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 tion that we may discern somewhat of the beginning, or of the end, of this speck in space we call our earth. The finite mind is certainly competent to trace out the development of the fowl within the egg ; and I know not on what ground it should find more difficulty in unravelling the complexities of the development of the earth. In fact, as Kant has well remarked*, the cosmical process is really simpler than the biological.

This attempt to limit at a particular point the progress of inductive and deductive reasoning from the things which are to those which were — this faithlessness to its own logic, seems to me to have cost Uniformitarianism the place, as the permanent form of geological speculation, which it might otherwise have held.

It remains that I should place before you what I understand to be the third phase of geological speculation — namely Evolutionism.

I shall not make what I have to say on this head clear unless I diverge, or seem to diverge, for a while from the direct path of my discourse, so far as to explain what I take to be the scope of geology itself. I conceive geology to be the history of the earth in precisely the same sense as biology is the history of living beings ; and I trust you will not think that I am overpowered by the influence of a dominant pursuit if I say that 1 trace a close analogy between these two histories.

If I study a living being, under what heads does the knowledge I obtain fall ? I can learn its structure, or what we call its Anatomy ; and its Development, or the series of changes which it passes through to acquire its complete structure. Then I find that the living being has certain powers resulting from its own activities, and the interaction of these with the activities of other things — the knowledge of which is Physiology. Beyond this the living being has a position in space and time, which is its Distribution. All these form the body of ascertainable facts which constitute the status quo of the living creature. But these facts have their causes ; and the ascertainment of these causes is the doctrine of AEtiology.

If we consider what is knowable about the earth, we shall find that such earth-knowledge — if I may so translate the word geology — falls into the same categories.

What is termed stratigraphical geology is neither more nor less than the anatomy of the earth ; and the history of the succession of the formations is the history of a succession of such anatomies, or corresponds with development, as distinct from generation. The internal heat of the earth, the elevation and depression of its crust, its belchings forth of vapours, ashes, and lava are its activities in as strict a sense, as are warmth and the movements and products of respiration the activities of an animal. The phenomena of

zu sagen, dass eher die Bildung aller Himmelskorper, die Ursache ihrer Bewegungen, kurzder Ursprung der ganzen gegenwartigen Verfassung des Weltbaues werden konnen eingeschen werden, ehe die Erzeugung eines einzigen Krauts oder einer Raupe aus mechanischen Grunden, deutlich und vollstandig kund werden wird."— Kant's ' Sammtliche Werke,' Bd. I. p. 220.
 * " Man darf es sich also nicht befremden lassen, wenn ich mich unterstehe