In the field of heat and molecular physics in general there is much better textbook material. Experiments here may legitimately be called precise, for the gas laws, temperature coefficients, and densities of gases and saturated vapor pressures will readily yield in comparatively inexperienced hands an accuracy of about one in a thousand. In the demonstrations emphasis should be given to the visualization of the kinetic theory points of view. Such models as the Northrup visible molecule apparatus are very helpful. However, in absence of funds for such elaboration, slides from imaginative drawings showing to scale conditions in solids, liquids, and vapors with average free paths indicated and the history of single molecules depicted will be found ideal in getting the visualization home to the student. Where we have a theory so completely established as the mechanical theory of heat it seems quite fair to have recourse to the eye of the senses to aid the eye of the mind. Brownian movements have already yielded up their dances to the motion picture camera. Need the "movies" be the only ones to profit by the animated cartoon?

Nor should the classical material be forgotten. Boys' experiments in soap bubbles have been the inspiration of generations of students of capillarity. And if the physicist will consult with the physiological chemist he will find a mass of material of which he never dreamed where these phenomena of surface tension enter in a most direct fashion to leading questions in the life sciences.

Enough has been said to indicate what we consider the methods of successful teaching of college physics. It is quite obvious, we think, that physics constitutes no exception to the rule that the teacher must first of all know and understand his subject. Right here lies probably nine tenths of the fault with our pedagogy. No amount of study of method will yield such returns as the study of the subject itself. The honest student, and every teacher should belong to this class or he has no claim to the name, is well aware that most of his deficiency in explaining a topic is in direct ratio to his own lack of comprehension of it. In physics, as in every other walk of life, we suffer from lack of thoroughness, from a kind of superficiality that is characteristically human but especially American. We have yet to know of any one who really ranks as a scholar in his subject from whom students do not derive inspiration and enthusiasm. Such a one usually pays little attention to the methods of others, for the divine fire of knowledge itself does not need much of tinder to kindle the torches of others. Our greatest plea is for our teachers to be men of understanding, for then they will be found to be men of method.

The sequence in which heat, electricity, sound, and light follow mechanics seems quite immaterial. Several equally logical plans may be organized. Preference is usually accorded one or the other on the basis of local conditions of equipment, and needs little reference to pedagogy. If one gives to mechanics its proper importance, the difficulty in giving instruction in the other topics seems very much less. The momentum acquired seems to serve for the balance of the year. Always must analysis be insisted upon, if our college course is going to differ from that of the high school. If we are to let students be content to read current from an ammeter with a calibrated scale and not have the interest to inquire and the ambition to insist upon the knowledge of how that calibration was originally made, we have no right to claim any collegiate rank for our courses. But if we define electrical current in terms of mechanical force which exhibits a balanced couple on a system in rotational equilibrium, there can be no dodging of the issue, for in no other way than by the study of the mechanics of the situation can the content and the limitations of our definition be understood. Any college work, so called, that does less than analyze thus is nothing more than a review and amplification of the material that should be within the range of the high school student and in that place presented to him. The first college course reveals a different method, the method of analysis. Science at the present time is so far developed that in no branch is progress made by mere description and classification. The method of analysis is dominant in the biological and the earth sciences as well as in the physics and chemistry of today.

On the more advanced college courses which follow the general physics course little comment is needed. Problems and questions here also exist, but they have a strongly local color and are out of place in a general discussion. The student body is no longer composed of the rank and file, half of whom are driven, by some requirement or other, into work in which they have but a passing interest at best. It is no longer a problem of seeing how much can be made to adhere in spite of indifference, of how firm a foundation can be prepared for needs as yet unrecognized in the subject of the effort. A very limited number, comparatively, enter further work of senior college courses, and these have either enthusiasm or ability and often both. Of course, a cold neglect or bored indifference in the attitude of the teacher will be resented. It will kill enthusiasm and send ability seeking inspiration elsewhere. But any one who is fond of his subject, and of moderate ability and industry, should have no difficulty in developing senior college work. If our instructor in the general course must be a scholar to be successful, the man in more advanced work must be one a fortiori. If he is not, few who come in contact with him have so little discernment as to fail to recognize the fact.

Organization of senior college work may be in many ways. One method where an institution follows the quarter system is the plan of having eight or ten different and rather unrelated twelve-week major courses which may be taken in almost any order. Half of these are lecture courses, the other half exclusively laboratory courses. There should be a correspondence of material to some extent between the two. Lectures on the kinetic theory of gases should have a parallel course in which the classical experiments of the senior heat laboratory are performed,—such experiments, for example, as vapor density, resistance and thermocouple pyrometry, bomb calorimetry viscosity, molecular conductivity, freezing and boiling points, recalescence, etc. A course of advanced electrical measurements should have a parallel lecture course in which the theoretical aspects of electromagnetism, the classical theories, and the equations that represent transitory and equilibrium conditions in complex circuits are discussed. In optics, likewise, there is ample material of great importance: physical, geometrical optics, spectroscopy, photography, X-ray crystallography, etc. The advanced student in these fields finds more elasticity and opportunity for cultivating a special interest in having a large number of limited interest courses from which to choose than in having such material presented in a completely organized course covering one or two years of complete work. Instructors who are specialists have opportunity of working up courses in their own fields which they do more efficiently under this plan. Research begins at innumerable places along the way, and the senior college courses so organized are the feeders of all graduate work.

In all of the above discussion it should be clearly remembered that no single plan or no one particular method has the final word or ever will have. As long as a science is growing and unfinished, points of view will continually be shifting. We are largely orthodox in our teaching. If brought up on the laboratory method of instruction it may seem the best one for us, but others may prefer another way which they have inherited. Let us appeal, then, for a constructive orthodoxy. Let us be as teachers of a subject to which we are devoted, truly and sincerely open-minded, quick to recognize and sincere in our efforts to adopt what is better wherever we meet it: waiting not to meet it, either, but going out to seek it. From the humblest college to the greatest university we shall find it here and there. Not alone in schools but in the legion of human activities about us on every hand are people who are doing things more efficiently, more thoroughly, and more skillfully than we do things. If we would be of the number that lead, we must be among the first to recognize these facts and profit by them.

First, let our work be organized with respect to that of others—the high schools; not discounting their labor but having them truly build for us.

Second, let us be open-minded enough to see that all methods of instruction have their advantages and make such combinations of the best elements in each as best suit our purpose.

Above all things, let us know our subject. Here is a task before which we quail in this generation of vast vistas. But there is no alternative for us. No amount of method will remove the curse of the superficially informed. Let us devote ourselves to smaller fields if we must, but let us not tolerate ignorance among those who bear the burden of passing on, with its flame ever more consuming, the torch of knowledge.

Harvey B. Lemon
University of Chicago

VII

Though basally historical, a large part of the literature of geology is concerned with the description of rocks, structural features, geologic terrains, surface configurations and their modes of formation and means of identification. A notable part of the text prepared for college students relates primarily to phenomena and processes, leaving the history of the earth to follow later in a seemingly secondary way. This has its defense in a desire first to make clear the modes of the geologic processes, to the end that the parts played by these processes in the complexities of actions that make up the historical stages may be better realized. This has the effect, however, of giving the impression that geology is primarily a study of rocks and rock-forming processes, and this impression is confirmed by the great mass of descriptive literature that has sprung almost necessarily from the task of delineating such a multitude of formations before trying to interpret their modes of origin or to assign them their places in the history of the earth. The descriptive details are the indispensable data of a sound history, and they have in addition specific values independent of their service as historical data. But into the multiplicity and complexity of the details of structure and of process, the average college student can wisely enter to a limited extent only, except as they form types, or appear in the local fields which he studies, where they serve as concrete examples of world-forming processes.

The study of these structures, formations, configurations, and processes yields each its own special phase of discipline and its own measure of information. The work takes on various chemical, mechanical, and biological aspects. As a means of discipline it calls for keenness and diligence in observation, circumspection in inference, a judicial balancing of factors in interpretation. An active use of the scientific imagination is called forth in following formations to inaccessible depths or beneath areas where they are concealed from view.

While thus the study of structures, formations and configurations constitutes the most obtrusive phase of geologic study and has given trend to pedagogical opinion respecting its place in a college course, such study is not, in the opinion of the writer, the foremost function of the subject in a college curriculum that is designed to be really broad, basal, and free, in contradistinction to one that is tied to a specific vocational purpose.

While we recognize, with full sympathy, that the subject matter of geology enters vitally into certain vocational and prevocational courses, and, in such relations, calls for special selections of material and an appropriate handling, if it is to fulfill these purposes effectively, this seems to us aside from the purpose of this discussion, which centers on typical college training—training which is liberal in the cosmic sense, not merely from the homocentric point of view.

To subserve these broader purposes, geology is to be studied comprehensively as the evolution of the earth and its inhabitants. The earth in itself is to be regarded as an organism and as the foster-parent of a great series of organisms that sprang into being and pursued their careers in the contact zones between its rigid body and its fluidal envelopes. These contact zones are, in a special sense, the province of geography in both its physical and its biotic aspects. The evolution of the biotic and the psychic worlds in these horizons is an essential part of the history of the whole, for each factor has reacted powerfully on the others. An appreciative grasp of these great evolutions, and of their relations to one another, is essential to a really broad view of the world of which we are a part; it is scarcely less than an essential factor in a modern liberal education.

Let us agree, then, at the outset, that a true study of the career of the earth is not adequately compassed by a mere tracing of its inorganic history or an elucidation of its physical structure and mineral content, but that it embraces as well all the great evolutions fostered within the earth's mantles in the course of its career.

Greatest among these fostered evolutions, from the homocentric point of view, are the living, the sentient, and the thinking kingdoms that have grown up with the later phases of the physical evolution. It does not militate against this view that each of these kingdoms is, in itself, the subject of special sciences, and that these, in turn, envelop a multitude of sub-sciences, for that is true of every comprehensive unit. Nor is it inconsistent with this larger view of the scope of geology that it is, itself, often given a much narrower definition, as already implied. In its broader sense, geology is an enveloping science, surveying, in a broad historical way, many subjects that call for intensive study under more special sciences, just as human history sweeps comprehensively over a broad field cultivated more intensively by special humanistic sciences. In a comprehensive study of the earth as an organism, it is essential that there be embraced a sufficient consideration of all the vital factors that entered into its history to give these their due place and their true value among the agencies that contributed to its evolution. A true biography of the earth can no more be regarded as complete without the biotic and psychic elements that sprang forth from it, or were fostered within its mantles, than can the biography of a human being be complete with a mere sketch of his physical frame and bodily growth. The physical and biological evolutions are well recognized as essential parts of earth history. Although the mental evolutions have emerged gradually with the biological evolutions, and have run more or less nearly parallel with them—have, indeed, been a working part of them—they have been less fully and frankly recognized as elements of geological history. They have been rather scantily treated in the literature of the subject; but they are, none the less, a vital part of the great history. They have found some recognition, though much too meager, in the more comprehensive and philosophical treatises on earth-science. It may be safely prophesied that the later and higher evolutions that grace our planet will be more adequately emphasized as the science grows into its full maturity and comes into its true place among the sciences. It is important to emphasize this here, since it is preëminently the function of a liberal college course to give precedence to the comprehensive and the essential, both in its selection of its subject matter and in its treatment of what it selects. It is the function of a liberal course of study to bring that which is broad and basal and vital into relief, and to set it over against that which is limited, special, and technical, however valuable the latter may be in vocational training and in economic application.

In view of these considerations—and frankly recognizing the inadequacies of current treatment—let us note, before we go further, what are the physical and dynamic boundaries of the geologic field, that we may the better see how that field merges into the domains of other sciences. This will the better prepare us to realize the nature of the disciplines for which earth-science forms a suitable basis, as well as the types of intellectual furniture it yields to the mind. Obviously these disciplines and this substance of thought should determine the place of the science in the curriculum of any course that assumes the task of giving a broad and liberal education.

Earth-science is the domestic chapter of celestial science. Our planet is but a modest unit among the great celestial assemblage of worlds; but, modest as it is, it is that unit about which we have by far the fullest and most reliable knowledge. The earth not only furnishes the physical baseline of celestial observation, but supplies all the appliances by which inquiry penetrates the depths of the heavens. Not alone earth-science, as such, but several of the intensive sciences brought into being through the intellectual evolutions that have attended the later history of the earth, have been prerequisites to the development of the broad science of the outer heavens. The science of the lower heavens is a factor of earth-science in the definition we are just about to give. At the same time, the whole earth, including the lower heavens, is enveloped by the more comprehensive domain of celestial science.

If we seek the most logical limit that may be assigned the realm of earth-science, as distinguished from that of celestial science, of which it is the home unit, it may be found at that borderline within which any passive body obeys the call of the earth, as against the call of the outer worlds, and without which such a passive body obeys the call of the outer worlds, the call of the sun in particular. This limit is the dynamic dividing line between the kingdom of the earth and the kingdom of the outer heavens. This boundary, according to Moulton, incloses a spheroid whose minimum radius is about 620,000 miles, and whose maximum radius is about 930,000 miles. We may, then, conveniently say that the earth's sphere of control stretches out a million kilometers from its center and that this defines its true realm. At the same time, this defines the logical limit of the earth's ultra-atmosphere and appears to mark a zone of exchange between the ultra-atmosphere of the earth and the ultra-atmosphere of the sun. It thus appears to imply the place and the mode of an exchange of vital elements upon which probably hangs the wonderful maintenance of the earth's atmosphere for many millions of years and the equally wonderful regulation of the essential qualities of the atmosphere so that these have always remained within the narrow range subservient to terrestrial life. It is needless to add that this regulation also conditions the present intellectual status of the thinking factor among the inhabitants of the earth out of which—may I be pardoned for saying?—has grown the present educational discussion.

If this last shall seem to squint toward special pleading, let it be considered that, as we see things, it is precisely those views that take hold of the issues upon which our very being and all its activities depend, that serve best to train youth to broad views and penetrating thought. Such thinking seems to me to form the very essence of a really liberal education.

Not only is this definition of the sphere of geology comprehensive, but it has the special merit of being dynamic, rather than material. Such a dynamic definition comports with the view that earth-study should center on the forces and energies that actuated its evolution, since these are the most vital feature of the evolution itself. It is important to form adequate concepts of the energies that have maintained the past ongoings of the earth not only, but that still maintain its present activities and predetermine its future. It is the study of the forces and the processes of past and of present evolutions that constitute the soul of the science, rather than the apparently fixed and passive aspects of the earth's formations and configurations which are but the products of the processes that have gone before. Even the apparent passiveness of the geologic products is illusive, for they are in reality expressions of continued internal activities of an intense, though occult, order. These escape notice largely because they are balanced against one another in a system of equilibrium which pervades them and gives them the appearance of fixity. To serve their proper functions as sources of higher education, the concepts of the constitution of the earth should penetrate even to these refined aspects of physical organization and should bring the whole into harmony with the most advanced views of the real nature of physical organisms. This removes from the whole terrestrial organism every similitude of inertness and gives it a fundamental refinement, activity, and potency of the highest order. To form a true and consistent concept, the enveloping earth-science must be assumed to embrace, potentially at least, the essentials of all that was evolved within it and from it, with, of course, due recognition of what was added from without.

The history of the earth should therefore be taught in college courses as a succession of complex dynamic events, great in the past and great in future potentialities.

The formations and configurations left by the successive phases of action are to be studied primarily as the vestiges of the processes that gave them birth, and hence as their historic credentials. They are to be looked upon less as the vital things in themselves, than as the record of the events of the time and as the forerunners of the subsequent events that may be potential in them. And so, primarily, the geologic records are to be scrutinized to find the deeper meanings which they embody, whether such meanings lie in the physical, the biological, or the psychological world.

Turning to specific phases of the subject, it may first be noted that geology is singularly suited to develop clear visions of vast stretches of time; it opens broad visions of the panorama of world events, a panorama still passing before us. While the celestial order of things no doubt involves greater lapses of time, these are not so easily realized, for they are not so well filled in with a succession of records of the passing stages that make up the whole. But even the lapses of geologic time are greater than immature minds can readily grasp; however, their powers of realization are greatly strengthened by studying so protracted a record, built up stage upon stage. The very slowness with which the geologic record was made, as well as the evidences of slowness in each part of the record, help to draw out an appreciation of the immensity of the whole. The round period covered by the more legible range of the geologic record rises to the order of a hundred million years, perhaps to several hundred million years. The large view of history which this implies has already come to form the ample background on which are projected the concepts of the broader class of thinkers; such largeness of view will quite surely be held to be an indispensable prerequisite to the still broader thinking of the future for which the better order of students are now preparing.

While this is preëminently true of the concept of time, the concept of space is fairly well cultivated by geologic study, though far less effectively than is done by astronomical study. Astronomy and geology work happily together in contributing to largeness of thought.

The study of the origin and early history of the earth brings the student into touch with the most far-reaching problems that have thus far called forth the intellectual efforts of man. If rightly handled, these great themes may be made to teach the true method of inquiry into past natural events whose vastness puts them quite beyond the resources of the laboratory. This method finds its key in a search for the history of such vast and remote events by a scrutiny of the vestiges these events have left as their own automatic record. This method stands in sharp contradistinction to simple speculation without such search for talismanic vestiges, a discredited method which is too often supposed to be the only way of dealing with such themes. To be really competent in the field of larger and deeper thinking, every courageous mind should be able to cross the threshold of any of the profound problems of the universe with safe and circumspect steps, however certain it may be that only a slight measure of penetration of the problem may be attainable. A well-ordered mind will remain at once complacent and wholesome when brought to the limit of its effort by the limit of evidence. The problem of the origin of celestial worlds, of which the genesis of the earth is the theme of largest human interest, is admirably suited to give college students at once a modest sense of their limitations and a wholesome attitude toward problems of the vaster type. Without having acquired the power to make prudent and duly controlled excursions into the vaster fields of thought, the mind can scarcely be said to have been liberalized.

From the very outset, the tracing of the earth history forces a comprehensive study of the co-workings of the three dominant states of matter massively embodied in the atmosphere, the hydrosphere, and the lithosphere, the great terrestrial triumvirate. The strata of the earth are the joint products of these three elements and constitute their lithographic record. These three coöperating and contending elements not only bring into view the three typical phases of physical action, but they present this action in such titanic aspects as to force the young mind to think along large lines, with the great advantage that these actions are controlled by determinate laws, while the causes and the results are both tangible and impressive.

While there is a large class of tangible and determinate problems of this kind, embracing shiftings of matter on the earth's surface, distortions of strata, and changes of bodily form, there are also problems of a more hidden nature such as internal mutations. These give rise to mathematical, physical, and chemical inquiries while at the same time they call into play the use of the scientific imagination and are thus rich in the possibilities of training. Thus in varied ways geological work joins hands with chemical, physical, mechanical, and mathematical work.

When life first appears in the record, there is occasion to raise the profound question of its origin, and with this arises a closely related question as to the nature of the conditions that invited life, which leads on to the further question, what fostered the development of life throughout its long history? While the obscurity of the earliest record leaves the question of origin indeterminate for the present, duly guarded thought upon the subject should foster a wholesome spirit toward inquiry in this vital line as well as a hospitable attitude toward whatever solution may finally await us. In all such studies the student should be invited to look to the vestiges left automatically by the process itself for the answer, and he should learn to accept the teachings of evidence precisely as it presents itself. So also when a problem is, for the present, indeterminate, it is peculiarly wholesome for the inquirer to learn to rest the case where the light of evidence fails, and to be complacent in such suspension of judgment and to wait further light patiently in serene confidence that the vestiges left by the actuating agencies in their constructive processes are the surest index of the ultimate truth and are likely to be sooner or later detected and read truly.

In the successive records of past life impressed on strata piled one upon another until they form the great paleontologic register, there is an ample and a solid basis for the study of the historic evolution of life. With this also go evidences of the conditions that attended this life progress and that gave trend to it. This record of the relations of life to the environing physical conditions forms one of the most stimulating fields of study that can engage the student who seeks light on the great problems of biological progress. Here geology joins hands with botany and zoölogy in a mutual helpfulness that is scarcely less than indispensable to each.

Following, or perhaps immediately attending, the introduction of physiological life, there appeared signs of sentient life. The preservation of certain of the sense organs, taken together with the collateral evidences of sense action, as early as Cambrian times, furnish the groundwork for a historical study of the progress of sentient life, eventuating in the higher forms of mental life. Here the problems of geology run hand in hand with the problems of psychology. The limitations of the evidence bearing on psychological phenomena, while regrettable, are not without some compensation in that they center the attention on the simpler aspects of the protracted deployment of the psychological functions.

In addition to the clear evidences of psychic action, in at least its elementary forms, there appeared early in the stratigraphic records intimations of some of the relationships that sentient beings then bore to one another; and this relationship gives occasion to study the primitive aspects of sociological phenomena. If nothing more is learned than the important lesson that sociology is not a thing of today, not an untried realm inviting all kinds of ill-digested projects, but on the contrary is a field of vast and instructive history, the gain will not be inconsiderable. There are intimations of the early existence and effective activity of those affections that precede and that cluster about the parental relationship, the nucleus of the most vital of all the sociological relationships. In contrast to the affections, there are distinct evidences of antagonistic relations, of pursuit and capture, of attack and defense; there were tools of warfare and devices for protection. In time, a wide-ranging series of experiments, so to speak, were tried to secure advantage, to avoid suffering, to escape death, and to preserve the species. There were even suggestions of the cruder forms of government. The many stages in the evolution of the various devices, as well as the stages of their abandonment, that followed one another in the course of the ages recorded the results of a multitude of efforts at sociological adjustment. They raise the question whether a common set of guiding principles does not underlie all such relationships, earlier and later, whatever their rank in our scale of valuation. And so this great field of inquiry—too narrowly regarded as merely humanistic—comes into view early in the history of the earth. The geological and the sociological sciences find in it common working ground. If the geologic and the humanistic sciences are given each their widest interpretation and their freest application, the advantage cannot be other than mutual.

It is perhaps not too much to say that studies in the physiological, the psychological, the sociological, and the allied fields necessarily lack completeness if they do not bring into their purview the data of their common historical record traced as far back as it is found to contain intimations of their actual extension.

It is customary to speak of the geologic ages as though they were wholly past; they are, indeed, chiefly past as the record now stands, but time runs on and earth history continues; the processes of the past are still active, and they are likely to work on far into the future. And so geologic study links itself fundamentally into all such present terrestrial interests as take hold of the distant future. The forecast of the earth's endurance, attended by conditions congenial to life and to the mental and moral activities, hinges on a sound insight into the great actuating forces inherent in the earth, together with those likely to come into play from the celestial environment. All human interests, in so far as they are dependent on a protracted future, center in the prognosis of the earth based on its present and its past. The latest phases of geologic doctrine prophesy a long future habitability of the earth. They thus give meaning and emphasis to the deeper purposes sought in all the higher endeavors, not the least of which is education, particularly those phases of education that lead to effects which may be handed down from age to age.

Out of all this vast physical, biological, and psychological history, the things to be selected for substance of thought and for service in mental training in a college course are, first of all, those that are either fundamental in themselves, or that have vital bearings on what is fundamental. These are chiefly the great dynamic factors, the agencies that gave trend to the master events, the forces that actuated the basal processes by which the vast results were attained. The material formations and the surficial configurations that resulted are to be duly considered, to be sure, for they form the basis of interpretation and they are, besides, the repositories of economic values of indispensable worth; but, as already urged, in a course of intellectual training, these are to be regarded rather as the relics of the great agencies and the proofs of their actions, than as the most vital subjects of study, which are the agencies themselves. As already remarked, the geologic formations are to be treated rather as the credentials of the potencies that reside in the earth organism, than as the vital things themselves. The vestiges of creation and the footprints of historical progress embody the soul of the subject; they constitute the chief source of inspiration to those who aspire to think in large, deep ways of really great things. It is of little value, from the viewpoint of liberal culture, to know that there is a certain succession of sandstones, shales, and limestones; that professional convention has given them certain names, more or less infelicitous in derivation and in phonic quality; but it is of vital consequence to learn how and why these relics of former processes came to be left as they were left, and thus came to be witnesses to the history of the far past. It was a wise thing, no doubt, that the fathers of geology strongly insisted that there should be a rigorous and rather literal adhesion to the terrestrial record in all earth studies, because in those times of transition from the loose, more or less fantastic thought that marked the adolescent stage of the human race, it was imperative that students should stick close to the immediate evidence of what had transpired, and should withhold themselves from much enlargement of view based on the less tangible evidences; but at the present stage, when the general nature of the earth's history has been firmly established, it would be an error on the part of those who seek for the most liberalizing and broadening values of the science, to treat the record merely as a material register of immediate import only, to the neglect of the less tangible but more vital teachings immanent in its great forces and processes. The seeker of liberal culture should direct his attention to the great events, and, above all, to the larger and deeper meanings implied by these events.

And so—may I be pardoned for reëmphasizing?—the teacher of geology whose essential purpose is liberal training, leading to broad and firm knowledge and to sound processes of thought, will critically observe the distinction between geology taught appropriately from the collegiate point of view, and geology taught specifically from the professional and technical points of view. In these latter, specific details in specific lines are important, and may even be essential, but it is the function of the college teacher of geology to select from the great mass of material of the science such factors as are basal, vital, and talismanic. He will give these emphasis, while he neglects the multitude of details that lack significance as working elements or as landmarks of progress, whatever their value in other relations. This selection is equally important, whether applied to the great physical processes that have shaped the earth into its present configuration, or to the great chemical and mineralogical processes that have determined its texture and its structure, or to the great biological and psychological processes that have given trend to the development of its inhabitants.

Even if the undergraduate course in geology is pursued less for the purpose of liberal culture than as a means of preparing for a professional career as an economic geologist, no essential departure from an effort to master first the basal features and the broader aspects of the science, especially the dynamic aspects, is to be advised. The shortest road to declared success in professional and economic geology lies through the early mastery of its fundamentals. No doubt immediate and apparent success may often be sooner reached by a narrower and shallower study of such special phases of the subject as happen just now to be most obviously related to the existing state of the industries; but industrial demands are constantly changing—indeed, at present, rather rapidly—and new aspects follow one another in close succession. These new aspects almost inevitably spring from the more basal factors as these rise into function with the progress of experience or the stress of new demands. Those who have sought only the immediate and the superficial, at the expense of the basal, and especially those who have neglected to acquire the power and the disposition to search out the fundamentals, are quite sure to be left among the unfortunates who trail behind; they are little likely to be found among those who lead at the times when leadership counts. In the judgment of those master minds that lead in affairs and that take large and penetrating views, the lines along which the most vital contributions to economic interests are being made connect closely with basal studies of the actuating agencies that condition great enterprises. In the judgment of the writer, it is a false view to suppose that any short, superficial study of so vast a subject as the constitution and history of the earth can result in economic competency. In so far as time for study is limited, it should be concentrated on the great underlying factors that constitute the essentials of the science. It is here assumed that men who care to take a college course at all are seeking for a large success and are ambitious for a high personal career. If they look ultimately to professional work in economic lines, they may safely be advised that the straight road to declared success lies in a search for the vital forces, the critical agencies, and the profound principles that make for great results, not along the by-paths whose winding, superficial courses are turned hither and thither by adventitious conditions whose very nature invites distrust rather than confidence.

Turning to some of the more formal phases of treatment, three types of work are presented: (1) the use of nature's laboratory, the world itself, (2) the use of the college collections and laboratories, and (3) the use of the literature of the subject.

(1) Fortunately, there is no place on the face of the earth where there is not some natural material for geologic study, for even in the most artificialized locations geological processes are active. In crowded cities these processes may be easily overlooked, but yet they are susceptible of effective use. Within easy access from almost every college site there are serviceable fields of study, and these, in any live course, will be assiduously cultivated. They may be relatively modest in their phenomena; they may seem to lack that impressiveness which has played so large a part in the popular notion of the content of geology, but they may nevertheless serve as most excellent training grounds for young geologists. If students are so situated as to be brought at the beginning of study under the influence of very impressive displays of geologic phenomena—precipitous mountains, rugged cliffs, deep cañons, and the like—there is danger that their mental habits may become diffusive rather than close and keen; the emotions may be called forth in wonder rather than turned into zest in the search for evidence. If students are to be trained to diligence in inquiry and to the highest virility in inference and interpretation, it is perhaps fortunate for them if they are located where only modest records of geological processes are presented for study. In such regions they are more likely to be led to scrutinize the field keenly, sharply, and diligently for data on which to build their interpretations. The scientific use of their imaginations is all the better trained if, in their endeavor to build up a consistent concept of the whole structure that underlies their field, they are forced to project their inferences from a few out-crops far beneath the cover of the adjacent mantle that shuts off direct vision. Few teachers have, therefore, any real occasion to long for richer fields than those accessible to them, if they have the tact to render these fertile in stimulus and suggestion.

(2) Laboratory work upon the material collected in the field work, as well as laboratory work upon the college collections, are essential adjuncts. Ample provisions for this supplementary work, however modest the appointments, are important and can usually be secured by ingenuity and diligence in spite of financial limitations.

Both field and laboratory work should be well correlated with one another and with the systematic work on the text that guides the study, so that each shall whet the edge of the other and all together accomplish what neither could alone.

(3) The text selected should be such as lends itself, in some notable degree at least, to the general purposes set forth above. It should be supplemented, so far as may be, by judicious assignments for reading and for special study. Lectures may be made a valuable aid to the discussions of the classroom, but with college classes they can rarely be made an advantageous substitute for the discussions. Lecturing, so far as used, is best woven informally into the classroom discussions. Supplementary lecturettes may be advised if they are of such an informal sort that they may almost unconsciously take their start from any vital point encountered in the course of discussion, may run on as far as the occasion invites, and may then give way again to the discussion with the utmost informality. Such little participations in the work of the classroom, on the part of the teacher, are likely to be cordially welcomed. At the same time, if well done, they will set an excellent example in the presentative art as also in an apt organization of thought.