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circumstance of excessive heat in the weather, the gathering of the dark cloud, the deepening of the gloom, the lightning flash, or thunderbolt, often the destruction of buildings and animal life, the booming of the thunder, at a varying interval indicating distance, the deluge of rain-might all be described, partly recalling the experience of the pupils, partly awakening their minds to watch the next storm, partly extending their own observations by depicting the usual forms of the lightning, and stating instances of its effects, but not embarking upon the theory of atmospheric electricity, nor even naming it, further than to say that they will at some future time be made to understand a great deal more about the phenomena. Whether or not the teacher should use the opportunity of bringing forward the somewhat easy and yet interesting and intelligible fact that sound occupies time in reaching our ears, depends upon the course of the tuition. Such a fact might be previously brought forward in a lesson on Sound and Echoes; if this were so, it would receive a passing reference, and an impressive exemplification in connection with the lesson on Thunder. But as regards any lesson in Primary Science, the great caution is against overloading; the pupil must not be led to suppose that there is but one chance of explaining half a dozen natural laws stretching out into several sciences. Because all the sciences meet in Water, that is not a reason for embracing them all in a single lesson, nor indeed for attaching them to that one object. The laws applicable to water are applicable to a thousand other substances; many of these sufficiently familiar. The Tides might be given as a water lesson; but we may just as easily start it

under the name 'Tides,' as under the name Water. The most suitable designation would probably be The Tides of the Ocean.' Its regular place would be somewhere in Physical Geography; but it might be given at a still earlier point in the child's course.

When choosing an Object Lesson, we should think more of the principles to be taught than of the text; the selection of the text is only the second consideration. We must not be dominated by our text Object. We may make the Ocean the text for a lesson on the Tides, but we are not to be led off into facts regarding the ocean that are unconnected with the special phenomenon of tidal action. There is a unity in the subject of the Tides'; the unity belonging to an Object Lesson in the primary sciences-a phenomenal unity. There is no unity in the subject of the Ocean, until we have first determined what use we are to make of it.

The texts suitable for the present kind of lessons are given by a class of names different from the names of the two foregoing classes. There are names that point to natural objects-as water, iron, an oak, a horse, a star, a mountain; such are the starting points of the previous lessons-those in Natural History, Geography, and the like. There are other names that call to mind the processes, powers, and operations of the world-as weight, heat, dew, attraction, polarity, respiration; these are the names that give the most convenient start to the science lessons that we are now considering: although any one lesson might be associated with the more concrete names. A heat lesson might begin from water; an electricity lesson from iron: but this is not the course to be recommended; it has a false glare of simplicity. Each

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lesson should be taken for what it is, and connected with the name that best indicates and circumscribes it.

The Atmosphere' is a common example of the Object Lesson. It cannot be called a happy or a convenient starting point. Nothing could be a worse policy than to attempt to exhaust (if it were possible) the natural facts implied in it-its physical, chemical, and biological relations. We could merely nibble at them; we should teach nothing thoroughly; not to speak of the evil of perplexing the mind of the pupil. The proper use to make of the Atmosphere, as a text, would be the Natural History use; it would be an Individual or concrete lesson, whose properties or peculiarities should be simply enumerated as Natural History. Beginning with its position on the earth's surface, we might give its supposed height, its mass or weight, its gaseous character, its transparency. We then go on to its composition, which would require us to enumerate Nitrogen, Oxygen, Water, &c., with perhaps a word or two to render these as intelligible as the state of advancement of the pupils would allow. We should certainly reserve all questions connected with the origin of the water constituent or vapour, which would carry us out of the lesson into a totally different track; we could simply mention briefly that the water constituent was of variable amount, and, while in great part invisible like the others, had visible manifestations in clouds and mist, ending in rain. No more of that, if we mean to finish the lesson in its Natural History type. We then go on to a similarly guarded and severely curbed enunciation of the carbonic acid constituent-its amount, its character (as the gas

formed by the burning of charcoal, wood or coal), its function in supplying food to vegetation. There would still remain the smaller constituents, including the effluvia of the earth's surface, animal germs, &c., which could be simply mentioned, without being pursued.

To penetrate deeper into the mysteries of the atmosphere, to trace the numerous laws of causation involved in it, the lessons must follow other tracks, and be viewed in wider connections. An example or two will help to explain our meaning. The primary property of the atmosphere is the fact, not apparent at first glance, that the air is material and inert like the visible and tangible bodies around us. A very good object lesson might be contrived to exhibit this circumstance, which possesses the interest of agreeable surprise. The proofs and illustrations from resistance of the air, wind, and so on, are well known and highly impressive. But this lesson would really be a lesson on the inertness of matter; and would in fact have for its proper designation-Matter and Motion. As resistance to our energies, exhibited by solid and liquid masses, would be the first circumstance of the lesson, the illustration would be naturally carried out to air, thus establishing the material quality of the air. Then as to the weight and pressure of the atmosphere, there would be a natural alliance with a lesson on Gravity or Weight, which might be made intelligible at an early stage, although still in a considerable degree empirical. It would not be among the earliest lessons of a scientific tendency; for its adequate handling would presuppose the globular form of the earth, and some general conception of the solar system. Next to the weight of air, is its elasticity;

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this would come under a mechanical lesson on Elastic bodies or springs; from such a lesson we ought not to omit the spring of the air. Yet we could not properly follow out, in the same lesson, the interesting consequences of the spring or elasticity of air combined with gravity, as the rarefaction of the air in the upper regions; this would want a lesson to itself.

The constitution of the atmosphere as made up of Nitrogen and Oxygen appeals to Chemistry, and to Chemistry we must go, but on some other occasion. For the present lesson, Oxygen receives a few suggestive touches, yet only in empirical statements, shaped according to what is known of the pupil's previous course. best such statements are incomplete and unsatisfactory, if not even misleading; the only safeguard is, not to be carried away by an attempt to explain them.

At

The water constituent of the atmosphere, with its wonderful transformations and its perpetual cycle, is, if we may judge from the lesson books, a favourite topic of object teaching. The one fact of Dew is the more especial favourite; although in point of difficulty, it makes a very advanced lesson in Physics, as taught in a regular course. This is a good case for exemplifying what to do and what to avoid in the Object Lesson, and may help us to see the necessarily empiric character of the early scientific teaching.

Because the teacher is debarred by the capacity and knowledge of the pupils from a scientific lecture, it does not follow that he should be incapable of giving such a lecture, or be ignorant of the place that the subject would occupy in a connected syllabus of the Sciences. It is far better that he should know this, in order to