single human life, that we are all apt to be a little drunk with our own success. And yet that progress has been marked by incidents which should make us sober. The field, though a small one, on which its victories have been achieved, is strewn with the bodies of the slain. Dead theories and abandoned speculations lie thick upon the ground, while some of the most mischievous preconceptions still encumber the progress of inquiry. One of the first great general conceptions which lifted the speculations of mere cosmogony to the dignity of a science, was the Huttonian theory. One part of it was securely true. Another part of it was profoundly false. It was true as regards the continuity of causes. It was also as regards the uniformity of their effects. It was true that the rocks have been built up by the interaction of the forces of elevation, and the forces of degradation and depression. It was true that the causes which heaved the hills, have been ever met and checked by causes which wore them down again. But it was not true that the operation of higher laws is never indicated, or that all we can ascertain is limited to a perpetual seesaw of monotonous repetition. As usual, there were many minds which valued the Huttonian theory not for its truths, but mainly for its deficiencies and errors. The school of thought that delights to shut out those fountains of power from which all thought has come, were enchanted with a conception which reduced creation to the dull rounds of mechanical necessity. It was enthusiastic over the famous formula that geology saw "no trace of a beginning, no symptom of an end." In this form it may be called the great hurdy-gurdy theory. Then came the discovery of a clew by which an order of succession could be established in time, and, with time, in the perpetual introduction of new forms of life. Of course the mechanists set to work again, and they are at work still. Lyell supplied them with the only philosophical basis on which they can stand at all, and preached the doctrines of uniformity with immense knowledge and with infinite skill. As in the previous case of the theory of Hutton and of Play fair, much of what he taught was true, while the errors and exaggerations of his teachings are now being gradually but surely left behind. "The bit-by-bit theory of our friend Lyell will never account for all our facts," was the observation made to me one day by Lyell's compatriot, friend, and equal, Sir Roderick Murchison. On this subject happily there is no need of controversy with Prof. Huxley. He has himself taken a creditable part in checking extreme opinions and in showing that the doctrine of uniformity, in the only sense in which it can be rationally held, is quite consistent with any amount of catastrophe and convulsion. In fact, the recur-
- Theory of the Earth, by James Hutton, M. D., 1795.