The Epochs of Nature
288
The Epochs of Nature
288Hardcover
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Product Details
| ISBN-13: | 9780226395432 |
|---|---|
| Publisher: | University of Chicago Press |
| Publication date: | 04/05/2018 |
| Pages: | 288 |
| Product dimensions: | 6.00(w) x 9.00(h) x 0.80(d) |
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CHAPTER 1
First Discourse
In civil history, one consults documents, studies old medals, deciphers antique inscriptions, to determine the epochs of human revolution and to establish the dates of moral events. Likewise, in natural history, one must rummage through the Earth's archives, pull ancient monuments from the entrails of the Earth, reassemble their remains, and put together in a body of evidence all of the indications of physical change that can allow us to reach back into the different ages of Nature. This is the only way to fix some points in the immensity of space, to place some milestones along the eternal passage of time. Time is like distance: our view would diminish in it, and also even get lost in it, if our history and chronology did not provide lanterns and torches in the darkest places. But, despite the light shed by the written tradition, if one goes back only a few centuries, then what uncertainties in the facts! — what errors are made regarding the causes of events! — and what profound obscurity surrounds yet older times! Moreover, the written word conveys to us only the actions of a few Nations — that is, the actions of a tiny part of the human race. All of the other peoples have left nothing for us, nothing for posterity. They only emerged from nothingness to pass like shadows, leaving no trace — and praise the heavens that the names of all the supposed Heroes, whose crimes and bloody exploits were once celebrated, have passed into oblivion!
Thus, civil history, limited on one side by the shadows of a time that is quite close enough to ours, extends on the other only to small parts of the world, successively inhabited by peoples mindful of their collective memory. Natural history, by contrast, encompasses equally all of space, all of time, and has no limits other than those of the universe.
Nature, being contemporary with matter, space, and time, its history is that of all substances, of all places, of all ages. It may seem at first sight that its great works neither alter nor change, and that, in its productions — even the most fragile and fleeting — it shows itself as forever the same, since at every moment its first models reappear to our eyes in new representations. However, looking more closely, one can see that its course is not completely uniform: one can see that Nature admits distinct variation, shows successive changes, and is even given to forming new combinations and mutations in composition and in form. Thus, as much as it can seem constant overall, it shows variation in all of its parts. And, if we try to encompass its entire span, we cannot doubt that is very different today than it was at its beginnings, and to what it will become as time passes. These are the various changes that we can call its epochs. Nature is found in different states: the surface of the Earth has taken successively different forms: even the heavens have varied, and all things in the physical universe, like those of the moral world, are in a continual movement of successive changes. For example, the state in which we today see Nature is as much our work as its own: we have learned to temper it, modify it, bend it to our needs and desires. We have penetrated deep into, cultivated, and made fertile the Earth: the face it now shows is therefore quite different from that of times before the invention of arts. The golden age of morality — or rather that of fable — was only the iron age of physics and of truth. The people of those days were still half savage, dispersed, few in number, and did not sense their power or know their real worth; the treasure of their lights was still hidden. Man was unaware of the power of a united will and did not suspect that, through society and through sustained, concerted work, he would come to imprint his ideas on the entire face of the universe.
Therefore, one has to go to seek, and look upon, Nature in newly discovered lands, in countries that have remained uninhabited, to gain an idea of its ancient state. And, that ancient state is still modern in comparison to that state where terrestrial continents were covered by the waters, where fish once lived above our plains, where our mountains formed the reefs of the seas. How many changes and different states must have succeeded each other since those antique times (which were not, though, the first times of all) up until the ages of history! How many things lie buried; how many events have been entirely forgotten; and how many revolutions have taken place beyond the reach of human memory! It took a very long succession of observations, over thirty centuries of the culture of the human mind, just to sketch out the present order of things. The Earth has not yet been entirely explored. It is only recently that its true shape has been determined, and it is only in our days that one has been able to form a theory of its internal structure, to demonstrate the order and arrangement of the materials of which it is composed. Hence it is only now that one can begin to compare Nature with itself, and reach back from its known, present-day state into epochs of a more ancient state.
But it is a case here of penetrating the darkness of time: of surveying, by observation of present-day objects, the former existence of things now destroyed, and to get back, through the sole force of substantive facts, to the historical truth of buried things. It is a matter, in a word, of judging, not just the modern past, but also the much more ancient past, only from what is in the present. For us to reach this viewpoint, we need to combine all our powers, and to make use of three main pathways: (1) those facts that allow us to get near the origin of Nature; (2) the monuments that one can regard as witness to its first ages; (3) the traditions that can give us some idea of subsequent ages. After this, we must try to tie together the whole through use of analogies and to form a chain that, from the summit of the ladder of time, can descend as far as to us.
First Fact The Earth is raised at its equator and depressed at its poles, in the proportions demanded by the laws of gravity and of centrifugal force.
Second Fact The terrestrial globe has its own internal heat, which is independent of that conveyed to it by the rays of the Sun.
Third Fact The heat that the Sun sends to the Earth is relatively small by comparison with the heat within the terrestrial globe; and that the heat from the Sun would not be sufficient by itself to sustain living Nature.
Fourth Fact The materials that make up the globe of the Earth are in general of the nature of glass, and can all be reduced to glass.
Fifth Fact One finds on all of the Earth's surface, and even on mountains up to 1,500 to 2,000 toises in height, an immense quantity of shells and other debris of the sea's production.
Let us look first if, in these facts that I wish to use, there is anything that one can reasonably dispute. Let us see if they can all be proved — or at least if they are capable of being so. After that we will pass on to the deductions that we can draw from them.
The first fact, of the bulging out of the Earth at the equator and its flattening at the poles, is mathematically demonstrated and physically proven by the theory of gravitation and by experiments with a pendulum. The terrestrial globe has precisely the shape that a fluid globe would take that rotates with the speed that we know that the Earth's globe possesses. Therefore the first consequence arising from this incontestable fact is that the matter of which our Earth is made was in a fluid state at the moment when it took its form, and that that was also the moment when it first began to rotate. If the Earth had not been fluid, and had it the same consistency that we see in it today, it is clear that the consistent and solid matter would not have obeyed the law of centrifugal force, and therefore, despite the speed of its rotation, the Earth, rather than being a spheroid bulging out at its equator and being flattened at the poles, would be a perfect sphere and it could not have taken any shape but that of a perfect sphere, by virtue of the mutual attraction of all of the particles of matter of which it is composed.
And, as in general all fluidity has heat as its cause, since water itself without heat would form only a solid substance, we have two different manners of appreciating the possibility of this primitive state of fluidity of the terrestrial globe, because it seems initially that Nature has two means of effecting this. The first is of dissolution or even the suspension of terrestrial materials in water, and the second is liquefaction by fire. But we know that the great majority of the solid materials that make up the terrestrial globe are not soluble in water — and at the same time we can see that the amount of water is so small in comparison to dry matter, that it is not possible that one could ever have been suspended in the other. Thus the fluidity, which once was possessed by the entire mass of the Earth, could not have been caused either by dissolution or by suspension in water. That fluidity must have been a liquefaction caused by fire.
This just consequence, already reasonable in itself, gains a new degree of probability through the second fact, and it becomes a certainty from the third fact. The internal heat of the Earth, that is still present and that is much greater than that which comes to us from the Sun, shows us that this ancient fire, which the Earth experienced, has not yet dissipated entirely. The surface of the Earth is colder than the interior. Certain and repeated observations assure us that the entire mass of the Earth has its own heat that is quite independent of that from the Sun. This heat is manifest to us by comparison of our winters and our summers, and one senses it, in a manner that is yet more palpable, once one penetrates below the surface. It is constant in all places for each depth, and seems to increase the farther one descends. But what are such observations in comparison to those that would be needed to trace the successive degrees of internal heat in the depths of the Earth? We have excavated into the mountains to depths of a few hundred toises to extract metals. On the plains, we have dug wells to a few hundred feet. These are our greatest excavations, or rather our deepest trenches. They barely scratch the surface of the outer rind of the Earth, and nevertheless the internal heat there is already more noticeable than that at the surface. One therefore presumes that if one penetrates farther, the heat would become greater, and that those regions close to the center of the Earth are hotter than those more distant from it — just as one sees a fire-heated cannonball maintain its incandescence internally long after its surface has lost its incandescent state and red glow. The fire — or rather the internal heat — of the Earth is also indicated by the effects of electricity, which converts this invisible heat into luminous thunderbolts. It is shown to us by the temperature of the water in the sea, which at the same depths is about equal to that of the interior of the Earth. Besides, it is easy to show that the liquid state of the water in the oceans in general cannot be attributed to the power of the Sun's rays, because it can be shown by experiment that sunlight does not penetrate more than six hundred feet even through the most limpid of waters, and therefore its heat does not reach even a quarter of this depth, that is to say, to one hundred and fifty feet. Thus, all of the waters that lie below this depth would be frozen, without the internal heat of the Earth that can maintain its liquid state. Similarly, it can be proven by experiment that the heat of the Sun's rays do not penetrate more than fifteen or twenty feet into the Earth, because ice can be kept at such depths even during the hottest summers. Thus it is evident that beneath the ocean basins, just as in the primary layers of the Earth, there is a continual emanation of heat that keeps water liquid and gives rise to the temperature of the Earth. Thus there is a heat in its interior that inherently belongs to it, and is quite independent of that which the Sun can provide.
We can confirm this general fact by a great number of specific facts. Everyone has noticed that, in the times of frost, snow melts in all of those places where vapors from the interior of the Earth have free passage, as above wells, covered aqueducts, vaults, cisterns, and so on, while, over the rest of the area where the ground is gripped by ice and intercepts these vapors, snow remains, and freezes instead of melting. That in itself suffices to show that the emanations from the Earth's interior possess a quantity of heat that is very real and detectable. But it is useless here to wish to gather new proofs of a fact that is clear from experiment and observation. It is sufficient that one cannot henceforth place this into doubt, and that one recognizes the internal heat of the Earth as a real and genuine fact, from which, as from other general facts of Nature, one must deduce particular consequences.
There is from this a fourth fact: one cannot doubt, following demonstrable proofs that we have given in several sections of our Theory of the Earth, that the materials of which the Earth is made are of the nature of glass. The basis of minerals, of plants and animals, is rather made of vitrescible matter, because all of their residues, all of their subsequent waste, can be reduced to glass. The materials that the chemists call refractory and those that they regard as infusible, because they resist the fires of their furnaces, can nevertheless be so reduced by the action of a more intense fire. In this way, all of the materials that compose the globe of the Earth — at least all that are known to us — have glass as the basis of their substance, and we can, on submitting them to the powerful action of fire, subsequently reduce them all to their primary state.
The primitive liquefaction of the entire mass of the Earth by fire is therefore proved with all the rigor demanded by the strictest logic. First, a priori, by the first fact of the Earth's own elevation at its equator, and its depression at the poles. Second, ab actu, by the second and third facts concerning the Earth's still-persistent internal heat. Third, a posteriori, by the fourth fact, which shows us the product of this action of fire, that is to say, glass, in all terrestrial substances.
But although the materials that make up the globe of the Earth were primordially of the nature of glass, and one can reduce them to this subsequently, one must nevertheless distinguish and separate them, relative to the different states in which they are found before they return to their primary state, that is to say, before they revert to glass through the action of fire. This consideration is all the more necessary here, because only that can show us how the formation of these materials differs. One thus first has to divide them into vitrescible materials and calcinable materials. The first of these do not show any effect from fire unless they are subjected to a sufficient degree of its force to convert them into glass. The others, by contrast, undergo, at much lesser levels, a process that converts them into lime. The quantity of calcareous substances, although considerable on Earth, is nevertheless very small by comparison with the quantity of the vitrescible materials.
The fifth fact we have put forward proves that their formation also came at a different time and from a different element. And one sees clearly that all materials that were not formed directly by the action of primitive fire were formed via the intermediary of water — because all are made of shells and other debris that are the products of the sea. We place in the class of vitrescible materials quartz, crystalline rock, sands, sandstones, and granites; also slates, shales, clays, metals, and metallic minerals. These materials taken together form the true foundations of the globe and make up the principal and by far the greater part of it.
All were originally produced by primitive fire. Sand is only powdered glass, and clays are sands that have decayed in water. Slates and shales are dried and hardened clays. Quartz, crystalline rock, sandstones, and granite are only vitreous masses or vitrescible sands in concrete form; pebbles, crystals, metals, and most other minerals are only distillates, exudations, or sublimates of primary materials, which all reveal to us their primitive origin and common nature, by their aptitude to be reduced directly into glass.
(Continues…)
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Table of Contents
Preface Translators’ Note Introduction: Buffon and the History of the EarthJan Zalasiewicz, Sverker Sörlin, Libby Robin, and Jacques GrinevaldThe Epochs of Nature First Discourse First Epoch When the Earth and the Planets Took Their Form Second Epoch When Matter, Being Consolidated, Formed the Interior Rock of the Globe and the Great Vitrescible Masses That Are at Its Surface Third Epoch When the Waters Covered Our Continents Fourth Epoch When the Waters Retreated and the Volcanoes Became Active Fifth Epoch When the Elephants and the Other Animals of the South Lived in the North Sixth Epoch When the Separation of Continents Was Made Seventh and Last Epoch When the Power of Man Has Assisted That of Nature Justifying Notes to the Facts Reported in the Epochs of Nature
Notes on the First Discourse Notes on the First Epoch Notes on the Second Epoch Notes on the Third Epoch Notes on the Fifth Epoch Notes on the Sixth Epoch Notes on the Seventh Epoch Index