mental principles, because, altho the element of drill is present, the element of intelligibility is wanting. The subject is not brought down to the level of the understanding of the pupil. He is made to learn a lot of meaningless formulae, and to apply these formulae in stock problems, the method of solving which he learns by rote. The course becomes to him useless drudgery, because he does not know what it is all about. In my judgment, the poor grasp of principles, of which our college examiners complain, is more often due to this type of course than to the former type. Into such a course I would not infuse the element of amusement, but rather the element of intelligibility, the element of interest, which invariably follows as soon as the course becomes intelligible; and it is to make the course intelligible that I say that the first duty of every teacher, both in order of time and of importance, is to place the phenomena of physics, about which all physical reasoning is grouped, before the pupil, both by laboratory exercises, and by classroom demonstrations.

I am confident that I shall arouse no opposition when I say that every elementary course in physics which is worthy of the name must be built up about some sort of an experimental outline. It is therefore self-evider.t that the performance of the experiment, or experiments, upon which a given part of the course is based should precede all textbock study of these experiments, or of the conclusions deduced from them. The chief, almost the sole, aim of a text is to assist the teacher in the discussion and interpretation of experiments. It is in no case to relieve him of the necessity of doing experiments. It enables him to cover very much more ground than could otherwise be covered, since it makes it possible to abridge description, discussion, and illustration, wherever these are of such a nature that they can be just as well obtained from the text. It furthermore enables the pupil to study at his leisure, and critically, experiments and conclusions which have been rapidly. presented in class.

In my judgment, the demonstration work of a class should not, in general, be given in the form of set lectures. The experiments should be performed and informally discussed by the class and teacher, and this discussion should be followed, first by the textbook's explanation and discussion of these, or of similar, experiments, and later by problems or questions involving applications of the principles learned. It need scarcely be said that every good teacher will of course make the most intimate and vital connection possible between the experiments of the classroom and the phenomena of daily observation.

But, someone asks, why have lecture demonstrations at all? Why not build up the course entirely about a laboratory outline, and let the student perform all of his own experiments? This plan has often been tried, and it has some advantages; and yet it too unquestionably represents a method of instruction of very low efficiency, for there are many experiments which can be performed with great saving of time, and with great saving of expense in the way of apparatus, and at the same time without any loss in the pedagogical results obtained, if they are performed by the teacher before the class, instead

of being performed by each individual. For example: if expansion by heat is to be illustrated by the old ring and ball experiment, it is just as convincing to the student to see someone else try to push the ball thru the ring and fail, as to try to do it himself. Furthermore, there are many experiments which the student can easily understand when he sees them, but which require, for their proper performance, a manipulative experience and skill which he does not possess. Many of the projection experiments in optics fall under this

head.

Just how the experimental outline of the course is to be divided between the laboratory and the classroom, and just what type of experiment shall go to the laboratory and what to the classroom, are matters of great importance which are often given very insufficient consideration. Perhaps the blunder of placing essentially laboratory experiments in the class work is more frequent than the reverse. The assigning of all qualitative work to the classroom and all quantitative work to the laboratory is an artificial and illogical division. There are many qualitative experiments, like those which have to do with the reading of thermometers, or other instruments which but one or two observers can see at once, which go much better in the laboratory than they do in the classroom. Again, there are other qualitative experiments, like those met with in the study of static electricity, which the student must do himself, and which he must perhaps repeat a number of times, if he is to grasp their meaning thoroly. These, of course, should be assigned to the laboratory. And incidentally what a refreshing thing an occasional qualitative experiment in a laboratory manual is to the pupil!

On the other hand, there are some quantitative experiments, like the experimental verification of the laws of falling bodies by means of the inclined plane, which can be done as classroom demonstrations to very much better advantage than as laboratory exercises, for the reason that they can be seen by a large class and that the accuracy of the results depends upon a manipulative skill which a student will not in general have. There are other experiments, like that of the verification of the parallelogram of force, which the teacher will want to do roughly in class and afterward have the students repeat more carefully in the laboratory. As a general rule it is of course true that the quantitative experiments will go to the laboratory and the qualitative ones to the classroom. But the point which needs to be emphasized most strongly is that the students must not under any circumstances be left to get their knowledge of the experiments which constitute the backbone of the course from reading about them in the textbook. They must see them at first hand.

A word as to the characteristics of a good lecture demonstration. They are: first, that it be observable to the whole class, and not merely to one or two; and second, that the principle to be illustrated be not confused by unnecessary complexity in the apparatus employed. In other words, the demonstration ought to be, as far as possible, an illustration of one principle, not an illustration of many. For example, experiments in induced electricity

may be performed with a mirror galvanometer which throws a spot of light upon a screen. This satisfies the condition of being visible to the whole class, but it violates the condition of not being as simply and readily intelligible as possible. It is better, if possible, to perform these experiments with a pointer galvanometer, which doesn't involve an optical principle which the students may or may not be familiar with in addition to the electrical principle which it is desired to make clear. There is, however, no way of showing exactly what lecture demonstrations seem to me to be desirable and what undesirable except by going thru the whole range of physics and indicating a complete list of demonstration experiments. Since this is obviously impossible in the short time at our disposal I have selected a few experiments which seem to me to be representative of good classroom exercises. They are of course not new and could scarcely be new, else they would have no place in elementary physics. The first has to do with the illustration of the principle of electro-magnetic induction; the second with the classroom illustration of the difference in wave-length of red and green light; the third with the darkening of the D Fraunhofer line when the beam of sunlight is passed thru incandescent sodium vapor, and the last with the classroom demonstration of the properties of electrons.

DISCUSSION

FRANKLIN T. JONES, registrar and science teacher, University School, Cleveland, Ohio. The main point which I wish to emphasize in my discussion of this paper is-that the demonstration lecture should be a time-saver. Before taking up that phase of the subject I wish in a few words to champion the habit of memorizing certain things in all branches of science. We have come to look down on the teacher who drills on definitions. In history and literature in many schools it is true that the pupil is compelled to reproduce by topic the substance of a certain paragraph. It is likewise true that some science teachers compel the same type of recitation. No defense can be offered for such a practice, but when we turn to the other extreme and say "No memorizing," our position is equally indefensible. Frequently verbatim servile memorizing is the only way to assure the acquisition of a clearcut description which in the pupil's own words would be vague, inaccurate, and unscientific. Repetition of this statement with its added meaning as the idea becomes familiar

means growth.

The only criterion I wish to propose for the selection of a lecture demonstration is that it be a time-saver. By that I mean (1) it must make possible the explanation of a fundamental principle in less time; (2) it must hasten the assimilation of the principle by the pupil; (3) it must be something worth illustrating. A great deal of time is frittered away even by the best and most careful teachers in illustrating by experiment things that do not need illustration. Adaption of experiment to the class to which it is to be presented is a problem for the teacher to solve. Let him always ask when he performs an experiment-Is it saving time?

One great source of time dissipation is the laboratory. Very frequently experiments there given are more suitable for the lecture table and the pupil would learn just as much by seeing and calculating as by doing the whole experiment himself. Still further time may be saved by eliminating long and tedious experiments whose results are more easily obtained either by description or even on authority.

How much time may be thus saved and what is to be done with it? Time-saving as a motto will carry a teacher over the proper subject-matter of elementary physics in six

months, twenty-four weeks, one-hundred and twenty exercises-a saving of one-third. Should the extra time be devoted to the explanation of the new theories, to pretty demonstrations, to doing advanced work? Only in part. The major portion should be devoted to review, to the turning over of old facts from new points of view, answering suggestive questions, working problems, thinking. As teachers we have much to learn from the methods of the correspondence schools who emphasize fundamentals, stimulate thought, and inspire hard work by pointed questions.

N. HENRY BLACK, science master, Roxbury Latin School, Roxbury, Mass.-Since in the main I agree with the two gentlemen who have just preceded me, I will not take your time to point out the little things wherein we disagree, but will call your attention to the great value of the lecture-table experiment as a means of arousing genuine interest. The student's interest is bound to be kindled when he can quickly grasp the physical principle involved in an experiment. The subject becomes more real, concrete, and vital. In the lecture the teacher can throw in many side lights in the way of historical references, personal experiences, and practical applications.

In order that the lecture-demonstration may do its work effectively, it is very essential that it go. This means good apparatus, and considerable skill and practice in manipulation. Then, too, the demonstration must have a point which the student easily sees. This means simple and large apparatus. But it is also essential that the demonstration be not merely a clever show which impresses the student much as a slight-of-hand performance. It should rather be a co-operative effort on the part of the teacher and the student. Often an experiment which apparently fails at first, may be made very instructive by finding out the cause of the failure. Sometimes the students themselves can really help in the preparation and performance of lecture experiments. This is especially true of lantern-slide talks. But the fact is that in our efforts to develop the laboratory and inductive side of physics in our secondary schools, we have neglected the lecture demonstration. Why is it? The teachers have had no special preparation for this work. In the colleges and normal schools, the professors, often too busy in the management of the laboratory work and their own research, do not take the time to prepare first-class lecture demonstrations. Much of the apparatus in our schools for the lecture-table experiments (even what little there is) is flimsy and toylike. American apparatus dealers have done much to develop good school laboratory apparatus. Now we want them to turn their attention to simple, large, strong lecture-table apparatus. Finally the greatest drawback in the way of good work in this direction is the fact that not enough time is given the teacher properly to prepare himself and the apparatus.

PRESERVATION OF THE NATURAL RESOURCES OF
THE UNITED STATES

DR. HERBERT A. SMITH, EDITOR "FOREST SERVICE," UNITED STATES

DEPARTMENT OF AGRICULTURE

I am not here in order to talk on this subject simply as a matter of general interest. I am here because I want to present it particularly to teachers. I believe that it has an important relation with the specific work and the problems of the teacher; and before I get thru I hope I shall persuade you that it is so. Otherwise I shall be sorry that I came.

Professor Baily and I are here to present to you what are really two different parts of one great subject. It is a subject which in sober words-and I do not believe in sweeping statements-seems to me to be beyond all others the most important which can now be brought before the American people. It

is the problem of how, by the application of deliberate forethought and trained intelligence, to make the most of ourselves as a nation.

We have, as we now see, suffered tremendously from waste-waste of natural resources and waste of human life. This is only one side, the minor side, of the matter. Under all there is a much bigger thing than merely to cut off the waste. When we total the amount we pour into the sea, let go up in smoke, and blot off the face of the map by the destruction of the productive power of the land, the aggregate loss is a staggering one. When we think of the waste of human life thrown upon the junk heap and into the garbage pit of society, the wreckage that fills our poorhouses, jails, and slums, besides our vast sacrifice to preventable accident and disease, when we appreciate what it would be to society if all these men and women were efficient members of the industrial body, we see that here also is enormous loss.

But that is the minor part of the thing. A possibility is before us so big that it is hard for even the imagination to take in at once. Yet it is not the imagination of a visionary. Suppose we bring to bear this principle of the application of trained intelligence to making the most of the land, the water, the forests, and the mines, and making the most of the men and women whose labor is the only thing that gives value to these resources; looking at it from the narrowest and lowest, the purely economic standpoint, what a country this would be to live in!

But there is something much greater involved than mere material progress. There is a new conception of citizenship and service. To my mind President Roosevelt never spoke a more admirable word than the concluding passage in his address before the White House Conference in Washington last May.

Finally [said the President] let us remember that the conservation of our natural resources, though the gravest problem of today, is yet but part of another and greater problem to which this nation is not yet awake, but to which it will awake in time, and with which it must hereafter grapple if it is to live-the problem of national efficiency, the patriotic duty of insuring the safety and continuance of the nation. When the people of the United States consciously undertake to raise themselves as citizens, and the nation and the states in their several spheres, to the highest pitch of excellence in private, state, and national life, and to do this because it is the first of all the duties of true patriotism, then and not till then the future of this nation, in quality and in time, will be assured.

Now this is where the affair touches the teacher. There is here, if I see it aright, not merely an economic problem; there is a tremendous moral problem. Will you permit me to say a few words as one of you, one who was for a number of years himself a teacher, and has always had a keen interest in the problems of the teaching world?

A few years

ago we were in the midst of the fight between the cultural studies and the scientific studies; then between the studies that were disciplinary on the one hand and the studies that were either cultural or practical on the other. Now we have the question in the new form of vocational studies as against the training for citizenship. I believe that the great coming need in all education is going to be vocational education. The same thing is true whether you look