There are many things in Mr. Mendenhall's article, in the December number of the Monthly, to which I fully agree, and for which I heartily thank him. With his permission, I should like to add a supplement.

Much of the difficulty encountered in teaching Natural Philosophy is of the same nature as that presented in other sciences requiring the use of the syllogism; but it is often increased by the suppression of one of the premises which the tyro will not or can not supply. Many of the demonstrations, doubtless, seem to the beginner to be based on the lucus a non lucendo principle, and many of the principles on which the science is founded, are rather accepted than comprehended even by the most mature intellects. At the same time, Natural Philosophy presents a great variety of facts and principles which a mere child can readily explain without assistance from any one, or which he may easily master when the conditions are fairly stated. The main difficulty then lies in selecting such portions of the science as are adapted to the age, ability, and previous training of the pupil. Authors

generally compile text-books with reference to an ideal class, having ideal capabilities and ideal attainments: the teacher is fortunate when his class corresponds in all respects with the one supposed by the author, for then his work goes on with little frietion by virtue of its own momentum. We thus have text-books on Physics for colleges, for academies, for grammar schools, and for home instruction. These books are graded with reference to the use required of them, and, to say the least, the teacher has a large list to select from, and is bound to choose the one best adapted to his wants, which is in all cases one a little above the average comprehension of his pupils. It is also required of the teacher to be above his text-book so far as to warrant him in assuming to be the authority in mooted questions, and to enable him to supply the incidental defects of want of accuracy, completeness, and clearness. These defects should be pointed out to the class before the sections containing them are studied, that there may be no work done which must be undone; lest, as Mr. Mendenhall suggests, there remain in the mind of the pupil the taint of old error.

There is another consideration respecting text-books which should not be overlooked, and which I hope, at some time, to present at length. The Natural Sciences are generally regarded as having their main value in the educational curriculum through the mass of useful facts presented; but as a means of mental discipline, they are all invaluable when rightly used. This is especially true of Natural Philosophy, from its close connection with applied Mathematics. From this point of view, that text-book on Physics is the best, that mode of teaching is the most desirable, which so presents the theme as to show the logical connection of the parts, the dependence of facts, apparently remote, upon the same common principle, the generalization of many principles into universal laws. The good judgment of the teacher will determine how much of logical method is available in the given circumstances of his pupils. Little children may learn many desirable facts, but children of larger growth should go farther and fare better.

As regards the mode of presenting the subject, I think that teachers often err in doing too much themselves, leaving too little to be done by their pupils. There is no one, even the laziest, who

does not experience great satisfaction in the mental elasticity which succeeds the strain required for the mastery of great truths. Of course there is a limit to mental as well as physical elasticity, but no elasticity whatever is manifest except under the previous application of some external force. Suppose an experiment has been performed not explicitly stated in the text book, but comprehended in the general principles adduced, if the majority of the class do not at once "see through it," let its explanation pass for a day or for many days, stirring up their minds occasionally by way of remembrance. Give them at times full permission to talk the matter over among themselves, and at other times withhold the privilege.

The experiments, as a rule, should be exhibited before the explanation of the principles involved is attempted; but not before they have read over the matter in their text-books. Where, as in connection with the air-pump, there are many experiments illustrating different properties, the experiments should be classified in accordance with the specific property illustrated, and the class should be required to prove the existence of the property by the experiments. When it is possible, the experiments should be performed with apparatus that the class may make at home. The importance of experiments in fixing facts and principles in the minds of the pupils, is not generally recognized. Too often they are regarded merely as affording the class a sort of relaxation from the monotony of recitation. They are proofs of facts, and should always be required in the statements of facts.

In my own experience, I have found it profitable to develop some one theme with each class beyond the limits of an ordinary text-book, merely to impress the pupils with the extent and capabilities of the subject, but deriving thereby much other good both to myself and them. In this way I have worked out thoroughly at different times, but not all with the same class, for want of time, specific gravity, the pendulum, mirrors, the steam engine, polarized light, etc., etc. In each case, it cost me much thought and labor to bring the various ramifications of the several themes to the average comprehension. Sometimes I found it necessary to devote the study of a week to contrive the apparatus and develop the method for the simple elucidation of the principles involved. I have pursued this plan for several years, and intend

to persevere in it for the sake of keeping out of the old ruts of thought and labor. Let no one say that the themes mentioned are easy until he has written out exactly what he wishes to give his class in place of the matter in the text-book. Let any one make one trial of this, and he will make many.

Another thing has often troubled me, which is the amount that ought to be learned by each pupil. Many topics in any text-book are of so inconsiderable importance that it seems a waste of time and strength to burden the mind of the student with them, especially if it involves the exclusion in part of weightier themes. The themes that I consider unimportant may not seem so to others, but all will agree that some are merely burdensome. What shall be done with such? My plan has been to require these as a sort of reading lesson, and to give in a short lecture the facts that are most worthy of remembrance, and require nothing in recitation beyond a quiz on the lecture. Without some such precaution, I find my pupils are prone to study over the invention of some useless trinket, or through a wordy explanation of a self-evident proposition, with as much painstaking care as upon the steam-engine, or the law of gravitation.

The mathematical bugbear is the lion in the way of younger pupils, and oftentimes bars further advance. Yet mathematical formulæ are so valuable that their application at least should be mastered if possible. I think a little pains on the part of the teacher will give even very young pupils enough of algebra to comprehend the properties of a simple equation. My own pupils study Natural Philosophy before making much progress in mathematics, so that I sometimes find it necessary to give a lesson or two in the latter science.

Teachers, however, must not expect to find many philosophers among their pupils even after the most intelligent training. Mr. Mendenhall's class contains as large a proportion as any that I ever saw; viz., one in eight. I do not think that this small proportion is due to any inherent mental deficiency; but that it is almost entirely caused by poor training in the lower grades of schools. Young children are not taught to think for themselves as they should, and this reacts upon them throughout their educational course.

OBJECT TEACHING IN THE OSWEGO SCHOOLS.

[The following is the concluding portion of a "Report on Object Teaching" read at the late meeting of the National Teachers' Association by Prof. S. S. Greene, of Rhode Island, in behalf of a committee consisting of seven of the most eminent educators of the country:]

We come now to the final question: Does the plan pursued at Oswego conform to these general principles?

We answer unhesitatingly—in the main it does. It may not be right in all its philosophy, or in all its practice. Whether the practice is better than the philosophy, or the philosophy than the practice, we will not pretend to say. Neither is it our object or purpose to appear as champions of the system, to defend it against attacks, or cover up what is faulty. We simply appear to report it, and our opinions upon it, so far as the examinations of one week will enable us to do.

But what is the Oswego system? The schools of the city-a city of some twenty-three thousand inhabitants-are divided into four grades: Primary, Junior, Senior and High,-corresponding to the Primary, Secondary or Intermediate, Grammar and High schools of other cities. Besides these grades, there is an unclassified school continued through the year, to meet the wants of pupils who are not well adapted to the graded schools; and yet another kept in winter, to accommodate those who can attend only during that season. Each grade is subdivided into classes named in the order of rank from the lowest, C, B, A. Something like the object system was introduced in 1859. But in 1861, these peculiar features were more fully developed. Previous to the last date, the schools were in session six hours per day. Since that time the daily sessions have been shortened one hour in all the schools.

The peculiar system called the "object system " was introduced at first into only the Primary grade. In 1861, it had gained so much favor with the School Board, that a Training School was established under the direction of Miss Jones, from the Home and Colonial Institution, London. At present the system has reached the Junior schools, and now prevails throughout the two lower grades.

The Training School, which forms a prominent feature of the