Smithsonian Report/1898/Oceanography
OCEANOGRAPHY.[1]
By M. J. Thoulet.
A new science has lately made its appearance and is beginning to be recognized. To be exact, it is not absolutely new; it is nearly two centuries old in its well defined aim, its methods of investigation, its known laws, the indication of possible discoveries which remain to be accomplished; in a word, in its individuality as a didactic science, but until very lately it was the object of individual research only, and as it was studied but by a few specialists it remained almost unknown to the public.
This science is oceanography. Its purpose is to ascertain the phenomena which are going on in the depths of that immense mass of water which covers more than three fourths of our globe, to consider them, explain them, discover and formulate the laws that govern them on the surface and at the bottom of those abysses which were once supposed to be unfathomable at the time when people believed in the unfathomable. To-day oceanography is progressing with giant strides. All maritime nations contribute to its development, no less from the theoretical point of view,, for its great benefit to the human mind, whose right and duty it is to seek to know all things, than from the practical point of view of the material advantages to be derived from it; for the contest between man and nature, growing always more severe, makes it imperative that no force be left unproductive. France established oceanography. She made important discoveries and then stopping, left the care of continuing the work to others, forgetting even those of her children whose attainments, unnoticed by her, were elsewhere seized upon and utilized. Now that foreigners have made an advance which it is impossible to ignore, she seems to be aroused to a regret for the time and territory lost. She is certainly in a position to promptly regain both if she desires it.
We intend to explain of what oceanography consists, to show its direct relation with other sciences, its theoretical and practical utility; we shall give a short history of its progress from its beginning until the time when it became a complete whole; a clear and systematic exposition of facts carefully considered and elucidated. We shall say a few words concerning what has been done in this line of thought by different nations, with the character which their peculiar temperament, the conditions of their past and of their present have given to their work. In fact, just as the acts of each man, physical as well as moral, are marked with the special imprint of his personality so in the domain of science every race stamps its work, the product of its collective intelligence, with an impress peculiar to it, which constitutes the very essence of its genius.
I.
Oceanography is the study of the sea. Static oceanography deals with salt water considered independently of the movements which are manifested in it; it treats successively of the topography of the ocean beds and of their formation, their lithology. It analyzes the waters, their composition and their influence on the nature of the depths, their numerous physical properties, the effect on them caused by changes of temperature, their density, their compressibility, the way in which light is diffused throughout the superposed strata, and the different optical phenomena. The ice of the polar region offers subject matter for a chapter on the effect of cold on the sea.
In dynamic oceanography the ocean is studied in motion. We study the waves, which move the surface under the influence of the wind, and the currents, which, like the network of our arteries and veins, traverse its mass to a certain depth, and result from the simultaneous actions of heat, evaporation, the topography of the sea bottom, the geographic configuration of the surrounding continents, the climate, the force of the winds; in a word, from the total of exterior causes which, whatever they may be, all exert some influence and in turn are influenced—a constantly recurring cycle of change whose cessation would bring instant death to our planet as the last beat of the human heart terminates the life of the body. Dynamic oceanography also includes the study of the tides, whose rhythmic movements accord with those of the stars, and the examination of those processes by which the débris of the continents, swept off by winds or washed away by rivers, reach the great common reservoir, are diffused throughout its waters, descend in a shower to the very lowest depths, and there accumulate to form rocks like the greater part of those which we find now on our continents and which formed the bottom of the oceans of former ages. It deals with the phenomena that result from the contact between sea and land, seeks out the laws which control the formation of deltas or of the bars which extend across the mouths of rivers, the filling up of estuaries, the way in which waves and currents shape the contours of the shores, dunes, lagoons, and those madreporic formations—atolls and coral islands—conquests of organic life over inorganic matter, of the infinitely small, the zoophyte, over the infinitely powerful, the ocean.
Oceanography has to do then, directly or indirectly, with a multitude of sciences and, more than any other, with geology. The present is at the same time the key of the past and of the future, especially in natural history. Man, in his investigations, works from the known to the unknown, from what he can see with his eyes, touch with his hands, measure with his instruments, to that of which he can perceive only the results; from phenomena present before him to those which were accomplished thousands of centuries ago. For a long time geology advanced in a rut out of which oceanography has forced it perhaps a little against its inclination. Old people and old sciences have their habits and a dislike to change, but old sciences, more fortunate than man, can grow young again.
Rocks are of igneous or metamorphic and of sedimentary origin. The former are the object of the researches of a special science, petrography, which studies their intimate nature and all the different branches of knowledge which relate to eruptive phenomena. Stratigraphy deals with rocks of aqueous formation, and, as the genesis of these is intimately connected with the order of their superposition, stratigraphists, in their investigations, consider together the constitution and the order of the sedimentary strata. Now, since these strata have been found beneath the water, nothing is more fitted to make their genesis clear than observation of the manner in which at the present time rocks are being formed on the bottom of our oceans. This task, to which it applies itself with ardor, is the duty of oceanography. When the particular character of the formations on the coasts or in the depth of the sea is known, when careful observation and exact measurement of actual phenomena shall have taught, for example, the necessary relation between the form and dimensions of a grain of sand and the exact velocity of the current which has transported it and affected its shape—angular when supported by force of the water, worn and rounded when simply rolled along the bottom among other grains; as soon as the presence, recognized quantitatively, of a fixed proportion of clay in the midst of a sandy deposit shall allow us, by means of physical and mechanical laws, to determine whether this deposit was formed in calm or agitated water; as soon as numerous measurements, repeated in different parts of the ocean, shall have established the generality of these relations—that is to say, made laws for them—we shall be ready to reconstruct the past. It will be sufficient to find the same characteristics in an old deposit to be able to call established relations to our aid. We may affirm that the point where the deposit was formed was at such and such a depth in the ocean, at such a distance from the shore. If, later, other sciences bring forward their cooperation and point out new relations, all the details will, one after another, appear. We shall then ascertain the size and form of the Silurian, the Carboniferous or the Cretaceous Sea, the force of its waves, its salinity, the temperature of its waters, the intensity and direction of its currents, its flora and its fauna. Thus, having for foundation only a single grain of sand observed beneath the microscope and which, through oceanography, shall have recounted all the events at which it has assisted, after centuries upon centuries the edifice will appear firm, solid, in its complete magnificence. Do not think that this is a scientific dream, as full of uncertainty as of charm. These deductions have the absolute and unquestionable precision of mathematics. After so many unexpected discoveries, our epoch leaves it no longer in doubt that the greatest poets are sometimes the scientists.
The laws of meteorology present an important practical interest because they lead up to the forecasting of the weather. There is no need to dwell upon the profit humanity may derive from such a discovery. How many misfortunes will be averted for the agriculturist! Navigation will feel no less benefit if it can know in advance the regions of calm, of contrary or favorable winds. How many voyages will be shortened, how many lives saved! We can judge of this from cyclones. Formerly the terror of sailors, since their laws have been known they have been utilized to expedite voyages. The subjugated hurricane works for the sailor, and when ordered to bring the ship more quickly into port the docile tempest obeys and thus averts the dangers of the route. Who among our forefathers would have dared to formulate such a dream, realized, nevertheless, through the work of Bridet? Now the laws of the aerial ocean and of the liquid ocean are the same, although more complicated for the first than for the second. They should consequently be studied synthetically on the sea and applied afterward to the atmosphere, with such modifications as are made necessary by the great difference in the mobility of the two fluids. The rational introduction to meteorology is oceanography. Steam has greatly modified and simplified the former conditions of navigation, and to-day steamers progress almost in a straight line despite wind and sea. However, the sailing vessel is not as dead as some may believe. As a result of the mutual interactions, so delicate, so changeable, of economic conditions, of the high price of coal, of the large space occupied by the machinery and the store of fuel, of the higher salary of mechanics, and for still other causes, many nations are returning to sailing vessels. Americans in particular possess clippers of great speed, which carry freight at less charges than do steamships. The study of the phenomena of the ocean has lost none of its practical utility to navigation and it has become indispensable for the elucidation of a multitude of points. Marine currents are elucidated by meteorology, because of the influence which regular winds have upon the flow of the waters. They control the course of floating ice fields. The dangers to boats off the banks of Newfoundland are well known. To this place come the icebergs which have broken off from the glaciers of Greenland, and have been carried down Baffin's Bay by the Labrador current to melt away at contact with the Gulf Stream. The accumulation of the resulting debris of rocks forms the banks of Newfoundland.
These ice fields are of particular interest because of the fear they inspire, because of the shoals formed by their melting, and particularly because the chilling occasioned by their contact with an atmosphere warmer and more saturated with moisture, gives rise to heavy fogs. Hundreds of disasters would be avoided, enormous economy in the transportation of merchandise would be effected if we could succeed in understanding and foreseeing these phenomena. The admirable pilot charts published every month by the Hydrographic Bureau at Washington seek to solve the problem empirically, noting to what latitude the ice fields descend each year, observing their number, and establishing the probabilities concerning them according to the average of numerous observations. Fogs due to analogous causes—that is to say, to marine currents—are frequent in the northern or even the temperate region, on the North Sea, the English Channel, and on the Atlantic coasts of England and France. Everywhere they are the terror of sailors; ships move in them bewildered, advancing at the risk of running ashore or colliding with another vessel, while if they remain stationary they are in danger of being themselves struck, and in any case they lose time, that precious commodity whose price rises higher every day. The ability to foresee their presence, or if overtaken by them to find the course and follow it with certainty, would be the immediate consequence of the perfecting of oceanography.
Some attempts at this have been crowned with success. The position of a ship in the ocean is usually determined by the aid of astronomical coordinates. According to the observed position of a heavenly body, star or sun, the observer calculates his own position on the surface of the waves. Knowing where he is and where he is going, nothing is easier for him than to follow his course. But the indispensable condition is to see the star; this the fog renders impossible. This impossibility is the cause of most shipwrecks. However, the position can be otherwise determined. If we have a so-called bathymetric chart, plainly indicating by means of contour lines the depth of the water at each point, and another chart drawn up after a series of soundings and of preliminary analyses showing in the same part of the sea the changing nature of the bottom, here sand and there mud of one kind or another and there rocks, by a single cast of the lead a vessel lost in the midst of the ocean can determine her position. The depth of the sounding will confine the observation to the area for which the bathymetric chart gives this depth. If, moreover, care has been taken to fit the sounding lead with some means by which a sample of the bottom may be brought up, the area covered by this kind of bottom may be looked up on the lithologie chart, and, combining this information with the preceding, one will be able to ascertain his position almost exactly. Excellent applications of this method have been made in France by Commander de Roujoux and by Captain Trudelle for landfalls in different localities, along the Channel, at the entrance to New York, Havre, Brest, and the very dangerous approaches to Cape Guardafui. Two oceauographic coordinates have taken the place of the astronomical coordinates. The vessel, having lost her sight, makes use of feeling. To draw up bathymetrical and lithological charts is one of the principal objects of oceanography.
Oceanography has to maritime fisheries a relation still more important, if that is possible, than to geology, meteorology, and navigation, for this industry is related closely to the very life of nations. In France we have more than 86,000 marine fishermen, while more than 200,000 people derive, directly or indirectly, their means of existence from fishing; as, for instance, the men and women employed in the canning factories.
There are very many marine animals of which man makes use either as food, such as fishes, crustaceans, certain mollusks such as oysters and mussels, or to gratify his needs of all sorts, as sponges, pearls, coral, the great cetaceans, as whales or cachalots, and seals, from which he obtains oil and skin. No being escapes from the influence of the surroundings in the midst of which he lives and which govern his material existence as well as his manners, his morals, and his intellectual faculties. Nowhere are these restrictions more strikingly evident than in the water, probably because they are found there in a state of the greatest simplification or, to be more exact, the least complication. The laws of oceanography are, then, the rational basis for the conduct of fisheries, which have become methodical and consequently scientific, and pisciculture is a kind of agriculture of the sea.
In the harmony between a being and his environment, three cases present themselves: If the harmony is perfect, the being, finding the utmost satisfaction for his needs, develops and multiplies; if it is only partial, the being who suffers it becomes rare; if, finally, the harmony is absent, the being will disappear by flight if he possesses, like an animal, the power of motion, or by death if, like a plant, he is condemned to remain in one place. The living creature thus indicates in three ways the condition of his surroundings—by his presence, his rarity, or his absence. Dredgings made even in great depths show in a striking way the extreme specialization in the distribution of the animal species, among which some are evidently more sensitive to the environment, others less so. Each special group conforms to corresponding, special, exterior conditions, physical, chemical, or mechanical, and in this way the animal, vegetable, and, to a certain degree, even the mineral becomes an instrument of measurement, roughly graduated, it is true, because while abundance or absence are relatively easy to recognize, nothing is more vague and less determinable than degrees of rarity. A fish found in a certain locality indicates that the water there possesses a depth, a temperature, a certain limited range of salinity, a special kind of bottom and currents of calculable speed. All these details are implied in the presence or absence of this fish. Fishing is a problem which consists in knowing beforehand whether in such a place at such and such a time the fish will be abundant, rare, or absent. Other nations have fully recognized that the study of fisheries is, above everything, the study of the relations existing between the marine environment and the animal; that is to say, a question of zoology whose first basis is knowledge of the environment, which is a question of oceanography. They have put the principle in practice in their laboratories and in their official administrations, working out in detail the oceanography of a region before devoting themselves to zoological researches there. It is to be wished that this practice were more generally followed. It is a common sense law, but it is only too true that such are the slowest in making themselves known. Every improvement is simplification, and the men who cry unceasingly for simplicity are as if appalled when they come upon it unawares.
But if the presence or absence of a fish is so difficult to determine except by long and expensive trials, it is not so with the condition of the environment, which can be estimated and even recorded in figures, by means of instruments; temperature by the thermometer, density and salinity by the areometer, depth by the sounding line, the nature of the bottom by a lithological or chemical analysis. The instrument offers the advantage of having a perfect graduation, recording a sufficient number of degrees and consequently great delicacy of indication. On the other hand, it has the inconvenience of recording but one of the conditions of the surrounding of which the living creature records the whole. However, we must not forget that the purpose of science is, briefly, to discover what is above all others the most essential influence, and besides that if a single instrument is not sufficient, there is nothing to prevent our having recourse to many in succession. It would cost the fisher less time and trouble to measure the temperature and then, if it is necessary, the transparency and even the density in a certain region, then according to the results obtained set to work fishing with great probabilities of success, or to immediately leave the ground, than to cast his line and nets into the water, throwing his bait away hap- hazard, to learn finally only after a prolonged trial that the fish will or will not bite. Prof. H. Mohn, of Christiania, formerly head of the splendid Norwegian oceanographic expedition of the Vöringen, in 1876, found out[2] that at the Loffoten Islands the cod remained always in a bed of water between 1° and 5° in temperature (39° to 41° F.). According to his instructions a Government vessel, commanded by Lieut. G. Gade, went to ascertain the position in depth of this bed and to verify the scientific previsions. The success of this examination was perfect, and now Norwegian fishermen use the thermometer as a fishing apparatus. They seek a stratum having a temperature of 4° or 5°, the depth being variable not only in the same locality but also in the same region from time to time, and as soon as they find it they cast their lines and fish with certainty. The example is pertinent. It was furnished by an eminent scientist; it has received and still receives, every season, the sanction of practice and affords actual benefit to fishers. How eminently desirable it is that such a study should be made on the Newfoundland Banks or in Iceland, I mean in a serious way, by a competent person, and, as was done by the Norwegians, on board a vessel specially adapted for this research.
Other experiments no less interesting have been made in the laboratory of pisciculture in Flödevig. The Norwegians live by the sea; they are obliged to cultivate it, and, in fact, they declare that they have succeeded in restocking it with cod. Their processes are now being applied at Newfoundland by the English. It has been observed that the spawn of the cod must be raised in water of a certain temperature and density. If the water is too dense the young fish are not sufficiently strong to overcome its resistance and seek food on the bottom; if it is too light they easily reach the bottom, but have difficulty in holding themselves there, while if it is within the required limits of density, the animal, able to move at liberty, finds entire satisfaction of his needs and develops rapidly until, having reached his full strength, he ceases to be sensitive to the slight variations in his surroundings and can nourish himself in the sea where he is given his liberty. Breeding is carried on at Flödevig under perfectly systematic and scientific conditions, with the greatest benefit to the industry.
In the laboratory at Dildo, near St. John, Newfoundland, where similar restocking is carried on, the director, Mr. Nielsen,[3] discovered that the water in the breeding ponds for the male and female cod intended for reproduction must have a temperature from 4 to 7 degrees and that young cod, living well in water at zero, will die as soon as the temperature falls only half of a degree.
By reason of the development of science and general progress, war has become so difficult and frightful in its consequences for the two adversaries, neither of whom can ever be really victorious, that it is almost impossible between nations that are about equal in the scale of civilization. If nations wish to live and not be overwhelmed, peacefully but completely, by other peoples, their competitors in the terrible struggle for existence, they must use to their best advantage the riches of their territory, If agriculture, now scientific, obtains profit from the work of scientists who have transformed it from the collection of empirical recipes into a positive science; if we seek by knowledge of the soil, by suitable alternations of the crops, by appropriate fertilization to procure the best results from a piece of land, to make it produce a maximum of yield, we should do the same with the sea. We must admit that we are in this respect undeniably inferior to other nations. Still plunged in lamentable ignorance and regardless of the information obtained by careful scientific experiments, we ravage our coasts, and statistics show that the fishing industry is incapable of furnishing daily bread to those who practice it at the cost of so much trouble, fatigue, and danger. We profit by the sea as savages profit by the earth, when, according to the famous simile, finding a fruit tree in the forest they cut it down to gather its fruit. We have no complete and detailed map, not even a mediocre one, of the sea bottom, nor have we any exact ideas of the variations in temperature, in density, in salinity, along our coasts; we have not calculated the amount of sediment deposited by any of our great rivers; we are ignorant to what depth currents are felt and, except for a very small number of localities, as to their direction on the surface; we have no idea of their variations in intensity at different periods of the year. It is only too easy to add to this list of the data which we now lack. However full of good intention the measures of the administration may be, they are fruitless if they have not the intervention of authority to sanction the application of the measures approved by science. How can we be astonished by the poverty of our fishers and the fatal consequences which can not fail to affect the country? Fish are an important item in the economies of nations. According to statistics now somewhat old but rather increased than diminished by time, the world captures and consumes annually 2,000,000,000 francs worth of fish.
The industry of laying submarine telegraphs depends on oceanography to the same extent that the construction of railroads or canals depends on topography and continental geology. Perhaps the dependance of the telegraphs is even greater. The railroad and the cable follow the contour of the soil; both, for analogous reasons, must avoid too irregular ground, and the nature of the bottom is of the utmost importance. On certain bottoms swept by currents, as on the Wyville Thomson reef to the north of Scotland, the cable, subject to continual vibrations against the pebbles or frayed by their unceasing friction as they are washed about by the movement of the waves, wears out and breaks, however solid its envelope may be. At other times, on volcanic bottoms, as near Greece, for example, or in the Malay Archipelago, the cable may be stretched by displacement of the ground, causing changes in the level which break it.
The landing of the cables is no less important. Rocks are always very dangerous if they are situated in the zone of action of waves and tides. While in the open sea the land has every chance of being uniform, near the coast it often becomes irregular. It presents sudden declivities or deep hollows, reefs, straight crevasses bounded by almost perpendicular walls, such as M. Pruvot has recently discovered, not in some unknown corner of the Pacific or the South Sea, but in the Gulf of Lyon, some miles from the little port of Banyuls near Port-Vendres. A cable laid across such a valley is sure to break, and if the perfect knowledge of the topography of the region does not make the cause of the accident clear, we may be tempted to strengthen its envelope, that is to make it heavier and consequently more certainly provoke a subsequent rupture. It is not without reason that the English companies have in their service a fleet of telegraphic vessels intended for these studies alone, carrying a special technical staff, unceasingly employed in working on oceanography. They evidently guard against making known the obtained results, and are no more to be blamed for their secrecy than would be those contractors for building railroads who, provided with detailed maps of a region over which they have been ordered to lay a road, should conceal their documents, acquired laboriously and at great expense, from the engineers charged with overlooking their work and with paying them, and who on their side must, therefore, remain in ignorance of the topography and geology of the country. England holds the monopoly in the construction of submarine lines. France possesses only a small number, and, even of these, the larger part were built by the English. It is not enough to possess colonies beyond the ocean; it is necessary to be in direct communication with them. That we are at the mercy of foreigners for our telegraphic communications, the events of Siam and Madagascar furnish proofs painful to record.
II.
Oceanography is a science which applies to the natural phenomena of the sea, the precise methods of the exact sciences, mathematics, mechanics, physics, and chemistry.
It is a science of experimentation, of measurements, working by analysis and by synthesis toward the final end of learning the present history, and consequently the past and future history, of the earth, because all science which discovers and states laws is a prevision. Oceanography is thus a branch of geology, and since the soils stratified—that is to say, deposited—in the midst of the sea, formed by it, enter largely into that portion of the earth's crust which is directly accessible to our investigations, we would be authorized to claim oceanography as the most important branch of geology. It is ludicrous to hear arguments on the Silurian, the Devonian, or the Carboniferous oceans, now millions of years old, to hear discussions concerning their shores, their waters, or their currents, while we still know so little of our own ocean of to-day, on whose surface our vessels sail, into which we plunge our bodies, over whose immense circumference we are free to cast our gaze, with whose waters we moisten our lips if we wish, whose waves sing their monotonous and majestic harmony in our ears, of which we can take full possession by all our senses.
The foregoing considerations enable us to appreciate in its principal characteristics the method employed in oceanography. The application of experiment and of measurement seems at first particularly difficult, if not impossible. It is neither. As regards the ocean, it is certain that the phenomena apparent there are more than complicated—they are terrible; and their grandeur apparently puts them far beyond the power of man. It would be of no use to approach the study directly. However, even the forces of the sea are forced to yield to experimentation on condition that we proceed gradually, studying first lakes—oceans in miniature, governed by laws similar, although less complicated, and consequently more easy to discover and verify. In oceanography a phenomenon must pass through three phases of study: It is established on the ocean, found in lesser degree on lakes, and studied by synthesis in the laboratory. Thus its law is discovered. Then, taking the inverse order, it is ascertained whether the law is verified on lakes, and at last we come back to the ocean. We observe whether the law holds good there, and in case of modifications (which usually occur) we seek their causes and consider what new elements have become involved which were absent, or perchance ineffective, on lakes or in the laboratory. The study is now complete and definite, since, if necessary, we may return to the laboratory, where, rich in the suggestions which have arisen from our new survey, fortified by a first approximation, we can arrive at a greater precision, thanks to a new synthesis established by new experiments. We work from the known to the unknown and from the simple to the complex, retracing our steps if necessary.
The objection has been made to the experimental method that phenomena in miniature such as we can produce in the laboratory are not identical with natural phenomena, since they represent them on a reduced scale. This reasoning rests on a misunderstanding; everything goes to prove the contrary. Why should a heavy body left unsupported descend into the sea in any different manner than it descends in a tube some meters in height filled with salt water? If the changes are brought about by the duration of the fall, the depth, the pressure of the layers of water, and other circumstances, these changes can be studied and estimated by means of separate experiments. It is the usual method of resolving a natural phenomenon by means of curves of a single equation with multiple variables. Admitting that in certain cases a single experiment in the laboratory is insufficient to reproduce the phenomenon, yet a series of experiments, each of which would be performed to make clear the action of one of the components of the problem, would represent it in its entirety. When, for example, we have measured in a tube 3 or 4 meters long the duration of the fall of globigerina in sea water, we evidently do not learn all the laws of such a fall in the sea. It would be otherwise if, after having made the experiment with ordinary pressure, we repeat it with pressure more and more considerable, then with different temperatures, and each time note the variations resulting from the influence of each of these variables. Suppose that we have experimented carefully and tested separately everything that reason, ordinary common sense, points out as playing a part in the descent of dust particles through the ocean. If we then verify, first in a lake, then in the ocean, each of the laws discovered in the laboratory; if we determine that in the latter they are simply multiplied by a number, the constant coefficient of increase, we shall refute the critics. If there is a disagreement, we are apprised of the influence of some variable of which we have not taken account; and it will be necessary, after having discovered it, to experiment on it in turn. When all the work is finished we shall have the proof that, while with a single experiment taken separately we can not analyze nature, with the entire series we can do so.
It is thus that we should consider oceanography, which, proceeding upon the plan of not studying the past until the present is well understood, has introduced the experimental method into all that part of geology relative to sedimentary deposits. It is thus properly a branch of this science.
When a traveler, overcome by the long and painful ascent of a mountain, finally reaches the summit, he finds it pleasant to him to sit on a rock and, while recovering from his fatigue, contemplate the plain which he has crossed, the river whose windings he has followed and which at this moment spreads out below him, and also the difficult, even dangerous, ground, the sand, the marshes, over which he has come with great exertion. Certain stages of the journey had seemed to him short, others had appeared very long, and now he calculates what they are in reality. He distinguishes each error that he has committed. If, then, turning round, he looks down the other slope of the mountain, he sees what road he must follow to arrive surely and promptly at the end of his journey, visible afar in the mist of the horizon. What he has done gives him courage to complete his task; the victory he has won over fatigue and obstacles is the warrant of his victory over the fatigues and difficulties of the future. He gathers new ardor, strength, and hope. Is not this traveler like the man of science in his journey, laborious and painful as is all travail, toward the distant truth which, in his short life, he is certain never to reach? At least he will approach it at the cost of many mistakes. He has opened up the path, and those who follow behind him, profiting by his labor, will surpass him. They will go on farther and yet farther, obedient to that thirst for truth with which God has endowed every human soul as a mark of its divine origin and future immortality.
It is necessary to know the history of a science to understand those works with which it deals and to foresee those which remain for it to accomplish. Let us now show in the history of oceanography how its development has been influenced by different sciences and how it has influenced in its turn numerous others and their applications. It is the same in every stage of the intellectual improvement of humanity. We realize with difficulty the momentum (giving to this word the meaning usually assigned to it by physicists) of a new idea, which leads in its train a veritable world and pushes another on before it. This is, perhaps, the explanation of the difficulty with which a new idea overcomes the opposition it meets from a crowd of people and things that feel that after having lived they are about to disappear. Nothing consents to die, and routine is only an instinct of preservation.
Oceanography came in without noise. The human mind naturally seeks causes for that which is seen, or to better recollect them after they are discovered or even surmised, because of its very weakness it hastens to deduce laws for them. The first navigators were not impelled by curiosity which would have been incapable of fortifying their hearts with the triple armor necessary for facing the sea; they were moved by selfish interest and by want. The Phœnicians ventured upon the blue waves of the Mediterranean to provide themselves with slaves and metals to sell elsewhere and because it was impossible for them to live confined on the narrow strip of land bounded by the chain of mountains which separated them from hostile hordes. The Scandinavian pirates, on their light "drakkars" with curved prows crowned with the head of a dragon or bird of prey, fled through the rough waves and tempests of the North Sea from a vast but unfruitful fatherland where their time, which it was useless to spend in agriculture or in the tranquil arts of peace, was given up to social struggles, to perpetual combat, to victories and, consequently, to defeats, after which the vanquished was forced to submit to the vengeance or oppression of the vanquisher. Thus, not many years ago, the Polynesian, driven by famine from his island which had become too densely populated, flew in his pirogue with high sails of matting over the great swell of the Pacific. To all these voyagers the sea, despite its terrors, became a refuge. He who feels himself separated only by a few planks from moving abysses, where his gaze sees nothing when, profiting by the hollows in the waves, he tries to penetrate their depths, realizes that terrible forces too vast to be conquered by any human power surround and rule him, and that brute force avails nothing; it is necessary to call to his aid skill and science. All sailors are scientists, some more so, some less, according to their abilities, in order to elucidate the phenomena going on around them, of which they would be the plaything if they did not set to work in some measure to predict them in order to draw from them, first, security and then profit. How useful it would be to know the probable regions of calms and of storms, the strength and the direction of the currents, and the mutual connection of the phenomena of the earth, the heavens, and the waters, so that when one of them has been examined the other may be foreseen, and if it is to be feared, conquered. The more humanity advanced the more the sum of its known facts increased, the more indispensable it became to coordinate them, the more legend and empiricism became transformed into science.
Thus antiquity and the middle ages passed; thus these "sea rovers," as Michelet calls them, advanced—Icelanders, Arabs, Dieppois, and Basques. We can not admit that the sailors who then plowed the Atlantic, the Indian Ocean, and the seas of China could remain indifferent to the favorable or unfavorable circumstances whose advantages or dangers were the more worthy of attention since their ships were smaller and less capable of resistance than are the enormous vessels of the present day propelled by steam. It is only through skill that the weak are victorious. When the Norsemen about the year 1000 went from Norway to Iceland, from Iceland to Greenland, and from Greenland to that Vinland which five centuries later was to become America, they left in the places which they there discovered names which showed that natural phenomena had markedly attracted their attention; Straumsoe, the island of currents; Straumsfjorde, the bay of currents; Straumness, the cape of currents.
Suddenly, about the middle of the fifteenth century, the world experienced a great disturbance. The Renaissance began to make its influence felt throughout all Europe. There was a universal awakening of curiosity, of science, of ambition, of life; that is to say, of desire of enjoyment and of gold. There are such periods of fermentation in the lives of individuals as in those of nations. Their primary wants were satisfied, they desired more. The earth was divided among different races, each race divided into peoples, the peoples into provinces, the provinces into villages, hamlets, castles, all hostile to one another, warring, fighting, massacring, and being massacred. The least painful road for peaceful or for adventurous spirits, impatient with an ambition difficult to satisfy in the old countries, was now the sea. All nations launched out upon the waters. Some, Venetians, Genoese, sought riches and found them, others sought riches and rule over vast countries. The sea gave glory and fortune, asking in exchange only boldness, and valiant spirits of all nations, Portuguese, Spanish, Italians, French, English, and a little later Dutch, embarked on vessels. Columbus discovered America anew, a discovery that was not the result of chance. Admitting that he had not received formal assurance of its existence, he foresaw it, guided by his observations and oceanographic information, marred and distorted, but nevertheless collected and transmitted from mouth to mouth. At Porto Santo he had handled a piece of carved wood thrown upon the shore by the currents and during former voyages he had remarked that the western shores of Norway, Scotland, and Ireland were strewn with pieces of wood of unknown species brought by the waves from an unknown land. He, too, sought this land and found it.
When he reached it and, wishing to broaden the field of his discoveries, navigated that sea which was later to be called the Caribbean Sea and the Gulf of Mexico, he never relaxed his observation of the movement of the waters. At the "Serpent's Mouth," near the Gulf of Paria, he saw that the current turned to the west; he recognized this again on the coast of Honduras. Grouping the results of his experiments he formulated an hypothesis and declared that the sea in its advance followed the firmament from east to west. The true father of oceanography is the Gulf Stream. It seems as if men had invented the science solely to explain this current, which even to-day is the most studied and best known of the phenomena of the ocean. For many years all the sailing expeditions from Spain radiated around Hispaniola and Cuba. Ocampo sailed all around the latter island. In 1513 Ponce de Leon, having for pilot Anton de Alaminos (who had been pilot for Columbus in his last voyage), set out in search of the Fountain of Youth in Florida, and his vessel passed with difficulty through the waters whose current set with great force toward the north. A little later Diego Columbus, the son of the admiral, gathered together his data, combined them, and as Pierre Martyr d'Angleria recounts, asserted the continuity of this river of the ocean and that of the continent which checks it on the west and turns it back in a contrary direction. Scientific data appeared. Anton de Alaminos, after he had accompanied Cordova, then Grijalva, around Yucatan and the Gulf of Mexico, became chief pilot of Cortez when he went to seize the empire of Montezuma, and when the conqueror feared to be stopped by the jealousies and intrigues of his enemies in Cuba and Madrid, in order to baffle them, he charged his pilot to return in all haste to Spain and carry to the court dispatches, and particularly presents. Alaminos was the first to make use of his observations. To arrive more promptly he took the longer route, and leaving Vera Cruz turned his vessel toward the north of Cuba and the straits of Florida. We have here the three successive phases—the oceanographic discovery, its formulation and use for deductions, and lastly the putting it in practice.
All seas were traversed. Bartholomeu Dias discovered the Cape of Tempests; Vasco da Gama doubled it and entered the Indian Sea; Magellan and his Basque pilot, Sebastian del Cano, made the first voyage around the world; the Cabots, Jacques Cartier, Francis Drake, Hudson, Willoughby, and many others went from all coasts seeking empires or a more direct route by the north of America to India and China. Navigation and geography gave rise to the first observations relative to the sea. Each people, seeing, with reason, a competitor in every other people, took the greatest care to guard the secret of its discoveries. The Carthaginian boat, pursued by a more powerful Roman vessel, did not hesitate to cast itself on the coast and to break upon the rocks rather than indicate the way to the country of tin. Vasco da Gama in his war vessel massacred the crew and passengers of the poor Arabian boutre which he found laden with pilgrims in the Indian Sea. However, despite all efforts, the facts which could be made use of were slowly divulged, spread, and reached the ears of scientists, who arranged them and disseminated them with the power that had arisen with the recent invention of the art of printing.
Interest and curiosity awoke in proportion as knowledge developed. The era of geographic discoveries passed because there were no more empires to conquer. Competition died out and there began a period during which a passion for natural history seized the nations, while individuals bore proudly the title of naturalists. Travelers visited unknown islands and continents, gazed with wonder at the curiosities of these lands, and wished to describe them in detail. They did not at first consider whether or not this would be of any practical advantage, but confined themselves to the knowledge that these things existed, that the forms of plants and of animals were unusual, and this was sufficient to interest them. It was the epoch of enthusiasm. From the middle of the last century until about the middle of the present the world was enamored of social ideas, of political ideas, of art, literature, science, and even geography. They were taken by everything. Like children in infancy, they rejoiced almost without suspecting it in the supreme happiness of possessing a faith—often, indeed, two or three rather than one. Setting out boldly to discover the Utopia of their dreams, so long known and yet always so new and so full of charm, they traversed the oceans. Great voyages were made. In 1772 Cook went to Tahiti, accompanied by the naturalist Forster, to observe the transit of Venus. In 1815 the Russian Kotzebue went round the world on the Rurik, with the naturalist Chamisso; in 1820 the future Admiral Fitzroy took Darwin aboard his ship, the Beagle; Bougainville on the Boudeuse, De Freycinet on the Uranie in 1827, Vaillaut on the Bonite in 1836, and still others studied the natural history of all climates and brought back large collections. There was the same enterprise on land as on sea. Victor Jacquemont went to India overflowing with ardor, intoxicated with love of science at the aspect of the wonders and grandeur of nature. Those who were born half a century ago look back on a childhood and youth brightened by the last gleams of these emotions. We did not then have encyclopedias of scientific romances, the quintessence of human knowledge contained in 500 pages as the meat of an entire ox is concentrated into one small pot, and we were, for want of more or less substantial nourishment, forced to feed our minds with fancies. We began with the history of Sindbad the Sailor, the old man of the sea, the valley of emeralds and of rubies, over which the roc hovered, beating the air with great outspread wings. We went on with the library of voyages—Cook, Dampier, Carteret, Lapérouse, the reminiscenses of Jacques Arago, the blind man, and the adorable letters of Victor Jacquemont. With our books of pictures—and what pictures they were!—we could bask in the dazzling light of the equatorial sun; we breathed the odors of primeval forests, where the lofty cocoa palm waved its leafy top high over the thick undergrowth and the vast shades at whose feet the sleepy waves broke softly on the sandy beach of a desert isle; we looked out into the somber depths of starry nights. These were the feasts of thought. Over the open page of an atlas we dreamed, traversing the seas from the Tropics to the Poles, braving tempests and eternal ice, gathering incalculable treasures of poetic, thought, the consolation and often the strength of our mature age, which, after many years, dissipated, scattered in light smoke by the wind of the tempests of life, terrible and implacable as those of the ocean, reduced to no more than the humble denier, the widow's mite, remain still the joy and blessing of old age, which advances upon us with giant strides.
Just as the thirst for discoveries was assuaged because there was nothing more to discover, the thirst for natural curiosities diminished and in its turn disappeared. Many grew tired of being enthusiastic, of admiring, when they thought that they had seen everything; they grew more tired yet of cataloguing. Moreover, it was necessary to make other use of the riches acquired than giving a name to each object, placing samples of minerals in glass cases or cellars, samples of plants between sheets of paper in a herbarium, stuffing animals and setting them in line in a galley. Ideas became more serious; poetry and fancy gave way to science, which is in itself poetry and fancy. The intelligence of a man, following its natural bent, wished now to group the accumulation of facts in his possession under hypothetical laws, and he went to nature to verify the hypotheses suggested in his laboratory. Cook observed—that is to say, measured—the transit of Venus; Dumont d'Urville sought the southern magnetic pole; Sabine and Sir John Franklin went for the same purpose to the arctic regions. We gathered no more at random; we advanced toward a definite end.
Little by little, aided by the progress of chemistry and physics, the need of exactitude is making itself felt everywhere. We are applying it to oceanography. Realizing that it is indispensable to measure, we are no longer content to describe. We invent instruments, make chemical analyses, record figures, which are condensed facts, and true science, methodical and useful, is being evolved. At the head of each chapter on oceanography is found the name of a man of genius or of talent and an instrument. The currents of the sea have Franklin and the thermometer; the topography and lithology of submarine depths have Buache with his isobathic charts, Brooke and his detachable sounding lead, Delesse and his lithological charts; the chemistry of the sea has Forchhammer and his analyses; thermatics has Miller-Casella, then Negretti and Zambra with their differential thermometer; optics has Bérard with his porcelain plate, which shortly after becomes the disk of Secchi; physics, the mechanism of the waves, has Aimé with his mercury gage and the ball apparatus which he tested in the roadstead of Algiers, and the Weber brothers with their trough. All data are now reduced to graphical form constantly improved to approach nearer and nearer the truth, showing at a glance on each sheet of paper the picture of what is going on over the entire world in each order of phenomena, showing this even more clearly than it could be seen in nature, for on paper the phenomena are to some extent analyzed and dissected for easier comprehension of their components. We have leisure to examine separately and at the same time, by the superposition of charts having the same scale, the salinity, the temperature of the surface and of the depths, the meteorology, the contour of the bottom, its mineralogic constitution, the currents, waves, and all else. These charts permit us to combine, analyze, synthetize, experiment, sum up in every way, without fatigue or danger, without travel or loss of time. The scientist considers nature without leaving his laboratory, whither gathers the entire world to show itself in its slightest details and to unveil its mysteries.
I have not spoken of the author of theoretical and practical oceanography, founded on experimentation and measurement, as rigorous, considering the imperfections of the instruments employed, as in our own time. Marsigli founded it at one stroke. Born in Italy in 1658, successively engineer in the service of the Emperor Leopold I, slave in Turkey, member of the Academy of Sciences of Paris and of the Royal Society of Loudon, covered with glory, ignominiously degraded from all his titles and honors, a veritable Bohemian of science, who studied the sea in Provence and published the first didactic treatise on oceanography in Holland, and whose funeral eulogy was pronounced by Fontenelle. Marsigli rose suddenly, having had neither master nor precursor. Nothing was lacking to his work. It was complete—too complete, for though admired and appreciated by a few rare, eminent minds, among others the illustrious Boerhaave, he did not found a school. Oceanography, invented by Marsigli in the last years of the seventeenth century, fell into oblivion. One and a half centuries later, about 1842, his studies were taken up without much success by a Frenchman, Aimé. In spite of these two men of genius, who were merely isolated workers, the merit of important discoveries, and especially of methodical work continued uninterruptedly during a hundred years, gives to the United States the right to call themselves the founders of oceanography.
Applications of sciences result in new discoveries. The periods of ambition, of geographic discoveries, scientific discoveries, observations, generalizations, commercial or political interests, are evidently not clearly defined. They intermingle as they succeed one another. The mind goes back more than once over its steps, because attention is awakened by some point which has been passed over without attaching to it sufficient importance. Phenomena are connected with one another as are the studies to which they give rise. It is necessary for the success of the fishing industry that the formation and character of the sea bottom be noted and submarine lithology be observed, because the skate lives in mud, the sole in sand, and the gurnet among the rocks; zoology seeks to learn how temperature and salinity are distributed in the water; the telegraph industry needs very precise topo- graphic charts of the bottoms where it proposes to lay its cables. Discoveries multiply and every science develops with each generation of men.
As soon as a science is almost complete another replaces it, or perhaps two or three are founded together, for we see that natural manifestations, believed to be of a different order, are dependent in reality on the same law. Evolution is going on. Mineralogy is only a chapter of physics and chemistry; chemistry grew out of physics; physics grew out of mathematics; natural history is differentiating into groups and sciences; paleontology becomes paleozoology, a chapter of zoology, and paleobotany a section of botany; stratigraphic geology is paleoceanography and paleogeography; light is electricity; rhythmic vibration, measurable and measured, the wave—of sound, of light, of heat, of chemical action, of electricity—rules throughout the universe; barriers fall, matter follows the laws of the mind, everything advances toward scientific unity, as in the social domain everything moves toward unity of condition—that which assures to all, in the name of their common right to life, the maximum of happiness compatible with the human condition. There is slowly evolving a glorious moral and intellectual unity of truth, of science, of force, and of peace.
Though every nation aspires to this final end, each will reach it by different ways. While we hope for the day when all will possess the same intelligence because all will possess the same needs and the same ideal, this day has not yet, arrived. We see this in every event, no matter what it may be, literary, artistic, or scientific; we recognize it in the way in which oceanography has developed. The Englishman carries into his researches qualities of precision and boldness aroused by the thought of the practical utilization which he knows will result from his discoveries. The North German carries a temperament fond of work, but opinionated, slow, and diffuse; the Frenchman his ready-witted character, a discoverer, original but not persevering, submissive to routine, which he never ceases to execrate. The younger nations are profiting by the experience of their elders and inherit the improvements made in older times; they are endowed from birth with wealth of incalculable value inherited from former generations. They enter into action with the ardor, the boldness, and power of youth, and consequently with its success. They take the first rank, or will do so. They traverse in a few years all the phases which others took many centuries to pass through. In oceanography they undertake voyages of discovery, make geography, pure science, generalize, find practical applications. This is what is shown in the history of the development of the studies relating to the sea in the United States and Russia.