History is the action and reaction of these two,--Nature and Thought,--two boys pushing each other on the curbstone of the pavement. Everything is pusher or pushed: and matter and mind are in perpetual tilt and balance so. Whilst the man is weak, the earth takes him up. He plants his brain and affections. By-and-by he will take up the earth, and have his gardens and vineyards in the beautiful order and productiveness of his thought. Every solid in the universe is ready to become fluid on the approach of the mind, and the power to flux it is the measure of the mind. If the wall remain adamant, it accuses the want of thought. To a subtler force, it will stream into new forms, expressive of the character of the mind. What is the city in which we sit here, but an aggregate of incongruous materials, which have obeyed the will of some man? The granite was reluctant, but his hands were stronger, and it came. Iron was deep in the ground, and well combined with stone, but could not hide from his fires. Wood, lime, stuffs, fruits, gums, were dispersed over the earth and sea, in vain. Here they are, within the reach of every man's day-labor--what he wants of them. The whole world is the flux of matter over the wires of thought to the poles or points where it would build. The races of men rise out of the ground preoccupied with a thought which rules them, and divided into parties ready armed and angry to fight for this metaphysical abstraction. The quality of the thought differences the Egyptian and the Roman, the Austrian and the American. The men who come on the stage at one period are all found to be related to each other. Certain ideas are in the air. We are all impressionable, for we are made of them; all impressionable, but some more than others, and these first express them. This explains the curious contemporaneousness of inventions and discoveries. The truth is in the air, and the most impressionable brain will announce it first, but all will announce it a few minutes later. So women, as most susceptible, are the best index of the coming hour. So the great man, that is, the man most imbued with the spirit of the time, is the impressionable man--of a fibre irritable and delicate, like iodine to light. He feels the infinitesimal attractions. His mind is righter than others, because he yields to a current so feeble as can be felt only by a needle delicately poised.