CONTENTS.

OLD SERIES, Vol. XV.........NEW SERIES, Vol. VII.

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 friction 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