather a poetical
than a philosophical idea, yet I cannot help forming the opinion that
genii or seraphic intelligences may inhabit these systems and may be the
ministers of the eternal mind in producing changes in them similar to
those which have taken place on the earth. Time is almost a human word
and change entirely a human idea; in the system of Nature we should
rather say progress than change. The sun appears to sink in the ocean in
darkness, but it rises in another hemisphere; the ruins of a city fall,
but they are often used to form more magnificent structures as at Rome;
but, even when they are destroyed, so as to produce only dust, Nature
asserts her empire over them, and the vegetable world rises in constant
youth, and--in a period of annual successions, by the labours of man
providing food--vitality, and beauty upon the wrecks of monuments, which
were once raised for purposes of glory, but which are now applied to
objects of utility.