under the intellectual courage and activity which this great revolution had inspired. Power, once awakened, cannot rest in one object. All the sciences partook of the new influences. The world of experimental philosophy was soon mapped out for posterity by the comprehensive and enterprising genius of Bacon, and the laws explained by which experiment could be dignified into experience.(2) But no sooner was the impulse given, than the same propensity was made manifest of looking at all things in the one point of view which chanced to be of predominant attraction. Our Gilbert, a man of genuine philosophical genius, had no sooner multiplied the facts of magnetism, and extended our knowledge concerning the property of magnetic bodies, but all things in heaven, and earth, and in the waters beneath the earth, were resolved into magnetic influences. Shortly after a new light was struck by Harriott and Descartes, with their contemporaries, or immediate predecessors, and the restoration of ancient geometry, aided by the modern invention of algebra, placed the science of mechanism on the philosophic throne. How widely this domination spread, and how long it continued, if, indeed, even now it can be said to have abdicated its pretensions, the reader need not be reminded. The sublime discoveries of Newton, and, together with these, his not less fruitful than wonderful application, of the higher mathesis to the movements of the celestial bodies, and to the laws of light, gave almost a religious sanction to the corpuscular system and mechanical theory. It became synonymous with philosophy itself. It was the sole portal at which truth was permitted to enter. The human body was treated of as an hydraulic machine, the operations of medicine were solved, and alas! even directed by reference partly to gravitation and the laws of motion, and partly by chemistry, which itself, however, as far as its theory was concerned, was but a branch of mechanics working exclusively by imaginary wedges, angles, and spheres. Should the reader chance to put his hand on the “Principles of Philosophy,” by La Forge, an immediate disciple of Descartes, he may see the phenomena of sleep solved in a copper-plate engraving, with all the figures into which the globules of the blood shaped themselves, and the results demonstrated by mathematical calculations. In short, from the time of Kepler(3) to that of Newton, and from Newton to Hartley, not only all things in external nature, but the subtlest mysteries of life and organization, and even of the intellect and moral being, were conjured within the magic circle of mathematical formulæ. And now a new light was struck by the discovery of electricity, and, in every sense of the word, both playful and serious, both for good and for evil, it may be affirmed to have electrified the whole frame of natural philosophy. Close on its heels followed the momentous discovery of the principal gases by Scheele