is now more prevalent than ever, and which gradually communicates itself even to those who are ignorant of mathematics. It often happens that a single great man gives the tone to the whole age in which he lives; and we must not forget, that the individual who has the most legitimate claim to the glory of having introduced and established a new art of reasoning, was an excellent geometer.”[22] The philosopher to whom this improvement of the art of reasoning is ascribed, is evidently Descartes, whose claim is certainly much less legitimate than that of our own illustrious countryman; but the works of Bacon were not very extensively studied on the continent, at the time at which Fontenelle wrote; while especially in France, the splendid reputation of the great geometer, who shook, as much with his own wild hypothesis, as with the weight of his reasoning, the almost idolatrous worship of the God of the Schools, seemed to sweep before it the glory of every other reformer. The instance of Descartes, however, is a still more happy one than his ingenious countryman, who was himself a Cartesian, could have imagined it to be. It is, indeed, impossible to conceive a more striking example of that diffusive influence of the _general spirit of scientific inquiry_, which I wish to illustrate; since, in this instance, it survived the very system by which it was diffused; all that was sceptical in that mixed system of scepticism and dogmatism which constituted the philosophy of Descartes, having long continued, and even now continuing, to operate beneficially, when scarcely a doctrine of his particular philosophy retains its hold. You will not then, I trust, take for granted, that precise notions as to the objects of inquiry, in any science, even in the department of external physics, can be so absolutely without benefit to our plans of inquiry into mind, which must be pursued on the same principles, if it be pursued with any prospect of success; and I may, therefore, safely solicit your attention to a little farther elucidation of the two objects which we have in view, in general physical inquiry, whether it be relative to _matter_ or to _mind_.