living infusoria, daphnia, and gammarus; histology, in a stained hydra, and the nuclei of the red corpucles of frog's blood; vital phenomena, in the pulsation of the "hearts" and dorsal vessel of a live anesthetized earthworm and in the beating heart of daphnia; and chemical and physical phenomena, shown by testing starch with iodine and then boiling the starch to exhibit the swelling of the grains and their change to a translucent condition.]

HIGH-SCHOOL INSTRUCTION IN PHYSICS

F. M. GILLEY, INSTRUCTOR IN SCIENCE, HIGH SCHOOL, CHELSEA, MASS.

ment.

Of the three ways of presenting the subject of physics, by the recitation or text-book, the laboratory, and lecture methods, the latter, tho perhaps the oldest, is not now utilized to its full extent. It has been more or less modeled on the practice of the colleges and technical schools. By lectures suitable for high-school classes should not be understood a formal discourse, but rather an informal talk, interrupted from time to time by questions and suggestions by the class. The teacher should assure himself, by questioning, that the descriptions and experiments have been understood. It may be well to repeat, of course rapidly, some important and fundamental experiments four or five times, the purpose being to fix a scientific fact by seeing the experiment repeated, instead of seeing the experiment once, and afterwards studying and committing to memory the record and description of that experiAt intervals, the reading of notes just taken by the pupil should be called for and the more common errors in note taking corrected without the laborious use of the blue pencil. Coaching in athletics and teaching in manual training are done on the spot, as it were, and are more effective than written or verbal criticisms that come to the pupils hours too late. It is not to be expected that young children will know how to take notes at the beginning of the study of science. In fact, one of the peculiar advantages of science study (and this is especially the case in physics), is the invaluable training in note taking. The pupil soon learns to take notes at any time, to condense and edit, as it were, the lessons developed by the teacher and the class. There is training in writing in simple language on topics where a lack of clearness is only too self-evident. The pupil finds the data he has recorded the basis of computations that give him further and more definite knowledge. Carelessness in experimenting, observing, or recording, or in following instructions, any inaccuracies or omissions, bring their own punishments. Note taking should be practiced during the lecture, laboratory, and recitation periods.

The set division, however, of school periods into lecture, laboratory, and recitation is hardly desirable in high-school work. The ideal way is to combine a little of the three in each lesson. The exercise may open

with a few minutes' talk, an experiment may be shown and the class questioned, perhaps on some essential point that needs to be emphasized. Then let the laboratory work follow. The uncertainty of just what is to be the form of instruction excites the curiosity and holds the interest of the class.

Physics as taught by the lecture method alone is usually non-mathematical, and is superficial and easily forgotten. Its impress on the future thinking of the pupil is soon lost if it is the only method of presenting the subject. Whenever possible, laboratory exercises should be the foundation for lecture and recitation work. There is at present a demand, largely from those who have not delved into the real science of physics, for a broad but brief course, especially as preliminary to a laboratory course. This general course, sometimes given for a whole year, is much like the tour of a conducted party, perhaps good for the health, and interesting like a view of the earth from a flying machine. General information, the humanizing portions of the subject, engines, meters, pumps, motors, telescopes, X-rays, wireless telegraphy, etc., the things that go, practical applications, must, from lack of duplicate pieces of apparatus, be taught from the lecture table. The past fifteen years has seen a great development of laboratory courses and apparatus. There is just as much or more room for advance in apparatus for lecture-table work. It may be said that the physics that is now taught, or should be taught, is the creation of the last twenty-five years, during which time. few additions have been made to the old and obsolete apparatus so long in use.

Of the questions asked from motives of curiosity of an educated or a supposedly educated man, how many, either directly or indirectly, refer to some department of physics? The history of modern civilization, one might almost say, dates from the introduction of the steam engine. Comfort and luxury have been brought within the reach of everyone by the application of the steam engine and by the electrical discoveries and inventions of the last half century. Physics, being fundamental to chemistry, meteorology, astronomy, at least should be begun early in the high-school course. The first and second years are not crowded, and the mind has not come completely under the influence of the prevailing method of studying exact mathematics and ancient languages. Young pupils learn physics because they like to; the upper classes, always burdened by a variety and amount of work, study physics often because they are driven to it. Partly because of college entrance requirements, physics for the college section at least has been removed from the second year to the third and fourth years of the course. Since a large proportion of the college classes prefer to continue other subjects instead of beginning a new one, the percentage of pupils studying physics has somewhat decreased in the last ten years. If the full benefit

of physics is to be obtained, it should be studied in the first two years of the course, before habits of study have been formed by other subjects. It is the only science subject in which definite lessons for home work can be assigned for every lesson. It is somewhat immaterial in what order the several grand divisions are studied, and selections suitable for firstyear pupils are easily made.

Teach from your own convictions, and do not lean on the authority of others. Familiarize yourself with some of the mechanic arts. In these days when fortunes and positions in the business world come to those of practical rather than theoretical or academic training, it would perhaps seem superfluous to urge upon science teachers the necessity of acquiring a varied range of mechanical skill. A man in the world at large was once rated according to what he knew, but now according to what he can do. The science teacher, especially the teacher of physics, is no exception. A more or less handy knowledge and skill in the simpler portion of glass grinding, glass blowing, wood and metal working, are of the highest importance. While teachers would seldom think of grinding lenses for pupil's use, still some skill in this line of work clears up many difficulties for the teacher and awakens an interest in the subject of light. Skill in the use of tools is valuable, not so much for any apparent saving in the cost of apparatus made by the teacher, but because that skill is put to use in constructing pieces of apparatus that are a pride to the teacher and the class. The interest evolved in this way turns work into play. The art of presenting physics by lectures, the use of the lantern, the making of photographs and lantern slides should be acquired by every teacher of physics. In the training of a teacher, instruction in a good high school counts for more than that received in college; for teachers are wont to teach as they have been taught, and the methods and general style of presentation and drill of the high-school course are better models for them to follow.

The college course can be improved, for those at least who are to teach, by introducing a broader general course in physics. Why cannot there be a body of lecturers who in turn might spend a week each year in residence, much after the plan of the boards of preachers in our universities? In the way suggested the best talent could be obtained, men famous for their attainments in the arts and sciences. The biographies of great scientists, their stilted portraits, exert a less potent influence than personal contact with men who have done and are doing the work of the world's progress. Many men who have not the time, strength, or general diffuseness of scientific knowledge to make them. ready to fill the chair of physics in some university are well fitted by lecturing on their specialities to arouse a lasting enthusiasm in college students. Modern language departments bring across the seas men who have written things of note to give courses of lectures. Why should not

the science departments bring men who have done things in the world? The advancement of science and its applications becomes doubly interesting when explained by the very scientists and inventors themselves.

Ask any of your pupils in physics, and in the most advanced classes, too, "how much of your algebra do you find useful?" "Only a little of all we learned," will be the answer. The complicated expressions so common in algebraic problems seldom occur in actual practice in applied mathematics, at least in work likely to fall to the lot of a mechanical or electrical engineer. The dozen or more cases of factoring, the intricate problems in two or more unknown quantities, are not made much of outside the algebra class. Just examine the algebraic statements of a number of even difficult problems. Once stated the solution of the algebraic equation is usually very easy. It is, in fact, impossible to invent prob. lems that when stated in equations are nearly as difficult as the majority of the equations given in the text-books for solution.

In plotting algebraic equations, much practice is obtained in substitution, most useful in physics and all applied mathematics. Formulas can be used as tools by one who is skillful in substitution. Much less algebra of a simpler and more practical nature in the high school would help the physics teacher and save time in the mathematic course for other work usually neglected; for instance, trigonometry. In arithmetic some attention could be paid to shortened methods of multiplication and division, to the number of places of significant figures, and to rough checks in computation. It takes some time in the physics course to overcome the idea that in estimating the capacity of a tank the carrying out of the product to several places does not make up for careless measurement of the dimensions. Plane geometry has been burdened by additional theorems first set on college examination papers and afterwards incorporated into the course. And just as a mechanical tool catalog is enlarged by new inventions (does the mechanic use them all?) so the amount of geometry the ambitious teacher tries to teach grows by the addition of the new originals invented each year by the college examiners.

At the British Association in 1901, almost without exception the leading mathematicians and scientists approved a syllabus of a course in mathematics presented by John Perry. He advocates the illustration of important propositions in geometry by drawings, the use of the sine, cosine, and tangent functions and abandonment of almost all demonstrative geometry. He argues that we should reason about things rather than ideas; that we think too much of logic and too little of the matter to which that logic is applied.

A little mathematics of this practical type makes physics a more serious and scientific study. As in the case of the new pronunciation of Latin first advocated in England twenty-five years ago, and today almost universally used in this country and not at all in England, so the more attractive

and less artificial course in mathematics outlined by Professor Perry will, I think, be introduced in this country long before it makes great progress in England. Why is it that the whole elementary algebra is studied before geometry and trigonometry are taken up? Cannot the interesting yet simple portions of trigonometry, geometry, and analytics, at least the use of squared paper, be taught along with algebra? The time when a Latin grammar was learned by heart before beginning simple translation is long gone by. Physics offers a use for the practical field of mathematics, and on much the same basis as in actual life. The computations of the data of an experiment have a reality not possessed by examples in algebra or arithmetic.

Practice in laboratory work should in general precede and be made the basis of class-room and text-book instruction. The actual contact with and use of apparatus gives the pupil a set of standards by which he can interpret intelligently scientific writings and follow with profit experiments performed on the lecture table. If this order of instruction is followed, the "wire edge" will not be taken off the pupil's appetite. The laboratory work being taken up first is new and fresh, and the supplementary lecture work will contain as much new matter as the pupil can receive without confusion. Why is it that the individual method of laboratory instruction is general? No one now thinks of such a method in Latin or mathematics; for in those subjects all are at one time giving attention to the same thing, and the answer of one pupil assists the others. The class is taught as a whole, and one pupil at any time is as far advanced as the others, and no farther. In the individual or go-asyou-please method commonly in use today in the teaching of physics the pupils follow printed or copied directions. As each difficulty arises, and much the same difficulties are met some time or other by every student, the teacher is called upon to settle that difficulty for each individual pupil, and the teacher moves around the class answering questions. here and there, adjusting apparatus and distributing supplies as if he were the servant, instead of the teacher, and as if he were directed by, instead of directing, the class, while all the time he bemoans the large number in the class and the little time he has for each one. The end of the lesson finds the pupils at different stages of advancement and the teacher exhausted by the almost impossible task of directing at one time as many classes as there are pupils in the class. Dr. Sargent, of the Hemenway Gymnasium, was once asked if he could develop a man without the class work of the gymnasium. "Yes," he replied, "but I should become a wreck myself."

in which the class is After giving instrucbefore giving further

Let us consider a totally different method, one taught as a whole and the teacher directs the class. tions for the first step, wait until all have finished instructions. If any question is asked, consider whether that question is