"Felix qui potuit rerum cognoscere causas!" So Virgil sings; life has no purer joy. Yet whosoever was this first, the lips of history are mute. Some king's "magician," or soothsayer of the Nile, perhaps; no mighty cenotaphs immortalise his name; not for such as he do a hundred thousand burdened slaves sweat and grunt through thirty years to rear a tomb. For that matter, there may have been no one. Great conceptions, great discoveries, have no Minervan birth. So, here and there among the old Greeks, we find men who seem to have caught sight of the idea, but did not "see it clearly and see it whole." Thus old Hicetas of Syracuse, or Nicetas, as Cicero calls him-Cicero's account, doubtless, was not very accurate, for Cicero was a literary man; it may quite misrepresent. But Hicetas, he says, pictured the earth as "turning and twisting on its axis while all else in the heavens stands still." Quaint and ingenious thought. In another century a great Alexandrian will take out the twist, and thus, away back there, work out in all its essentials our modern welt-anschauung. But the proposal to give the earth not only a rotatory but a translatory motion as well, drove against a simple but very formidable obstacle. That was the dislocation which two bodies our two peaks from the Matterhorn, for exampleseem to undergo when we change our point of view. If the sun be at an enormous distance from the earth, and the earth goes round it, then from one side of the circle to the other we shall view the stars from two enormously separated points. Some of the stars must appear to shift their position one to another if this be true. No one could find the slightest change in the stellar sphere. Alone the sun and planets moved. True if one could think, with Eudoxus, that the stars were set in the face of a solid sphere, so all would be at an equal distance, there would be no difficulty. But it was clear that the planets were widely ranged in space; the eclipses left no doubt of that; their brilliancy suggested the same. There was the same varied brilliance among the unmoving stars; they differed from the almost planet's glow of Sirius and Arcturus to the faintest gleams. There was one escape, and one alone. That was to conceive the fixed stars as so remote from all mundane relations that, compared with this, even the distance of the sun was as nothing. But so doing seemed to loose the earth from its moorings, and toss it like a fragile bark upon the wastes of a boundless sea. It was to view the sun and earth and its vast orbit as but a point in the unending marches of the sky. Lost in such reverie. of the infinite, the imagination reels in drunken sublimity; the ways of space became a welter of whirling specks; the aimless motions of a cloud of insects, the image of the handiwork of God. Staled by custom, by constant iteration, we have become a little steadied to the view. But to what somnambulist of space did it come first? Is there any mind in Hellas to rise to such an outlook on the world? What said Aristarchus ? THE human mind has been young; it was poor, but it has become rich; it was ignorant of what it now knows. Ideas have been successively gathered together, heaped up; they have mutually engendered each other, the one has led to another. It remains therefore merely to rediscover this succession, to begin with the earliest ideas; the path is traced out; it is a journey that one may make again because it has already been made; the individual may now cover in the course of some hours' reading an extent of knowledge which it has cost the race long centuries to acquire. BAILLY, Histoire de l'Astronomie Moderne. |