Physical geography , is the rational description of the main phenomena of the earth, and the consideration of the general results inferred from local and particular observations, combined and united methodically in different classes, and within a framework capable of making known the natural economy of the globe, insofar as it is considered simply as a mass irrespective of its habitability by living things. [1]

In proportion as Geography and Physics [2] are improved, the luminous principles of the latter and the dry and spare details of the former have been drawn together. As a result of this fortunate association, our own abode, our habitation which had presented us with a picture of no more than a heap of debris and a world in ruins, with irregularities at its surface, with apparent disorders in its interior, [3] has now appeared to our enlightened eyes with external signs where order and uniformity have stood out, where general relationships have been disclosed beneath our feet. [4] No longer were we occupied only with the tedious nomenclature of strange words, which attest the extremities that conquerors’ ambition has placed on the settlements that different societies have formed over the earth’s surface; lands and countries were now distinguished only by the phenomena they offer for our observation. As regards both singular and generalized phenomena, everything bearing the marks of nature’s work was gathered with care and was thought through with exactitude. The form, disposition, and relations of different objects were examined; attempts were even made to judge the extent of the effects, to fix their limits, while supplementing observation with experiment. [5] Finally, there was curiosity to arrive at general principles, constant and regular. In the course of the development of ideas, the creative geographer took as the base of his topographic descriptions the history of the globe’s surface, [6] and allocated by land and country that which the naturalist described and categorized by classes and by sequence of collection.

Such is the summary of progress in Physical geography ; it is owed to the combined assistance which several fields of knowledge have cooperatively supplied. In fact it is not possible to gather together too many resources, when debate embraces matters so vast and extensive; when it is proposed to examine the exterior and interior constitution of the earth, to grasp the general results of observations that have been made and collected on the land’s heights and depths and the inequalities of the sea basin, on the motions and fluctuations of the immense mass of water covering the greater part of the globe’s surface, on the terrestrial substances that compose the primary continental beds [7] that have been so far subjected to scrutiny, on their disposition in layers, on the direction of mountains, etc., and in short on the globe’s organization: when one aspires to knowledge of the main operations of nature, when one debates their influence on particular and subordinate phenomena, and when by a connected chain of facts and reasoning one forms a scheme of explanation, there one limits oneself wisely to establishing analogies and principles.

In accord with these considerations which give us an idea of the subject of Physical geography , in this article we think we should apply ourselves to two important points: 1. To develop the principles of this science capable of guiding observers concerned to extend further its boundaries, and those who wish to appraise their discoveries. 2. To present succinctly the general and confirmed results forming the body of this science, so as to ascertain its present state.

I. The principles of Physical geography can be reduced to three general classes. The first includes those concerned with the observation of facts; the second, those aimed at their combination; finally, the third, those related to the generalization of results and to the establishment of those fertile principles which in the hands of an observer become instruments that he applies advantageously to the discovery of new facts.

Principles concerning the observation of facts . [8] It is not as important to show the necessity of observation to increase our real knowledge in Physical geography , as it is to develop the practice and proper method of observing. There is general agreement now about the harm brought on by the idle presumption that inclines people to try to understand nature without consulting it. Sagacity and meditation cannot take the place of solid and luminous answers provided by nature when we interrogate it; on the contrary, these faculties take such answers to be the primary stuff toward which their main effort is directed. We must never let these principles pass unnoticed. Heraclitus complained that the philosophers of his time sought knowledge in little worlds built by their imagination, and not in the real world. Were we to lay ourselves open to deserving the same reproach, were we to lose sight of such wise advice, we would misjudge our own interests as much as the interests of truth. What remains of these fine musings of the ancients? Only the true and reliable defies the ravages of time and the darkness of oblivion. Can general abstractions about nature begin to compare in utility with a single phenomenon well perceived and well examined? Thus we want facts and observers in condition to grasp them and to record them successfully.

It is easily understood that the first quality of an observer is to have acquired through study and in sufficiently great development the basic notions capable of enlightening him on the value of whatever he encounters, such that in the examination of facts no essential feature [9] escapes him, and that he includes in some fashion all possible perspectives [10] in their discussion. He must not apprehend these perceptions briefly or imperfectly, without distinction or judgment, or with that stupid ignorance which allows anything and takes close notice of nothing. In the habitual observation of nature one draws forth the auspicious secret of admiring without being amazed. But deliberate and attentive reading fashions strong measures which easily dispel the illusion of the first impression.

It must be admitted that several obstacles deprive us of these advantages. Those persons in a position to put their knowledge to account travel little, or do so for reasons foreign to the progress of Physical geography : those who find themselves in a situation within reach, for example, of an unusual periodic or mineral spring, or of a mass of shells and petrifications, neglect these objects either through ignorance or distraction, or lastly because the objects have in their view lost the sharpness of singularity and importance. Foreigners and travelers, even able ones, encounter them by chance, or visit them on purpose, but they cannot acquire a detailed and thorough knowledge upon one quick look. Superficial observations made in haste put objects forward in a quite imperfect way. They have not been seen with the composure, the tranquility of thoughtful consideration, with those details of interconnectedness so necessary for enlightening combinations. Hearsay or exaggeration of relations are substituted for what nature would show us with precision, should we consult it at leisure. It results from this haste that the most enlightened observers, naturally struck by the first indications of marvels, are often dupes of their surprise. They were unable to put themselves from the start in a favorable position; they distort the truth because they have seen poorly; and delivering too faithfully false impressions, they mix in with their accounts considerations which have seduced rather than enlightened them. If one is subject to error, even when one is a master of nature and forces it through experiments to reveal itself, to how many more mistakes and careless steps will one not be exposed when one is obliged to survey the vast extent of continents and seas, seeking nature in her proper place, and where she allows us to see only a very small part of herself, and often under conditions capable of misleading us?

An observer who is dedicated to this study by taste or because he is or has placed himself in a position to see, should begin by seeing much, considering from different aspects, familiarizing himself with objects so as to recognize them easily in consequence, and compare them beneficially. He should keep an accurate record of everything that makes an impression on him and everything that ought to make an impression. He should gather his observations in an orderly way without hurrying excessively to draw premature conclusions from the facts he discovers, or to reason about the phenomena that he perceives. That headlong haste that beguiles our self-regard is the origin of all false combinations, all defective inductions, all vague ideas by which objects as yet only incompletely studied are overburdened. In this way the aspects that are least clear are for this reason those lending themselves most to the urge to examine them.

Beyond this experience of poor outcomes yielded by hurried reflections, we have other reasons to refrain from them. As the attentive and deliberate inspection of our globe promises us an unbounded supply of absolutely new information and insights, an observer who begins to form a systematic harmony out of the small portion of facts he has gathered, seemingly treats as useless all the discoveries that one has good reason to expect from others sharing in the work, or to flatter himself that he is perceptive enough to be able to dispense with the elucidations these might be able to provide.

We further believe that the observer should be watchful against all bias, all settled notions resulting from an already contrived system. For in such a case, facts are interpreted following that scheme; one passes quietly by those considerations which are not very compatible with the favored principles, and on the contrary one expands those which appear to match them.

We do not contend, however, that observation occurs without design or without preconceptions. It is not possible for nature’s spectacle to fail to give rise to countless quite substantial ideas in a sagacious observer, who is precisely informed regarding discoveries by those preceding him, even regarding their strangest ideas. We admit that one can have a specified aim in one’s research, yet with a sincere intention to abandon it as soon as nature speaks clearly against the resolution that one had adopted provisionally. Thus one will not limit oneself to an isolated phenomenon, but will investigate all its conditions. These will be related minutely with that ardor for discussion that is inspired by the desire to find the relationship this phenomenon may have with others. While we condemn injudicious haste to build while observing, we do not want it forgotten that the materials that are gathered should naturally form part of a structure.

Such are the perspectives by which one may be led in the considered examination of facts. [11] But what should one see in the exterior appearances of our globe? What should command one’s initial attention? I answer that one must concentrate on exterior configurations, on prominently visible forms. Thus at first the configurations of continents, seas, mountains, beds, and fossils will be perceived; and in proportion as a greater number of these objects will be surveyed, as these configurations come to present themselves to our notice more or less frequently, they will produce in our mind durable impressions, recognizable characters we will not forget, which will give us basic ideas about the regularity of all these things. We will maintain an exact account of the circumstances and the places where they will have manifested themselves. And at length, by a continuation of such vigilance, we will be in a position to notice the varieties and all their interconnections.

Examination of these varieties, repeated and sustained upon a multitude of objects found under one’s feet when one knows how to look, allows us to distinguish easily the proper character of a configuration from incidental considerations. The extent of effects and even the combination of their causes are debated with much greater advantage, when it is possible to settle what they involve constantly, what they sometimes omit, and what they always exclude.

Irregularities are a source of illumination, because they reveal to us effects which are hidden from us or are made imperceptible by an excessively constant uniformity. Nature often betrays itself by a disparity which brings its secret into the light of day. But the irregularities can be used to advantage only insofar as one knows all about how such and such condition follows the uniform action of nature, and insofar as one can tell whether these divergences mark the essential or the incidental.

To have clear ideas about the things one observes, one concentrates also on enclosing within more or less definite limits similar effects, whether regular or irregular. One judges by exact measurement the maximum extent of a given contour, or the advance of a particular mountain salient, or the depth of a certain valley; whether these be formed out of beds that curve and continue in good order, or whether they be only the result of a sudden landslide. One notes down the dimensions of perpendicular cracks, [12] the thickness of beds, etc .

In judging the fixed limits of effects it is quite useful to pass beyond consideration of one extremity to consideration of its opposite, as for example from the height of mountains to the deepest abysses, whether on continents or in the oceans; or from the finest preservation of a fossil to the last stage of its calcination.

An intelligent observer will not limit himself so much in his learned discussions, involving an object’s exterior forms and its structure, as to fail to take into consideration also exact knowledge of the very materials out of which it has been produced. He will also link one idea accurately with the other. Such and such material, he will say, assumes such and such form; he will infer one from the other, and vice-versa. He will fashion general distinctions among terrestrial substances; he will divide them into vitrescible and calcareous materials; [13] he will recognize them by testing with nitric acid or through chemical reductions. He will have good reason to notice that sandstones occur in blocks and masses in their quarries; that limestones occur in beds and layers; that schists assume trapezoidal form; that certain crystallizations are subject to pyramidal or parellelepipedal shape; that in others the crystallized thin plates are assembled and adapted on a base toward which are oriented, as toward a common center, etc. All these subsidiary [observations] issue forth into details which by intensifying the observer’s attention place things in a new light, and give weight to his discoveries. [14]

He will apply the most scrupulous attention to the uniform and regular circumstances which accompany certain effects; he will not be able to miss them if he has been alerted to the influence their examination can have regarding the appraisal of phenomena. This consideration enters even more directly than any other into the object of Physical geography . Thus, following these insights, he will contemplate the works of nature, sometimes in their structural entirety, sometimes in terms of the relations of their parts. A general and rapid glance imparts only vague information; one scant detail often wears thin without yielding anything coherent. Thus it is necessary to support one observation by another; and so it is by having them follow by turns that insights are strengthened, even as they are extended. “This study presumes, says M. de Buffon, the grand views of an intense intellectual power which takes in everything at a glance, and the detailed attention of a laborious instinct which concentrates only on a single minute detail.” Histoire naturelle, vol. I . [15] The place occupied in the general economy by such and such body or such and such assemblage of bodies will be determined in relation to the nature of these bodies. In a word, the details concerning substances and their forms will be subordinated to those having to do with relative disposition. It will be noted exactly that certain beds of limestone or other materials are of constant thickness for their entire length, but that those of gravel amassed in valleys do not display the same regularity; that in the first, shells and other petrified marine bodies are flat, but in the second they are disposed quite irregularly; that perpendicular cracks are wider in soft substances than in more compact materials, etc . Whatever the multiplicity of agents driving nature may be, and the variety of forms it gives to its effects, nonetheless everything tends towards a harmonious whole. A foreign body which is found placed amidst substances of a different nature—a mass of talc within calcareous materials, blocks of sandstone amidst marl, sands amidst clay—all such observations are most essential for understanding the general distribution.

Since a single man cannot see everything by himself, and because the condition of our knowledge owes its progress to discoveries and to combined researches of several observers, it is necessary to rely on the testimony of others. However, among these outside descriptions there is much to choose from; and in this discernment one must invoke serious criticism and severe examination. Experience and reason warrant our general distrust of all facts of this kind which are vouched for only by the ancients; we will not rely on these, we will take an interest in them only as subject to verification, or only insofar as verification has been forthcoming and as they will have been stripped of the spirit of the marvelous which those writers usually ascribe to them; or at least only when the details are brought back within the domain of confirmed and unquestionable conditions. We believe that there should be proscription in particular of all the famous falsehoods which, through blameworthy negligence or idiotic credulity, have been passed down across the centuries, and which pass for being true. One can judge from the frequent use of these that compilers allow themselves, how much harm they do to the Sciences. However, to exclude them permanently, we must be in position to put truth in their place; and often this is corrupted by the most bizarre ideas. One is entirely undeceived of an illusion, only when one understands the assumptions that underlie it.

As regards authors who wrote before the renewal of the Sciences, they should be consulted only with caution. Deprived of the knowledge which might have enlightened them and guided their discussion of the facts, they took it into account only imperfectly or from a viewpoint corresponding solely to their presuppositions. Kircher describes, draws, shows sections of subterranean reservoirs that are useful, according to him, for the passage of sea water to springs. With the best faith in the world he relates marvelous details of disappearing whirlpools in the Caspian Sea, [16] of the central fire, of subterranean caverns, as if he had made sustained observations regarding these objects, which are accepted in our time only through credence in rash writings by authors of comparable judgment. [17]

In general, observers who are ignorant, or biased, or inattentive, who see things rapidly, without purpose, and without thoughtful consideration, deserve very little credence. I want to find in the author himself, in the details he presents, that good faith, that simplicity, that abundance of insights, which inspire in me confidence in his observational talent, and in the accuracy of his narratives.

Often observation forsakes us on certain complicated subjects; it is not precise enough; it reveals only a portion of the effects, or shows them on too large a scale to authorize an assertion which might bring order to our thinking. In such cases experiment is indispensable. [18] One must resolve to follow nature’s operations with a constancy and obstinacy that nothing can discourage, especially when one is confident of being on the right path. Without this resource there is no basis for reasoning knowingly from facts. All the observational details cannot be brought together with the precision that is so desirable in the Sciences, and they will lead only to vague consequences and gratuitous suppositions, which amount to our own decisions rather than those of nature. Such is the case, for example, as we have noted in the article Spring, of the observation of the quantity of rain falling on different parts of the earth, and comparison of this with the mass of waters circulating in the same area. On this depends the resolution of everything concerning the origin of springs, the distribution of vapors over the continental surfaces, and running water. Although one may have assembled all the facts, gathered together all the most interesting observations, still one cannot, without the exact results of experiments, pronounce at all decisively on these important matters.

Principles whose purpose is the combination of facts . Since individual and isolated facts indicate only vague things, it is necessary to interpret them by drawing them together and combining them.

Today more than ever people realize that it is almost as important to bring order to discoveries as it is to make them. Without this resort the scattered features which portray nature would escape us. Nearly all phenomena, especially those which we have in view, have utility only insofar as they may relate to others; in similar fashion, the letters of the alphabet, which are pointless in themselves, when joined together form words and languages. Moreover, nature does not reveal itself completely in a single fact or even in several. A solitary phenomenon can only be put in store in the hope that one day it will be joined with others of the same kind. And since within nature’s scheme such a fact is impossible, an intelligent observer will find few of this sort. In a word, an isolated fact is not a physical fact. And true Philosophy consists in discovering the relationships hidden from shortsighted eyes and inattentive minds. A striking example will bring home the accuracy of these principles. Father Feuillée had observed “that rock sections near Coquimbo, in Peru, were perpendicular to the surface; that those going from east to west, and others going north to south, crossed at right angles, that the first sections were parallel to the equator and the others to the meridian.”  [19] If this learned monk had been guided by the ideas we are outlining here, far from saying as he does that nature had thus configured mountains for this part of the world, already so rich in mines, in order to make it more perfect than others, he would have conceived the plan of acquiring corresponding observations on the other continents, and would not have confined himself to the fruitless consideration of final causes. See Final causes. This well-contrived idea has since that time won M. Bourguet the discovery of corresponding angles, etc. [20]

Thus it is easy to sense the necessity of combining facts. This delicate operation is carried off on two different levels. There is a combination of order and collection; and there is a combination of analogy.

In proportion as one accumulates facts and observations, these would make one rather more overwhelmed than enlightened, if one had not taken care to reduce them to certain classes defined more by the subject than by their natural linkage. For without multiple researches, one has only scattered links which do not yet indicate the mutual correspondence that can make possible at some point an uninterrupted succession. Nonetheless since there is always need of a certain appearance of order, one settles for placing things in incorrect arrangements. [21] Truth will emerge better through this minor artifice than through confusion. [22] Time and research will rectify the one rather than augment the other.

It must also be admitted that these general compositions, although imperfect, would be more conducive to our present work, which is to secure information for posterity’s use, and better suited to our limited and imperfect knowledge on certain complicated subjects which have thus far received no more than a first sketch, than those garbled notions to which imagination gives the form and appearance of a theory. These tables would be like archives for discoveries, the depository of acquired knowledge, open to everyone who would find in themselves the will and ability to enrich it anew. Future observers will review there at a glance and with clear precision, what we sometimes spin out in a confusion of strange and bizarre ideas, which the greatest wisdom disentangles with difficulty.

This first operation would lend itself greatly to easing the second: Contemplating simplified facts, classified in a certain order, one is more readily enabled to grasp their mutual relationships and what may join them in nature. This arrangement would apply not only to observations we draw from others, but also to those we would have made ourselves.

Thus we would benefit greatly from this classification of phenomena, in order to grasp their relations. But it must be admitted that when we have become familiarized with the objects themselves, and have acquired the habit of seeing them with intelligence, they will form in our mind some of those durable impressions, and will present themselves to us with those corresponding characteristics that are the foundation of analogy. We will rise gradually to more general perspectives through which we will encompass several objects at once. We will grasp the natural order of the facts. We will link phenomena together. And we will oversee at a single glance a series of analogous observations, the evident interconnections among which will continue effortlessly.

But a first condition for arriving at this viewpoint is to have observed scrupulously each of the compared objects. Otherwise one cannot apprehend properly the precise limits of the relations that might join them. If we have been exact in disentangling what might reconcile one fact with another, and in discovering whatever in the phenomena would reveal a marked tendency toward agreement in organization, thereafter analogies will come to our mind of their own accord.

It often happens that we allow ourselves to be beguiled in the course of our observations, either by negligence, or by prejudice based on a system. Consequently, we have the self-conceit that we see beyond what nature shows us, or we hesitate to perceive everything that it might allow us to discover. In accord with this illusion we imagine resemblances between altogether dissimilar objects, regularity and order in the midst of confusion.

In all these transactions, the main skill is not to make up for a deficiency of facts, but to combine the details that are known of them; to conceive possibilities, but to know how to discover them. Indeed, in proportion as one increasingly studies nature, its mechanism, its art, its resources, the multiplicity of its means of making things happen, even its apparent disorganization, everything amazes us, surprises us. In a word everything inspires that caution and wariness which moderate the unguarded tendency to indulge in our initial ideas or to follow our first impressions.

So as not to be hasty, it will therefore be quite prudent to apply ourselves only to the most immediate relationships, and to make use of those which have been perceived and verified exactly, to raise us up to others. For this purpose, we put our observations in order, and we make new ones when we lack intermediary connections. We are careful to avoid linking facts without having surveyed all those standing between, through an induction wherein nature itself guides the chain. Far from encumbering complicated matters with marvelous or strange features, we will pick them apart by a kind of analysis, so as to limit ourselves to comparison of the parts; and in proportion as we advance in this task, we will recompose anew the parts and their relationships, so as to enjoy the effect of the whole.

Thus we will apply ourselves first to analogies of external forms, then to those of the forms of masses or internal configurations. Finally, we will examine analogies of circumstance. I have followed the contours of two mountains running in parallel; I have noted the correspondence of their salient and re-entering angles; I press into their mass, and I discover with surprise that the layers which collectively form the solidity of these angular projections are subject to the same regularity as the externally visible layers. I draw the same analogy of regularity as regards the external and matching directions of the ranges, and as regards the corresponding organization of the masses. This is not all: I say that the external form of mountains when considered unto itself has a marked relation of dependency with the orientation of the beds entering into their interior structure. I will even extend my analogies into the nature of the materials, and their corresponding altitudes, and I will observe, as a noteworthy circumstance, that the angles are more frequent and more acute in deep and more confined valleys, etc.

An important point on which I will insist will be not to lose from sight nor to conceal the most noteworthy differences, or the slightest exceptions, that may present themselves to my view within the range of relationships I will have occasion to apprehend and to note down. The relations I will establish as a result of this vigilance will be less indeterminate. And in accord with this scheme I will even be in a position to establish new relationships and suggestive combinations among these various possibilities, when they present themselves with decisive features marking their resemblance. In this way I will not allow myself any kind of assumption. And far from being tempted to extend relationships beyond what the facts show me, in a case where an exception might seem to fit poorly, the hope I will have to use it one day with success will lead me to refuse to conceal or disregard it, as I might have been tempted to do, if I had regarded it as pointless. With such an exception providing me the opportunity to draw out of it a new class of variables subject to regular effects, wouldn’t my observation be more advantageous for progress in Physical geography than if I had assumed, through the help of an easy illusion, uniform regularities?

Only through such precautions will it be possible to gather an integrated series of analogous facts, and to make out of them an aggregate in which the mind can easily envision a methodical structure of clear ideas and fruitful relationships.

Principles for the generalization of relationships . So it is the case that facts which are thoroughly established, precisely delineated, and wisely combined, serve us as a source of light guiding observers in the study of other facts, preparing for them a coherent succession. By dint of perceiving particular effects, by studying and comparing them, we draw from their affinities placed in a new perspective fruitful ideas which expand our vision. We rise gradually to broader things. It is in these delicate circumstances that method is needed to guide the mind. When it is necessary to follow and unravel at a firm and assured glance the proceedings of nature at large, and in some way to gauge the adequacy of one’s outlook in relation to the vast extent of the universe, shouldn’t one have worked for a long time to rise to a favorable viewpoint from which it is possible to discover this immensity? Thus we have emphasized the preliminary stages of this great operation.

Generalization therefore consists in the establishment of certain pervasive phenomena, which are drawn from the common and distinctive character of all perceived affinities among facts of the same kind.

Especially to be regarded are the most fruitful affinities, those most suggestive and most clearly outlined, in a word those whose nature most often offers us terms of comparison: such are the subjects of generalization. As regards its [nature’s] processes, it [generalization] directs them toward the course of nature itself, which is always delineated by an uninterrupted progression of facts and observations, drawn up in an order depending on combinations already perceived and established. Thus facts are found (by measures pointed out in the two previous articles) arranged in certain general classes, with that feature which unites them, which serves as their common bond: a feature that has been understood in detail, that one considers then from a single perspective; a character after all which makes palpable the collectivity of facts, in such a way that the outline of their explanation is made evident by their natural dispositions. By this way of understanding the observer has command of all his researches; he perceives with satisfaction the admirable harmony and unity, the natural order, the methodical interconnection which seemingly intensifies a phenomenon, through its correspondence with those found in similar circumstances.

Profitably drawn from this generalization are abiding principles, which may be regarded as the essence extracted from a rich store of observations which serve in place of proofs and reasoning. These principles are suggestive points of departure to clarify anew certain subjects by analogy. And as a result of the regularity of nature’s operations, new facts are born from these which arrange themselves in systematic order. To us these principles are laws of nature, under whose rule we submit all subordinate phenomena. Like the answer to a riddle, they offer with brilliant precision more play and ease to the observing mind, so as to extend knowledge. Finally, they have this very important benefit, to undeceive us on countless distorted or absolutely false facts. Such facts will disappear or be rectified to proper condition, just as it is easy to correct a printing error when one grasps the meaning of the text.

But to establish these general principles, which are actually only general effects regularly perceived in the discussion of combined facts, it is necessary for the generalization to have been rigorous and exact, that it have had for its basis a numerous and varied series of facts linked tightly, continually and without interruption. Without this precaution, rather than principles built on facts and realities you will have general abstractions from which you will be unable to draw any fact found in nature. What use can there be in principles which are not the seed of discoveries? And how can anyone want to see an idea foreign to nature as the means of its resolution? It is only by what you extract from nature’s store, and what it has allowed you to see, that you can reliably unveil what it hides from you.

If the induction by which you have generalized has not been informed by a large number of observations, the general result will be too broad; it will not encompass all the facts that it should cover. And the cause [ principe ] underlying this drawback is that blameworthy haste which—rather than fearing exceptions where facts are lacking, where knowledge from facts abandons us—is allowed to work from plain groundless suspicions of some constant regularity.

It is easy to see that such a mistake occurs only because in argument over the facts the essential has not been distinguished from the incidental, and because in the recitation and combination of phenomena a linkage was formed without understanding its exceptions. What was required was an accounting of these exceptions, as accurate as is done for the expedients underlying analogies.

On the other hand, I note that vague and unspecific observations are useless for establishment of any principle. All our investigations should have the goal of checking and appraising all facts, and to give above all a form of accuracy to the results. Without this sort of attention, there is no certain knowledge, no generalization, no general results.

Principles are often stretched too far, because they were developed from ambitious standpoints, imposed by a pet hypothesis. For then in the whole course of making observations common exceptions have been evaded, by being overlooked or through subtle distinctions. These have been neglected as unavailing, and in the midst of such obstacles, generalization of results has always been sought as the goal. In the course of things if contrary facts are found, these are adjusted, as though they were obliged to accommodate themselves to an excessively general rule.

Other results often appear with countless modifications and restrictions, raising a concern that they may be subordinated to still others. The reserve with which one is obliged to make one’s principles known comes from a shortage of observations. The only measure to be taken to assure the soundness, breadth, and accuracy such principles deserve to acquire, is to consult nature. Otherwise, principles whose generalization is not full and complete, whose application is not stable and firm, will continually be a source of mistakes and fallacies.

It is only by relying on facts inquired into with care, bound together with wisdom, and generalized with judgment, that one can hope to pass on to posterity robust truths, general and incontestable results, in short fruitful and suggestive principles.

II. In casting a first glance over our globe, the most general division that shows itself is that by which one understands it as divided into great continents and seas. As in the part covered by water there are several points of land that rise above the waves, which are called islands , similarly in passing over the continents one notes spaces covered by water. When these are stable they are called lakes ; when they flow they are rivers or streams .

The two broad parts of fixed land and of seas extend into each other reciprocally, and in different directions. In the diverse relative configurations of the boundaries circumscribing these two parts of our globe, one observes that the sea encloses on all sides four large continents, and that it penetrates into the land’s interior in several places. These are Mediterranean seas, gulfs , bays , and coves . [23] On the other hand, continents are constituted with considerable projections into the sea basin; these are capes , promontories , peninsulas . The narrow channel in which the sea runs between two landmasses forming gulfs is called a strait . There are three kinds of straits, insofar as the land is considered that forms the shores of the channel. Either these two billows of land both belong to one continent, or one is made up of continental land while the other is an island, or finally they are opposing coasts of two islands. Considered in a different way, straits can be regarded as forming a communication from one basin to another, and among these it is also possible to distinguish three kinds: those connecting one sea with another, such as the strait of Magellan; from a sea to a bay, as that of Bab-el-Mandeb, which connects the Arabic gulf to the Indian Ocean;  [24] or finally connecting one bay with another, such as that of the Dardanelles. There are gulfs that extend lengthwise, while others are rounded at their extremities, showing a wide opening without other straits, other than those occurring between an island and a continent, or between two islands. Examples are the gulfs of Mexico and Bengal. And some divide in several branches, such as the Baltic Sea.

A narrow strip of land between two seas is called an isthmus . Isthmuses join together large continental portions with others, and peninsulas with continents.

Resuming these ideas, I place in opposition continents and seas, islands and lakes, gulfs and peninsulas, straits and isthmuses. These are corresponding and opposite configurations, which it is good to conceive from this standpoint of opposition.

In examination of the globe’s general properties , which we have just dissected by pointing out the nomenclature of its different configurations, it is necessary to follow some scheme.

1. We will present first the general results of observations which are directly related to the globe’s constant and regular organization, and we will consider this subject from two different viewpoints: external organization and internal organization.
2. We will be concerned with the general phenomena which appear to show a change in that constant organization.
3. Finally, the terrestrial features depending on the atmosphere and different aspects of the globe in relation to the Sun and Moon will be the substance of the third section.

General properties of the globe’s external organization . Solid ground comprises four large continents: (1) the old world, (2) the new world, (3) the southern lands, known or suspected, (4) the arctic lands, whose separation from America is not yet well established; the configuration of the australian lands is even less well known. Therefore, we will limit ourselves to reasoning about the old and the new continents.

Looking carefully at the old and new continents, it is observed that the old world extends farther to the north than southward from the equator, and that, by contrast, the new world reaches farther to the south than north from the equator. It is also seen that the old continent’s center is situated at 16 or 18 degrees of north latitude, and that of the new continent at 16 or 18 degrees of south latitude. This center is defined by the intersection of lines drawn through the continents’ greatest lengths and breadths. [25]

Further, the old and new continents have this noteworthy feature, that they appear as if divided into two parts, so that all four parts are surrounded by water, and would form distinct continents, were it not for small isthmuses or constrictions of land: those of Suez and Panama. The first is produced partly by the Red Sea, which is like the appendage and extension of a large gulf projecting into the land from east to west, and in part by the Mediterranean. The other is similarly produced by the Gulf of Mexico, which displays a wide opening from east to west.

Bacon remarks that it is not without some reason that the two continents widen greatly toward the north, narrow toward the center, and extend into a quite sharp point toward the south. It can be added as well that the extremities of all the large peninsulas formed by projections of continents look toward the south, and that some of them are similarly cut by straits whose channels are directed from east to west. [26]

If we journey now on the dry part of the globe, what we will notice first are different inequalities of its surface, long mountain ranges, hills, valleys, plains. We will perceive that the diverse parts of the continents display quite regular slopes from the center, or from the high summits of the chains that cross them, as far as the sea coasts, where the land goes beneath the water to form the deep of its basin. Reciprocally, in going from the sea coasts toward the continental center, we find the land rising up to points that dominate the surrounding lands on all sides.

Let us dare to sound the depths of the sea; we will find that depth increases in proportion as we distance ourselves from the coasts, and contrarily it decreases as we approach them. Thus the sea bottom by gradual elevation overtakes the lands rising above the waves. By this same study we will find that the vast extent of the sea basin shows inequalities corresponding to those of the continents. It has its valleys and its mountains. Rocks at water’s edge, and islands, are only the highest summits of mountain chains that in varied branches crisscross the global areas covered by the sea.

I take note that the sea waters, spreading into great valleys where the terrain is subject to the steepest slopes, have formed gulfs , Mediterranean seas; and that conversely, lands undergoing irregularity in their lowering toward the sea coasts, and lending themselves less to the curving of lands which plunge beneath the waters, project into the midst of the waters, and form capes , promontories , peninsulas .

Let us now enter into greater detail, and let us examine more closely each object whose different particularities escape us in the remote view where they have been presented.

We recognize first that all mountains form different main ranges which interconnect and unite, and compose the surface of the continents, as much by their main trunks as by their subordinate branches. Mountains, which are really the main trunks, display very considerable masses both by their height and by their volume. They ordinarily are in the center of the continents they cross. Those of lesser altitude branch off from these main chains. They gradually become smaller as they become more distant from the trunk, and proceed to vanish either on the sea coasts or in the plains. Others continue along the sea coasts, or at a certain distance from those shores.

In a given mountain mass in a specific part of a continent, there is always a point of maximum elevation with other summits showing discernibly lower altitudes, both in the direction of the range’s prolongation on each side up to a certain distance, and following the collateral branches.

The highest mountains are between the tropics and in the middle of the temperate zones, and the lowest neighbor the poles. Between or near the tropics there are the Cordilleras in Peru, the peaks of the Canaries, the Mountains of the Moon, the great and lesser Atlas, Mount Taurus, Mount Imaüs, [27] the mountains of Japan. The Cordilleras are almost twice as high as the Alps. The old continent is traversed from Spain as far as China by chains parallel to the equator; but they give off branches which, directed southward, cross and form different peninsulas, such as Italy, Malaya, etc. The Alps ramify in the north of Europe, as do the Caucasus in the north of Asia. The great and lesser Atlas are also parallel to the equator. But it is to be presumed that they link with other chains directed also toward the south, to form the tip of the Cape of Good Hope. In America the bearing of the mountains is from north to south.

Mountain slopes, whether along the axis of their chains or as regards collateral branches, [28] are much steeper on southern sides than on the north, and much longer toward the west than toward the east. Precipices are more common toward the south and west. Plains have an insignificant slope, as do summits, toward the east and north.

If a close examination is given to the configuration of these different mountains, which we have just reviewed on a large scale, some very curious phenomena will be noticed.

The sides of these ranges display substantial assemblages of land, or angular advances whose extremities make a right angle with the bearing of the mountain chain. Thus in a range with a north-to-south direction the angles will extend on one side to the east, on the other to the west.

When two ranges bear and run parallel to each other, in the area between them they form elongated defiles and figured valleys, like the banks of a channel dug by running waters, such that the salient angle of the one is opposite the re-entering angle of the other. [29]

The angular advances or assemblages are more common in deep and narrow defiles or valleys, and their angular extremities sharper. But when the slope is gentler, the mass resting then on a wider base, the angles are more obtuse; they are also farther apart. This is what happens in valleys opening onto wide plains.

In general, several parts are distinguished in a mountainous mass. The highest parts are made up of peak-like or conical features, usually stripped of soil. At the foot are found plains or valleys of varied extent, which are actually planed-down tops of other mountains, which show on their crests different recesses, and which are backed up against hills whose angular advances at length vanish in the extended plains. Thus we see that there are two sorts of plains: low-lying plains, and mountainous plains.

If a trans-continental mountain range approaches a coast while sustaining moderate altitudes, it carries on beneath the surface, and forms islands in its highest points, usually following its initial direction. Sections of the continuation of these marine ranges make up shallows, reefs, and water-level rocks, such that these protuberant masses discernibly mark the route that mountain ranges follow beneath the water. There are signs that this happens with little interruption. [30]

Consequently, straits are simply the natural lowering or else the forced interruption of mountains, forming promontories. [31] So their prolongation recurs in islands separated by straits. And their appendages are always subject to the alignment of the ranges crossing the continents. As a result of this same disposition, straits are places where the sea has the least depth; a prominence is maintained from one side to the other. And the two basins that are connected by this strait increase in depth in steady progression, as can be seen in the Strait of Calais. [32]

This correspondence in mountains is quite readily seen in islands of a certain length located near continents. They are separated into two segments by a quite distinct trans-continental eminence running in the direction of other islands or continents, which as it diminishes in height from the center to the extremities on each side, gradually sinks beneath the waters. The same thing applies to all promontories and peninsulas. The mountain ranges traverse them along their greatest length and through the middle. Examples are Italy, the Malay Peninsula, etc.

Land separating two seas and forming isthmuses is subject to the same regularity. Isthmuses are actually just extensions of mountain ranges sustained at a certain height, with their angular advances or collateral masses, although less substantial than the extended masses where continents widen out and separate the waters in broadening. The isthmus of Panama is thus formed by the lowering and narrowing of the Cordilleran range, which continues from Peru to Mexico.

A result of the dependence of sea-basin configurations on the prolongation and bearing of mountains is that the sea depth on the coast is proportionate to the height of that same coast, and that if the beach is low and the land flat, the depth is little. It is easy to see the reasons for this. A high promontory descends beneath the sea level by an abrupt slope.

Three types of coast are distinguished: 1. High coasts made of rock or hard stone, usually cut vertically at a considerable height. 2. Low coasts, one kind being even and of gradual slope, the others of medium elevation, and bordered by rocks at water level. 3. Dunes composed of sand that the sea accumulates.

Another consequence of the globe’s external structure, bristling with mountains, is that between the tropics there are many more islands than anywhere else. We have noted as well, in regard to the continents, the highest mountains are in this part of the world. So the largest surface inequalities are in fact in the vicinity of the equator.

These big assemblages of islands which display a multitude of points at small distances from one another are close to the continents, especially in the great embayments formed by the sea. Solitary islands are in the middle of the Ocean. [33]

If we explore what the Ocean shows us moreover, we will discover different regular and constant motions which stir the mass of its waters.

The main one is that of the flux and reflux, which in twenty-four hours lifts the waters toward the coasts two times, and lowers them in an alternating fluctuation. This is in constant correlation with the course of the moon. The swelling of the waters is more noticeable between the tropics than in the temperate zones, and more evident in narrow and long gulfs open from east to west, than along wide and low-lying shores. This is modified lastly depending on the bearing of the land and the height of the coasts. [34]

A result of this first motion is a continual and general tendency for displacement of the entire mass of the Ocean’s waters from east to west. This movement is seen not only between the tropics but also throughout the whole extent of the temperate and frigid zones that have been navigated.

Certain particular and accidental motions are noticed in some localities, which appear to depend on the general movement of the flux and reflux: namely, some currents. Some are constant and extended in both length and width, and are directed in a straight line. Often they undergo several curves and changes of direction. Some are swift, some slow. They produce some swirling waters or whirlpools, such as the Maelstrom near Norway. This effect results from the concourse of two currents meeting obliquely. When several currents come together, these produce great dead calms, turnings where water seems subject to no motion at all.

One last observation regarding the Ocean has to do with its salinity. All sea water is salty and mixed with a bituminous oil. It contains about one-fortieth of its weight in salt, with some variations for gulfs, which receive much fresh water brought there by continental rivers.

This observation naturally brings us to consider questions about still water and flowing water on the continental surface, to gain a grasp of their most general phenomena.

I take note first that the main sources of rivers, and the origin of the channels carrying continental water to the sea, are located either in the body of the main ranges crossing the continents, or near their collateral branches. I perceive in different parts of the continents elevated regions which act as dividing points for the distribution of water flowing in different directions to the sea or into lakes. [35] I see two main ones in Europe, in Switzerland and Muscovy; in Asia, in the land of the Chinese Tartars; and in America, the province of Quito. Aside from these main ones, there are others ever subject to collateral mountains. And finally certain streams take their sources at the feet, or in recesses, of mountains ranging along the sea coasts.

Springs or fountains can be distinguished by the phenomena their flow displays, and by the properties of the waters they pour forth. As regards their flow, three kinds are distinguished: 1. Continual springs, which undergo no interruption or any marked diminution. 2. Intercalary periodic springs, which are subject to regular diminution but without interruption. 3. Intermittent periodic springs, which have interruptions of varying lengths. See Spring.

Regarding the nature of their waters, there are mineral waters, loaded with metallic particles; lapidific waters laden with earthy particles; and clear or turbid waters; cold or hot waters. Others have particular odors and tastes. See Hydrology.

When several springs lack a slope favorable to forming a channel, their waters gather in a basin with no outlet, and this yields a lake. Sometimes the water overflows the basin and spreads beyond. Or alternatively when a stream in its course finds no way open to the sea, its waters cover a more or less extended area depending on their abundance, forming a lake. In accord with these considerations we distinguish four kinds of lakes: 1. Those not discernibly receiving water from any channel, and not losing water from any outlet. 2. Those without any inlet channel, but which supply water to rivers and streams. 3. Those which receive incoming rivers without interrupting their course. 4. Those receiving incoming river waters and collecting water without any outlet. Examples of this last kind are the Caspian Sea, the Dead Sea, Lake Morago in Persia, Titicaca in America, and several lakes in Africa into which rivers flow from over a vast extent of the land [ pays ]. These lands [ terreins ] constitute an exception to the general sloping of continents toward the sea.

Lakes located along the course of rivers, or neighboring such courses, or which have outlets, are not salty. By contrast those which receive rivers without any outflow are salty. Rivers flowing into such lakes have continually brought along all the salts they have extracted from the soil. Lakes having no incoming river and no outlet are ordinarily salty if they are near the sea; they are freshwater if they are distant from it.

Most lakes seem to be dispersed as well in greater numbers near those kinds of dividing points we have noted on continental land. In Switzerland I find as many as thirty-eight. The same thing occurs in the drainage divide in Russia, in that of Chinese Tartary in Asia, etc.

But I note generally that mountain lakes are all surmounted by much higher land, or are at the base of peaks and at the tops of lower mountains.

As rivers always flow from higher toward lower places, from main or collateral mountain crests toward sea coasts or into lakes, it follows naturally that the direction of summits and extended ranges is marked by a sequence of points where all flowing water channels take their origins, and by an intervening area they leave empty as the channels distribute themselves toward various seas. [36]

Thus the crests of the main ranges, collateral branches, even hills of middling size, all serve to constitute those drainage divides we had discovered and generally traced. In this way the Cordilleras distribute water toward the Southern Sea [37] and to the vast eastern plains of south America. The Alps similarly distribute waters toward various seas by four different channels, the Rhine, the Rhone, the Po, and the Danube.

It is readily seen, in accord with these general observations, that streams and rivers are channels that drain water spread over the continents. I note that rather than ramify into several branches, to the contrary they join their waters together, and carry them in bulk to the sea or to lakes. I see only one exception to this general disposition, namely the communication of the Orinoco with a stream that flows into the Amazon. Men have taken advantage of this kind of anastomosis, by connecting those river beds by waterways. What will the partisans of final causes tell us about this?

Through their entire course the direction of rivers is constrained by the configurations of mountains and valleys where they flow. Thus when one of the mountains alongside a valley has a less steep slope than the one on the opposite side, the river takes its course closer to the side with the steep and precipitous flank, not keeping to the middle of the valley. It occupies the middle only when the slopes are equal. Rivers follow the main mountains where they take their origin only to the extent that they are restricted between two ranges. But once they spread into collateral lowlands, they flow perpendicularly to the direction of the ranges, following mountain valleys of secondary and tertiary size, where they meet other streams that enlarge their volume. As a result of the steeper gradient that rivers find as they leave mountainous plains, [38] they usually meet in the interior, the direction of their channel is usually straight for a certain distance, and their curves become more frequent only as they approach their opening to the sea. It is noted that large rivers flow perpendicularly to the coast where they reach the sea, and that they are joined by streams on all sides, showing a marked gradient on both sides. In the rounding of certain gulfs, you note a similar rounding in rivers flowing into them as they are arranged as if toward a common center, their mouths widening along the whole contour. These mark the valley forming the gulf. This disposition is marked in rivers flowing into the extremity of the Gulf of Bothnia.

A regular and constant phenomenon is the periodic augmentation undergone by a large number of rivers, and especially those with sources between the tropics. They cover neighboring plains with their waters to a great distance. Others undergo only those irregular and sudden rises in their waters following snowmelt or heavy rain. Some are swift, others have a calmer flow of water. And all other things being equal, this appears to depend on the distance from source to mouth. Thus of two rivers which start at the same divide, going to the sea by different routes, the swifter is the one whose course is shorter. Some others are lost in sand, or disappear underground. Finally, I note in mouths of large rivers some islands and heaps of sand dividing the channel into several arms.

General properties of the internal and regular structure of the globe . What strikes me at first in digging into the earth, is that its mass is composed of beds and layers, whose thickness, direction, etc., are subject to regular and constant dispositions. [39] Wherever one digs, one encounters these layers or beds of different thicknesses, from one line up to one hundred feet. [40] And the more one excavates in the globe’s interior, the thicker the layers are. These layers and beds also cover a very large area of terrain in every direction. With the exception of the layer of topsoil, all these layers rest in parallel atop one another; and each bed has the same thickness throughout its entire extent.

The beds of earthy materials which are parallel to the horizon in the plains rise and flex with the crests of the mountains they form and pass through, and go on then to descend into the valley below. If the mountain slope is gentle, the tilt of the beds is quite high. If the mountain flank is steep, either the beds are cut vertically and interrupted by landslides, or else they descend almost without bending downward, and reach the plain. [41]

When at a mountain’s summit the layers are level, all the others composing its mass are even as well. But if the summit beds lean over, the mountain’s other beds follow the same incline.

In certain narrow valleys formed by steep mountains, the vertically sliced layers seen there correspond across the valleys as regards their height, thickness, disposition, and material composition, as if the mountain had been severed through the middle.

In masses of figured mountains, [42] the internal beds in salient or re-entrant angles undergo the same disposition as the external contours. Thus the phenomena of the surface seemingly are linked with those of the internal configuration, and show this to us. [43]

The same regularity occurs as regards two hills in parallel succession. The same beds continue from one to the other in good order, while flexing beneath the valley. It is good to observe that the level does not obtain for the height of corresponding layers, except when the two hills have a similar height; which is the usual case.

It must be said, however, that this organization does not show itself in this way everywhere. The highest mountains, whether on continents or on islands, are really only peaks or cones of solid rock, sandstone, or vitrifiable materials. [44] Those whose summits are flat contain marble, limestone. Hills whose mass is of sandstone display everywhere irregular points indicating layers with little continuity and a heap of debris. Those composed of calcareous materials, marble, limestone, marls, etc. have a more rounded and less regular shape.

In accord with the different observations whose results we have just outlined, eight positions and different forms can be distinguished in terrestrial layers; those which are: 1. parallel to the horizon; 2. arranged in perpendicular; 3. variably tilted; 4. bent in a concave arc; 5. bent in a convex arc; 6. undulating; 7. rounded; 8. angular.

These different forms appear to be dependent on the bases on which the beds or measures rest. [45] Looking through the layers’ arrangement, it has not been found that the materials forming them are ordered in accord with their specific gravity. [46] The layers of heavier material are positioned over layers of lighter material. Some massive rocks lie on top of sands or clays.

Beneath the sea, in straits, and in islands, terrestrial materials are found ordered in layers, as they are on the continents. In certain straits it has been found that the sea bottom consists of the same sort of rock as layers serving as the base of the elevated coasts forming their channel. On both sides of the strait the same layers and same materials are seen, similar to the two steep mountain flanks that form a valley. In other straits, layers of the two sides of the channel pass gradually beneath the water, joining together.

The materials making up the globe’s primary layers are ordinarily divided into two general classes: the first comprises vitrifiable substances; to the second belong calcareous materials. Either alone, or in a mixture, these materials make up the soils, stones, metals, and minerals of all kinds. It is not part of our purpose to go over these in detail. We concern ourselves with these diverse materials only insofar as we are interested in their relative dispositions as regards the globe’s internal structure.

Clays, sands, schists, coal, solid rock, extended sandstones, marls, limestones are all laid down in beds and layers. [47] But tuffs, small masses of sandstone, pebbles, [48] crystals, metals, minerals, pyrites, sulfur, stalactites, and incrustations are all found in irregularly arranged masses, lodes and veins, although subject all the same to certain shapes, especially crystallizations and salts.

But, among the materials constituting terrestrial layers, what has especially drawn the attention of observers is the considerable multitude of fossils, plain or petrified. [49] One finds shells of different kinds, and skeletons of ocean fish, that are identical to the shells and fish presently living in the sea. By their gloss, their colors, their natural enamel, these fossils exhibit recognizable remains of animals. The shells are whole. Everything is similar, both inside and outside, within the chamber, in their convexity, and in substance. Configurational details, the smallest articulations are shown clearly there. Shells of the same species are found in groupings, small and young ones attached to large ones. And all are in heaps and beds laid down flat and horizontally. Certain shells appear to have undergone a kind of calcination of varying degree, and decomposition altering their form to a large extent. They occur in imperfect condition, disfigured, in pieces.

The beds of fossils found in different places cover very considerable expanses. There is a mass of over one hundred thirty million cubic fathoms of them in Touraine. [50] In most stone quarries this material dominates and binds the rest. As for petrifications which show only impressions, whether in relief or as a mold, of animals or of plants, these are of a stony material, metallic, and variously colored. Some of them display flawless form, while others are broken, bent, flattened, or stretched.

In short there exist in the layers of both mountains and plains an astonishing multitude of fossils, whether conserved, altered, or petrified; in mid-continent, as well as on islands; in surface beds, as well as in the deepest layers; from the summit of the Alps, to a hundred feet below the surface of the ground at Amsterdam; [51] through the entire mountain range crossing the old continent from Portugal all the way to China; in the lightest materials, and in the hardest and most compact substances. These fossils are enclosed, petrified, and filled with the same materials that envelop them. In a word both light and heavy fossils exist in the same materials; in a single place, the most varied kinds; in the most distant places, the most closely similar kinds, whose living analogues both plant and animal are known both in faraway seas and in nearby waters, or are not yet discovered.

It must be noted that there are more shells and petrifications in calcareous materials, in clays, and chalky stone, etc. than in vitrifiable materials. Some are found dispersed in sands. Shells have not so far been seen in small masses of sandstones or hard rock. And no shells have yet been discovered in the Cordilleran mountains of Peru.

The disposition of all these layers whose form and substance we have just considered serves for the regular gathering and distribution of rainwater, for its storage in different places, and its flow through springs, which actually represent the disconnection and extremity of a natural aqueduct formed by two beds of material suited to convey water. For as water falls on these beds, filtering in by openings and through the common breaks occurring in them especially where they are flexed, they often become charged with molecules of earthy or metallic materials which may dissolve, acquiring by this operation the varied qualities we have already noted. Beds of clay or sand predominating over a large part of the globe contain water. The gradient of beds makes the water flow; and depending on the depths of the beds, water collects either near the earth’s surface or at great depths. A lake is simply a gathering of water flowing between beds which come to an end at a basin, taking such form from the beds’ flexure.

Phenomena indicating action subsequent to the beginning, and tending to change the globe’s surface . [52] Even the most solid of the globe’s layers are interrupted by fissures of varying width, from a half-inch up to several fathoms. They are perpendicular to the horizon in limestone, oblique and irregularly placed in quarries of sandstone or solid rock. They are found spaced rather far apart, and narrower, in soft materials and in the deepest beds; but more frequent and wider in compact materials, such as marble or other hard rocks and in primary beds. Often they descend down to the base from the tops of masses; other times they penetrate as far as lower layers. Some proceed with diminishing width, others maintain the same width their entire extent.

It is in these cracks that metals, minerals, crystals, sulfur, and thickened juices are found. [53] In sandstones and rock of vitrifiable materials they are inwardly lined with crystals, flints, and minerals of all kinds. In quarries of marble or limestone they are filled with spar, gypsum, grit, and earthy sand. In clays, chalk, and marls one finds these fissures either empty or filled with material deposited by rainwater.

To these cracks other significant degradations can be added, as seen in the rocks and the long mountain ranges. Examples are those enormous cuts, wide openings produced by landslides or subsidences which fill plains with huge amounts of debris from mountains whose bases are lacking. [54] This debris includes sandstones scattered irregularly on the surface of the disintegrated terrain, and lengthy portions of layers overturned chaotically. Of this kind that are visible to observers are the openings found in mountain ranges and the openings of certain straits, such as Thermopylae, the Caucasus Gates, the Cordilleras, the strait of Gibraltar between mounts Calpé and Abyla, the Hellespont, the straits of Calais and of Palermo, etc. [55]

When these collapses have acted only on internal layers, or when water by itself having deeply worked the rock removes sands and other materials of weak consistency from the mountain interior, leaving behind recesses made of rock and stony walls, what results from all these degradations are caverns. Here in these subterranean conduits is where certain rivers disappear, such as the Niger, Euphrates, and the Rhone. Here in these caverns formed within mountains there are reservoirs of abundant springs. When the roofing of these caverns collapses and fills them in, the waters they contain are pushed out and produce sudden and unforeseen floods.

Rainwater also produces big changes on the external surface. By its daily work, mountains are lowered in altitude, and plains fill in. Mountain summits are stripped of soil, and only peaks remain. Earth carried off to the plains by torrents and rivers has formed extraordinary layers of gravel and sand there. Great quantities of these are found along rivers and in the valleys they pass through. These layers have this particularity, that they show breaks; there is no parallelism in them, nor constancy in thickness. In inspecting the heaps of gravel one sees that these have been washed, rounded, and deposited irregularly in the moving water, etc. Among these sands and gravels are found, without order, without regular disposition, fluvial shells, broken and isolated marine shells, stony debris, hard stones, rounded chalks, bones of terrestrial animals, iron tools, pieces of wood, leaves, impressions of scum [ mousse ]. And the different parts of this assemblage are sometimes bound together with a natural cement produced by the decomposition of some of the gravels.

In the vicinity of ponds, lakes, and seas, alongside rivers, or near torrents, low and swampy places exist whose bottoms consist of plant matter soaked with tar [ bitume ]. Here entire trees are knocked down, all in one direction. Some layers of hardened mud are molded around the marshy reeds they have covered. Often the plant layers—the plants sometimes conserved, sometimes tracing imprints in the stone or in the hardened earth—are covered by heaps of material forming a thickness of fifty, sixty, one hundred feet. These additions, these accumulations of earth are substantial, especially at the feet of high terrain or of mountains, and appear to be built-up masses stretching toward the highest mountains.

Degradations produced by water are also seen on the seashore. At the mouths of rivers we see islands, heaps of sand, or deposits of earth which river waters pick up and carry along, and which they deposit as their flow is slowed down. Some observers have maintained that certain rivers convey earth as a burden up to one third, which is exaggerated. But it suffices to have this cause considered, even with all the moderation one may judge appropriate, so as to recognize the extent of its effects. Some coasts are worn away by sea waves, while wave action covers others with sand. The sea retreats from certain coasts, but makes incursions on others, either bit by bit or by local and intense flooding.

Another pervasive element [ principe ] of destruction is fire. Certain mountains burn continually. They undergo repeated violent attacks, eruptions in which they cast afar vortices of flames, smoke, cinders, and calcined stones. And in the furor of their burning, sulfur and fused minerals emerge through the mountain flanks opened up by the expansion of vapors that redouble the fire’s violence. I locate all volcanoes in high mountains. Their hearth is shallow, while their mouth is at the summit and within the plane of the horizon. [56] Some volcanoes are extinct, and they are recognized as such by the huge precipices some mountains show at their summits, which are like truncated cones, and by the lavas or calcined materials dispersed on their flanks. [57]

The sea bottom is not exempt from these violent agitations. Among these volcanoes in mountains are some whose top is below the level of the waves. They are seen near islands of which they are continuations and appendages. These submarine volcanoes sometimes lift up enormous masses of land that rise up above the waves, and then count among the islands. Or sometimes these burning materials, in the absence of restraining overlying masses, raise the sea surface, and form huge jets, waterspouts [ typhons ] or dreadful vortices [ trombes affreuses ]. Then the sea is in a boil, covered with calcined light stones floating on the surface over a wide area, and the air is full of sulfurous vapors [ exhalaisons ].

These effects are all ordinarily accompanied by earthquakes , a phenomenon which spreads desolation and fright far and wide. Two kinds of earthquake can be distinguished: local earthquakes, and pervasive ones. Local quakes are circumscribed in their shock, extending in all directions around a volcano or its hearth. The others follow certain belts of ground, [58] especially those along which mountains are distributed, or those made of solid materials. These extend to far greater distances than they do in breadth. These disastrous convulsions manifest themselves in different motions. Some occur by an upheaval from top to bottom, [59] others by a tilting such as would occur in an inclined plane fixed on the lower side while being lifted on the higher. Finally, others occur in a rocking motion carrying shaken objects in different directions, with marked repetitions. These various agitations can result in deadly shocks, erratic and sudden, with calamitous consequences; or they can involve calm vibrations that simply rock things without destruction. Among the effects of earthquakes may be listed the collapse and caving in of certain mountains, as well as their fissures, precipices, and chasms [ abysmes ].

Earthquake shocks, propagated by mountains and the ranges that branch out along the sea floor, are felt by navigators, and produce through reverberation severe concussions affecting vessels on the calm, smooth sea surface. Often the sea overflows the land, when the coasts have undergone violent upheavals. In short the sea coasts seem more exposed to earthquakes than the continental centers. [60]

Phenomena depending on the atmosphere and the aspect of the Sun . In this department we are given many facts and few general results. What remains to be discussed here can be reduced to three points. The first involves consideration of the varied temperatures prevailing in different parts of the globe. The second concerns agitations of the atmosphere, and their effects. The third has to do with the circulation and modification of vapors and exhalations that float in the atmosphere.

The temperature occurring in different parts of the earth can be imagined quite straightforwardly through zones defined by degrees of latitude. However, what must also be taken into consideration are the terrain, the varying length of time the Sun is above the horizon, and winds. All these factors do much to modify the effect of the varying angle of the Sun’s rays in different lands.

The gap occurring between the extremes of greatest heat and greatest cold in each country increases in proportion as one moves away from the equator, with some exceptions as ever dependent on the Sun, and especially on the proximity of the sea. A land that is inhabited, cultivated, and arid is less cold. A maritime land is less cold at a like latitude, and possibly also less hot.

In proportion as one rises above the lowlands in high mountains, heat diminishes and actual cold begins to be felt. In the mountains of the Cordilleras, the snow covering some summits does not melt above a height of 2440 fathoms above sea level, and heat respects this limit through the entire length of the Cordillera. In temperate zones, mountainous country also has snow-covered summits, and even monstrous heaps of ice that summer heat does not entirely melt. Only the line marking the boundary of snow that never melts is lower in these zones than in the torrid zone.

But cold never spreads into the plains in the torrid zones, in the way it makes its effects felt through the breadth of the temperate and frigid zones. Rivers freeze on the continental surface, as do lakes in parts of the temperate and the whole of the frigid zones. But salinity prevents this in the open seas at those latitudes. It is only toward the coasts, in tranquil localities, in gulfs or straits of the frigid zones, that the sea freezes. And this ice does not extend beyond around twenty leagues from the coasts. The sea freezes especially in places where rivers empty large quantities of fresh water, or transport great chunks of ice which accumulate in the mouth, and contribute to the formation of those enormous icebergs which subsequently journey into seas to the south. In this fashion ice found in the open seas is a sign of large rivers having their mouths near those waters. As for temperatures underground and at different depths of the sea, we can provide no well-ascertained results.

The main disturbances in the air which we take into account are the winds. Generally speaking, the flow of air is very irregular and highly variable. Nonetheless winds from the east blow continually in the same direction as a consequence of the rarefaction the Sun produces successively in different parts of the atmosphere. As the stream of air resulting from this expansion must follow the Sun, it produces a steady wind generally from east to west, the action of which contributes to the general motion of the sea from east to west, and which prevails as far as 25 or 30 degrees on each side of the equator.

Polar winds also blow quite steadily in the frigid zones. In temperate zones there is no known uniformity. The movement of the air is a composite of the winds prevailing in neighboring zones, which is to say easterly and northerly winds. To how many modifications must these air currents be subject, in order for the easterlies or the northerlies to dominate? Indeed, the west wind seems to be a counter-flow of the easterly modified by shoreline features.

At sea or along the coasts, winds are steadier than over land. They also blow with greater force and continuity. On the continents, mountains and forests and different landforms alter and distort the direction of winds. Winds reflected off mountains affect neighboring provinces. These are quite irregular because their direction depends on that of the original current that produces them, as well as on the shapes and location of the mountains, and even the gaps between them. That is to say, land winds blow intermittently and by fits and starts.

In spring and autumn winds are stronger than in winter and summer, both at sea and over land. They are also more intense in proportion to elevation above the lowlands even as far as above the region of clouds.

There are periodic winds which are constrained in certain seasons, on certain days, at certain hours, and in certain locations. Some of these are governed by snow melt, and by the tides. Sometimes winds blow from land during the night, and from the sea in daytime. We don’t have enough observations yet to know whether there is some connection among the vicissitudes in the air in each place. We only know from barometric observations that there are more variations in the temperate zones than in the torrid and frigid zones, and that variations are fewer in the upper part of the atmosphere than in the lower part where we live.

Air, having attained a certain temperature by virtue of solar heat, dissolves water and becomes loaded with it. This is the result of that copious evaporation of water from the surfaces of sea and land. Once these vapors are condensed they make clouds which the winds circulate within a certain region of the air, depending on the densities of both clouds and air. They are transported to all climes. Clouds carried this way either rise as they expand, or descend as they condense, in accord with the temperature of the lower atmosphere that supports them. In their passage when they meet colder mountain air, either they precipitate there as snowflakes, fog, or dew, depending on their density and elevation; or they coalesce and settle as rain. The east wind disperses clouds particularly between the tropics. This causes both the abundant rains of the torrid zone and the periodic floods of rivers taking their sources in those countries.

Sometimes clouds condensed on mountain tops are carried away by reflected winds, or by other winds dispersing them in neighboring plains.

Mountains contribute so much to this distribution of water that a single mountain range can determine summer and winter within both parts of a peninsula it traverses. It is understood as well that as the character of the land contributes to the atmosphere’s condition, there will be countries where no rain will fall, because the clouds rise over those places as they expand.

In a word we see now why we have recognized certain drainage divides for distribution of water flowing over the continental surface. These drainage points are high localities, bristling with mountains and peaks which take hold of clouds, attract and condense and settle them as rain, etc.

When contrary winds blow against a certain mass of condensed clouds which are ready to settle as rain, they produce in effect continuous cylindrical streams of water, that fall straight down from the clouds to the surface of sea or land. The winds give water this cylindrical form by confining and compressing it through opposing actions. These cylinders are called whirlwinds [ trombes ], which must not be confused with the waterspout [ typhon ] or sea funnel [trombe de mer ]. Such effects can be related to those produced by severe and contrary winds when they lift vortices of sand and earth and envelop houses, trees, and animals.

Such is the general idea of the objects with which Physical geography is concerned, which will be developed in separate articles. It is easy to see from this presentation, that a system of Physical geography is simply a methodical framework for presenting proven and fixed facts and for bringing them together so as to draw general results from their combination: general operations over which rules a wisdom and good faith that permit a glimpse of the gaps where the chain’s continuity is broken, that is not so satisfied with observations already made as not to show the need of new facts and the means of acquiring them. In the theories of the earth other designs are pursued: all facts, all observations are brought to bear on certain basic agents, to reach back and break away from the present and well-examined state to a state which came before; in a word from effects to causes. The aim of theories of the earth is great and lofty and provokes further curiosity. But they should only be general consequences of a thorough scheme of Physical geography . [61]

1. Notwithstanding the restriction stated in this definition, Desmarest’s article is not devoid of considerations relevant to the earth’s habitability or fecundity. For example, there is extensive discussion of the distribution of fresh water, and of evidence (huge deposits of marine fossils) of accumulated debris of animal life.

2. As with so many other terms whose meanings have undergone significant adjustments since the mid-18 ^th century, Physique must be understood as something rather different from modern physics, although of course there are important historical connections. As d’Alembert would explain in his article Physique, this was essentially the same as Natural Philosophy, the broad enterprise aimed at understanding the properties and phenomena of all natural objects (not excluding living things).

3. In elaborating on the theme of discovering order behind the immediate appearance of disorganization and destruction, Desmarest borrowed both ideas and phraseology from Buffon, Histoire et Théorie de la Terre (1749), in the opening volume of Histoire Naturelle, générale et particulière, p. 69 [p. 98 in this edition], where it is said that an observer of features at the earth’s surface or in its accessible subterranean parts sees a variety of irregular, disorderly things, “toutes mêlées & dans une espèce de confusion qui ne nous présente d’autre image que celle d’un amas de débris & d’un monde en ruine.” Desmarest appropriated practically the same words: “... qui ne nous avoit présenté d’autre image que celle d’un amas de débris & d’un monde en ruine.” This terminology was later taken up by others as well—for example, by d’Holbach in his Systême de la Nature (1770), pt. 2, p. 8, where he stated that observation of our globe “ne nous montre part-tout qu’un vaste amas de débris & de ruines.”

4. As one judges without difficulty in reading through this article, the term rapport —which arises dozens times in its 13 pages—has a place of special importance in Desmarest’s conception of his subject. How to translate this term is mildly problematic: no single English word is right for all instances. That rapport is sometimes used without translation in modern English-language discourse is proof enough that no single English word is quite equivalent. Depending on context, it is variously translated here as relation or relationship , but also on occasion as connection , or affinity . In certain circumstances a valid translation might also be correlation . From the text one infers that Desmarest’s idea of rapport in physical geography normally involves visible linkages or observable interconnections between specific geographical or topographical features. In mathematics, rapport means ratio . While Desmarest’s conception of physical geography was not overtly mathematical, it is by no means impossible that his sense of rapports obtaining in the relationships exhibited by objects in this domain was informed by something of the abstract character of a mathematical ratio. In fact, his principal example had a geometric quality: the so-called correspondence of angles, or of topographic entrants and re-entrants. He evidently held that, at the outset of inquiry, the nature or underpinning of such relationships is usually obscure. Indeed, in his view the basic point of attempting to discern or discover such relations is the anticipation that further study and analysis may lead to some kind of understanding (optimally, causal understanding) which will furnish the investigator with insights into the natural processes responsible for the phenomena of physical geography. Thus the quest for meaningful rapports constituted the primary research pathway, or investigatory strategy, by which Desmarest believed knowledge in the field of physical geography could be advanced. See Kenneth L. Taylor,” Natural Law in Eighteenth-Century Geology: The Case of Louis Bourguet,” XIIIth International Congress of the History of Science, Proceedings 8 (1974): 72‒80; Taylor, “Les Lois naturelles dans la géologie du XVIIIème siècle: Recherches préliminaires,” Travaux du Comité Français d’Histoire de la Géologie , 3ème série, 2 (1988): 1‒28; Taylor, “Two Ways of Imagining the Earth at the Close of the 18 ^th Century: Descriptive and Theoretical Traditions in Early Geology,” in Abraham Gottlob Werner and the Foundation of the Geological Sciences: Selected Papers of the International Werner Symposium in Freiberg 19th to 24th September 1999 , Freiberger Forschungshefte, D207, ed. H. Albrecht and R. Ladwig (Freiberg: Technische Universität Bergakademie Freiberg, 2002), 369‒378; Marguerite Carozzi, “From the Concept of Salient and Reentrant Angles by Louis Bourguet to Nicolas Desmarest → ’s Description of Meandering Rivers,” Archives des Sciences 39 (1986): 25‒51; Isabelle Laboulais-Lesage, « Voir, combiner et décrire: La géographie physique selon Nicolas Desmarest → ,” Revue d’histoire moderne et contemporaine 51 (2004): 38‒57.

5. The multivalent term expérience is translated here as experiment , since Desmarest’s phraseology suggests a distinction between the relatively detached process of observation and the more actively interventionist or artificial performance of experimenting.

6. The primary meaning of histoire , a word of ambiguous quality in its early modern usage, corresponded to description ; it usually denoted compiled information, assemblages of facts (as seen in continuing modern acceptation in natural history ). Only secondarily did histoire refer to a notion of an account related through a sequence of events. See Rhoda Rappaport, “The Earth Sciences,” in The Cambridge History of Science , vol. 4: Eighteenth-Century Science , ed. Roy Porter (Cambridge: Cambridge University Press, 2003), 417‒435.

7. Although there did not yet exist a recognized geological branch of natural science (evidence that this was happening became apparent during the century’s closing decades), certain general ideas on how to understand the earth’s organization were much discussed during the 18 ^th century. One of these, emerging around mid-century, was a conventional distinction between two main categories of rock structures visible at the globe’s surface: a primary (sometimes called primitive ) group of rocks characterized by their massive and largely undifferentiated forms, generally containing no discernible organic fossil bodies (granites and schists were typical kinds of primary rocks), and a secondary group typified by stratified beds frequently bearing fossil objects. Gabriel Gohau, A History of Geology , trans. Albert V. Carozzi and Marguerite Carozzi (New Brunswick, NJ: Rutgers University Press, 1990), 79-81; Gohau, Les sciences de la Terre aux XVIIe et XVIIIe siècles. Naissance de la géologie (Paris : Albin Michel, 1990), 174‒176.

8. In this section Desmarest may be seen as expressing views on a kind of observation that was not yet clearly distinguished with a name of its own—what would later come to be known as fieldwork or field observation ( travail de terrain ; observation [or enquête ] du [or sur le ] terrain ; observation sur les lieux ). See Martin J. S. Rudwick, “Minerals, Strata and Fossils,” in Cultures of Natural History , ed. N. Jardine, J. A. Secord, and E. C. Spary (Cambridge: Cambridge University Press, 1996), 266‒286; Rudwick, Bursting the Limits of Time: The Reconstruction of Geohistory in the Age of Revolution (Chicago: University of Chicago Press, 2005), 73‒75; Laboulais-Lesage, “Voir, combiner et décrire.” Desmarest’s stout profession of commitment to direct observation as the correct path toward progress in physical geography should not be taken as evidence that he was personally engaged in field observation at the time he wrote this article. In fact, the substance of the article’s second part—a recitation of what he considered significant facts of physical geography—was based on Desmarest’s knowledge of relevant literature. It was only at about the time that this article was published, in the late 1750s, that he began the process of learning to make his own field investigations. See Kenneth L. Taylor, “The Beginnings of a Geological Naturalist: Desmarest, the Printed Word, and Nature,” Earth Sciences History , 20 (2001): 44–61.

9. Desmarest’s frequent use of the term circonstance (in both singular and plural forms) poses another problem in translation. Rendered here as feature , in other instances (more than a dozen throughout the article) it is variously translated as condition , consideration , circumstance , possibility , or factor .

10. Vûes , another word frequently used in Desmarest’s article, is translated in different ways in varying situations. In addition to perspectives , as chosen here, in some other circumstances the translation selected is preconceptions , insights , views , ideas , notions , or designs ; and on occasion (for the singular form) the words sight , vision , and standpoint serve.

11. As printed originally, this sentence ended with a question mark. This was evidently a printing error. We may be confident this was the case, since Desmarest later republished this entire Encyclopédie article, with embellishments, in his Géographie Physique in the Encyclopédie Méthodique series — and this sentence appears there without the question mark. (Desmarest, Encyclopédie Méthodique : Géographie Physique , vol. 1 (Paris: H. Agasse, 1794), p. 795.

12. Fente perpendiculaire could also be translated as vertical joint . However, since the term joint came eventually to have a specific geological meaning (set within a particular framework of petrological theory not yet fully formulated in Desmarest’s time) which may not correspond fully and precisely to the phenomenon described in this article, perpendicular crack is selected instead (or fissure , as appears in a later portion of the article). Desmarest evidently thought that by taking note of discernible regularities in such cracks one might gain insight into the processes by which rocks were formed or altered.

13. It was understood (on the authority of chemists dating back to J. J. Becher in the previous century) that in general, whereas calcareous materials (limestones) undergo chemical alteration when subjected to heat, vitrifiable rocks when heated are susceptible to change of physical form, alteration into a glassy state.

14. Desmarest’s comments on trapezoidal forms taken by certain rocks, and on geometric forms observed in crystallizations, reflect a set of interests commonly expressed in the 18 ^th -century literature of mineralogical natural history. In Desmarest’s case, this interest is similar to his concern to note patterns in rock cracks or fissures, as mentioned in note 11. He would later expand on these concerns in a number of the articles he would prepare for the volumes on physical geography in the Encyclopédie méthodique series (for example, articles on Ardoise , Argile , Cévennes , Circulation des eaux , Dessication , Fentes , Ligurie ). See ← Nicolas Desmarest → , Géographie physique, volumes 93-97 of Encyclopédie méhodique (Paris: H. Agasse, 1794-1828). Prior to writing “Physical geography” for the Encyclopédie , he had manifested some interest in this sort of issue in the editorial commentary he added to the French translation of Francis Hauksbee’s Physico-Mechanical Experiments , specifically in a mention of J.-J. Dortous de Mairan’s idea ( Dissertation sur la glace , 1716, 1749) that molecular parts organize themselves in certain angular forms. See Desmarest, ed., Experiences physico-mechaniques sur différents sujets, (Paris, 1754), 2: 94‒95.

15. Buffon quotation adapted from John Lyon’s translation of “Initial Discourse: On the Manner of Studying and Expounding Natural History,” in John Lyon and Phillip R. Sloan, From Natural History to the History of Nature: Readings from Buffon and His Critics (University of Notre Dame Press, 1981), 98. In this passage, Buffon was of course speaking generally about natural-history study, not specifically about physical geography.

16. Absorbing whirlpools ( gouffres absorbants ) were distinguished from expelling ones ( gouffres vomissants ). See Desmarest’s article Fontaine.

17. Athanasius Kircher (1602‒1680), polymathic German Jesuit scholar. His Mundus Subterraneus (Amsterdam, 1665) was a widely known work, but little trusted by naturalists of the mid-18 ^th century. A prolific author of broad learning, Kircher was by then seen by many as uncritical and credulous.

18. See note 5 above. Desmarest’s use of the word expérience in this paragraph suggests a notion of experiment in the sense of systematic organization of strategically collected data, more than performance of controlled manipulations of the natural phenomena in question.

19. Père Feuillée: Louis Éconches Feuillée (1660‒1732), a Minim explorer, geographer, astronomer, and botanist, known in particular for his journeys in the West Indies and South America; author of Journal des observations physiques, mathématiques et botaniques (Paris, 1714‒1725).

20. Louis Bourguet (1678‒1742). His conception of the significance of “corresponding angles” or “salient and re-entrant angles” was expressed in his “Mémoire sur la Théorie de la Terre” at the end of his Lettres philosophiques sur la formation des sels et des crystaux (Amsterdam, 1729). See Taylor, “Natural Law in Eighteenth-Century Geology;” Carozzi, “From the Concept of Salient and Reentrant Angles;” François Ellenberger, Histoire de la géologie , vol.2: La grande éclosion et ses prémices, 1660‒1810 (Paris: Tec & Doc, 1994), 60‒62.

21. The key terms of the expression on arrange même dans des partitions inexactes are here rendered incorrect arrangements , on the basis of the contemporary musical associations of the word partition (as referring to a musical score, to the ensemble of a composition’s parts).

22. The expression petite méprise , which might more literally be translated as small mistake , is rendered here as minor artifice , on grounds of the words’ undertone of travesty or derisive mockery.

23. Desmarest’s interest in the kinds of organization seen in the distribution of land and sea over the globe was informed by study of the Geographia Generalis of Bernardus Varenius (1622‒1650). [See A Compleat System of General Geography (London, 1734) for a translation.] This is suggested in particular by his mention of the idea of Mediterranean embayments dividing the continental land masses, a notion he probably derived from Varenius. While Varenius is not mentioned by name in this article, it is known that Desmarest had by this time undertaken study of this geographical authority. See multiple references in Desmarest, Dissertation sur l’ancienne jonction de l’Angleterre à la France, qui a remporté le prix, au jugement de l’Académie des Sciences, Belles-Lettres & Arts d’Amiens, en l’année 1751 (Amiens, 1753) and Expériences physico-méchaniques .

24. Bab-el-Mandeb; connecting the Red Sea to the Gulf of Aden.

25. This paragraph summarizes contentions highlighted in Buffon’s Théorie de la Terre (1749), and illustrated in that work by maps.

26. No reference is given. But Bacon’s remarks may be found in Novum Organum, Book II, Aphorism XXVII.

27. Mount Imaüs : Geographical tradition dating back to the Hellenistic period identified this as a great mountain, or group of mountains, of central Asia.

28. Collateral branches is the rendering here for adossemens collatéraux . In other instances below, adossement or adossemens is translated as assemblage(s) or mass(es) . The verb form adosser or adossé is translated as back up or backed up against .

29. See note 20 above.

30. Throughout his discussion of mountains Desmarest invokes a conception of a global mountain framework, or charpente du globe , associated principally with the Royal Geographer Philippe Buache (1770‒1773). Although Buache is not mentioned by name in the article, Desmarest’s affinity with his ideas was made clear in Desmarest, Dissertation sur l’ancienne jonction de l’Angleterre à la France .

31. In his first conspicuous publication, Dissertation sur l’ancienne jonction de l’Angleterre à la France , Desmarest argued that an isthmus formerly connecting England and France had been broken at some point in the remote past.

32. Pas de Calais refers to the narrowest part of the strait between France and England. What in English is usually called the English Channel is La Manche (or le Canal de La Manche ). The two basins referred to (on either side of the Calais Strait) are La Manche and the Mer du Nord .

33. It may be noteworthy that the word Océan (always capitalized) appears in this article just four times, all within a few paragraphs after this first instance. The word mer , by contrast, occurs 102 times.

34. It was common in scientific writing during the 18 ^th century to refer to the general phenomenon of sea movements affected by lunar motion as the flux et reflux de la mer . The distinction (quite loose) between this phenomenon and the tides ( les marées ) perhaps reflected a sense of demarcation between a general cause and its local effects.

35. Dividing points : The idea of divides separating drainage basins ( points de partage , or partages des eaux ) was an important organizing principle among French geographers during the 18 ^th century. Physical maps from the period (notably, those by Buache) tend to emphasize patterns in the continental distribution of water. The terms in question may also be rendered as drainage basin divides . The singular partage could be translated simply as divide .

36. The notion of intervening areas left empty seems rather obscure.

37. La Mer du Sud is the Pacific Ocean.

38. Plaines montueuses . Note earlier reference to plaines en montagnes , at the close of the 25th paragraph prior to this one. Thus invoking, apparently, a generalized concept of plain-like uplands in mountainous regions.

39. Here, as elsewhere (see note 3 above) Desmarest’s phrasing echoes that found in Buffon’s 1749 Théorie de la Terre . See Taylor, “La Genèse d’un Naturaliste.” The recurring terms lit , couche , banc are variously translated here usually as bed and layer . Stratum or strata are avoided in this translation, as the word strate does not appear in the article.

40. One ligne or line = one-twelfth of a French inch ( pouce ).

41. This sentence is obscure.

42. The meaning of montagnes figurées seems obscure. Sharply delineated? Distinctively shaped?

43. The idea that there exists a correlation between internal rock structures and surface topography was frequently discussed, and not seldom disputed, in the literature of earth science during the 18 ^th century.

44. See note 13 above.

45. Assises is translated here as measures , in light of the term’s usage in mining.

46. A notion widely discussed (and often refuted) during the 18 ^th century held that the strata of the earth’s crust ought to be ordered such that their specific gravities or densities increased with depth. The idea can be traced to John Woodward’s Essay Toward a Natural History of the Earth (1695). It was a topic Desmarest had addressed in his edition of Hauksbee’s Physico-Mechanical Experiments .

47. Roc vif , translated here as solid rock , appears to correspond generally to what modern-day geologists call bedrock , i.e., the solid rock underlying superficial soil and other weathered or broken material (this overlying unconsolidated material being called, in modern terms, regolith ). Marnes , translated here as marls , may also be rendered as chalk or clay .

48. Caillou : this word may mean pebble ; in certain contexts it may refer also to flint or flintstone . During the second half of the 18 ^th century one finds in the literature of mineral natural history frequent expressions of interest in the significance of cailloux roulés —rolled or rounded stones—commonly understood to have acquired their rounded shape from sustained rolling in moving water.

49. The term fossil was still generally used, during the middle part of the 18 ^th century, in application to any object found in the earth, regardless of its derivation. Thus this broad class of objects could include a great variety of things, including crystals, coal, and stalactites, as well as bodies with the shapes of parts of animals or plants. (Also included were buried objects we would call human artifacts, such as axe-heads or shards.) By the middle of the 18 ^th century a consensus had been achieved, among people of learning, that fossil bodies resembling shells or animal bones or plant impressions generally were, in fact, derived from once living things, rejecting alternative theories that attributed such objects to generative powers within the earth. See Martin J. S. Rudwick, Th e Meaning of Fossils: Episodes in the History of Palaeontology (London: Macdonald; New York: American Elsevier, 1972). In this article Desmarest’s discussion of fossils is basically confined to what by this time had become customarily thought of as extraneous or extrinsic fossils (objects whose derivation lay elsewhere, but had come to be enveloped in rock or soil). These were generally distinguished from intrinsic fossil bodies—those taken to have developed within the ground or the rock. Amplifying on this distinction, what Desmarest presumably meant by a plain or natural fossil ( en nature ) was an extraneous body not (yet) transformed in its substantive components (e.g., a bone, tooth, or plant material), whereas a petrification displayed partial or complete transformation into mineral or stony material (a process Desmarest would have understood as involving gradual replacement of original material by a process of mineralization).

50. Desmarest refers here to the famous falun of Touraine, best known among contemporary naturalists through the 1720 memoir by René A. F. de Réaumur in the Mémoires de l’Académie Royale des Sciences de Paris (“Remarques sur les coquilles fossiles de quelques cantons de la Touraine, & sur les utilités qu’on en tire”).

51. This reference to an excavation at Amsterdam evidently connects with a passage in Varenius’s Geographia Generalis (Chap. VII, Prop. VII), discussing what was discovered in the ground when a well was dug to a depth of 232 feet; commented upon also by Buffon in his Théorie de la Terre (1749, p. 245).

52. The title of this sub-section, indicating a focus on geographic transformations (involving mainly degradations by gravity, water and fire), relates to the question he had taken up in the prize-essay contest that gained him recognition in the learned world just a few years earlier: rupture of an isthmus formerly connecting England with France. Yet within the broader framework of this article, such transformations receive rather modest emphasis. He appears to have thought at this time that attention directed at processes of change was less important, for the investigative physical geographer, than examination of static relationships among discernible topographic features. There is little in this article to presage Desmarest’s pursuit, during the 1760s and 1770s, of evidence of vast erosional changes in Auvergne landforms, which he would interpret in terms of distinct epochs, or a kind of geological periodization. See Kenneth L. Taylor, “Desmarest’s ‘Determination of some epochs of nature through volcanic products’ (1775/1779),” Episodes: Journal of International Geoscience 32 (2009): 114–124; also Rudwick, Bursting the Limits of Time , esp. 203‒212.

53. Suc epaissis presumably relates to contemporary ideas about mineral generation out of the action of fluids or juices within the rocks ( succus lapidificus or succus lapidescens ). See Frank Dawson Adams, The Birth and Development of the Geological Sciences (1938), Chap. 4 on the generation of stones, section “The Theory of the Lapidifying Juice,” 90‒94. Adams attributes the concept mainly to Agricola. One finds expression of the idea in Abrégé de la Philosophie de Gassendi (Lyon, 1684), Livre I, « Des Choses Terrestres, » chap. 5, pp 70 ff: « Des Sucs ou Mineraux qui sont renfermez dans le Globe de la Terre. »

54. This reference to mountains lacking bases ( montagnes dont les bases manquent ) is unclear.

55. Les portes du Caucase or Caucasian Gates evidently refers to the Darial Gorge or Pass of Darial (or Dariel), on the borders of Russia and Georgia. Mons Calpe was the Roman name of Gibraltar; Mons Abyla lay across the strait on the African side (thus Mons Calpe and Mons Abyla were the two Pillars of Hercules). What was meant by the Portes des Cordelieres is unclear.

56. Foyer is translated as hearth . It could alternatively be seat , or focus . Speaking of the mouth (or crater) as dans le plan de l’horison presumably means that the plane of the opening is parallel to the horizon (rather than congruent with it).

57. Desmarest’s conceptions about volcanoes, as expressed in this article, are in accord with those widely accepted at the time. It was conventional to see a volcanic eruption as something that occurs within certain mountains; that is, it was not commonly believed that volcanoes represent mountains generated by the eruptions they displayed. Volcanic action was considered, in the larger scheme of things, a superficial phenomenon, taking place not far from the surface; it was a phenomenon in which pre-existing materials are altered by heat, which might be generated by one of several sorts of exhaustible processes (such as combustion of subterranean coal, or fermentation of certain sorts of minerals). Volcanic processes were generally thought of as destructive, not generative. (See Kenneth L. Taylor, “Before Volcanoes Became Ordinary,” in History of Geoscience: Celebrating 50 Years of INHIGEO , ed. Wolf Mayer, et al . (London: Geological Society of London Special Publication 442, 2017), 117‒126. During the 1760s Desmarest would establish himself as a naturalist with special knowledge of volcanoes, based on investigations especially of extinct volcanic terrain (in Auvergne, and in Italy) but also of one active volcano: Vesuvius. However, at the time he composed this article Desmarest’s knowledge of volcanic phenomena was based exclusively on reading, possibly supplemented by personal information provided by others more well-travelled than he was at the time. See Taylor, “La Genèse d’un Naturaliste.” Desmarest’s researches during the 1760s and 1770s led to his acceptance of a broader role for volcanic action in forming terrain, but to the end of his life his basic ideas about the operations of volcanoes underwent remarkably little change.

58. Bande is translated here as belt ; one could also use the term strip . Terrein is translated as ground , although it could also be land , rock , or terrain . It may be useful to know that the mineralogical naturalist Jean-Étienne Guettard (1715‒1786) had lately used the term bande in arguing that distinguishable types of surface rocks could be traced in bandes (or surface areas displaying certain distinctive mineralogical characteristics) crossing the Manche, thus appearing on both sides of the Channel. Guettard pioneered mapping these sorts of correlations.

59. This is puzzling: un soulevement de haut en bas (an uplift or upheaval, from top to bottom, or downward) seems contradictory.

60. As part of the torrent of earthquake literature provoked by the disastrous Lisbon quake of 1755, Desmarest had published a pamphlet offering a suggested mechanism by which earthquake shocks are transmitted: Desmarest, Conjectures physico-mécaniques sur la propagation des secousses dans les tremblemens de terre, et sur la disposition des lieux qui en ont ressenti les effets (Paris, 1756). His argument focused on passage of shocks over great distances through the networks of mountain chains championed by Buache.

61. Desmarest’s demarcation in this article of the enterprise of physical geography from that of the Theories of the Earth was a position he continued to hold throughout his lifetime. It should not be overlooked, however, that Desmarest did not reject the legitimacy of efforts to construct a satisfactory Theory of the Earth; indeed, he states in the article’s closing sentence that the way to build such a Theory is through disciplined pursuit of observationally-based study in physical geography. This point is historically significant, on account of a tendency among some historical commentators toward classification of empirical-minded investigators like Desmarest as belonging in a category opposed to theory-construction (e.g., Hermann Rudolf Weber, Die morphologischen Anschauungen von Nikolas Desmarest. Ein Beitrag zur Geschichte der Morphologie im 18. Jahrhundert (Doctoral dissertation, University of Leipzig, 1932). It should be evident that Desmarest’s article as a whole is directed toward cautious and deliberate development of generalizations—in short, he held that sound theory constitutes the goal toward which physical geographers should strive. Too much emphasis on differences between authors of geo-theories and observation-minded thinkers like Desmarest, which tempts some to see these as two antithetical groups, risks obscuring the ways the empirically-grounded researchers like Desmarest were not only committed to goals similar to those of the theorists, but were also inspired by ideas found in extant theories in their efforts to identify promising types of describable phenomena as stepping-stones toward a viable theory.