moon, besides doing the like, first increases slowly night after night, and then wanes, by-and-by reappearing as a thin bright streak, with the rest of her disk so faintly perceptible as to seem only half existing.
Added to these commonest and most regular occupations and manifestations, are various others, even more striking—comets, meteors, and the aurora with its arch and pulsating streams; flashes of lightning, rainbows, halos. Differing from the rest and from one another as these do, they similarly appear and disappear. So that by a being absolutely ignorant, but able to remember, and to group the things he remembers, the heavens must be regarded as a scene of arrivals and departures of many kinds of existences; some gradual, some sudden, but alike in this, that it is impossible to say whence the existences come or whither they go.
Not the sky only, but also the earth's surface, supplies various instances of these disappearances of things which have unaccountably appeared. Now the savage sees little pools of water formed by the rain-drops coming from a source he cannot reach; and now, in a few hours, the gathered liquid has made itself invisible. Here, again, is a fog; perhaps lying isolated in the hollows, perhaps enwrapping every thing, which came a while since and presently goes without leaving a trace of its whereabouts. Afar off is perceived water—obviously a great lake; but on approaching it the seeming lake recedes, and cannot be found. In the desert, what we know as sand-whirlwinds, and on the sea what we know as water-spouts, are to the primitive man moving things which appear and then vanish. Looking out over the ocean, he recognizes an island known to be a long way off, and commonly invisible, but which has now risen out of the water; and to-morrow, just above the horizon, he observes an inverted figure of a boat, perhaps by itself, or perhaps joined to an erect figure above. In one place he sometimes perceives land-objects on the surface of the sea, or in the air over it—a fata morgana; and in another, over against him on the mist, there occasionally comes into view a gigantic duplicate of himself—"a Brocken spectre." These occurrences, some familiar and some unfamiliar, repeat the same experience—show transitions between the visible and the invisible.
Once more, let us ask what must be the original conception of wind. Consider the facts apart from hypothesis, and the implication which every breeze or gust carries with it is that of a power neither visible nor tangible. Nothing in early experiences yields the idea of air, as we are now familiar with it; and, indeed, probably most can recall the difficulty they once had in thinking of the surrounding medium as a material substance. The primitive man cannot regard it as a something which acts as do the things he sees and handles. Into this seemingly-empty space around, there from time to time comes an invisible agent which bends the trees, drives along the leaves, disturbs the water, and which he feels moving his hair, fanning his cheek, and
