Page:Popular Science Monthly Volume 13.djvu/401



UT there was still a long road to travel, before even the threshold of the temple of truth was reached. Nothing is better fitted to humble the spirit of speculation, which is ever and again lifting its head in Germany, than a contemplation of the first faltering steps of natural science, after it had at last been aroused from its slumber. If speculation were of any avail, one might suppose that it would succeed, above all, in throwing light upon a subject so comparatively accessible to our understanding as the laws of motion. But as Kant in later times failed to discover a priori the conservation of energy, so did the foremost minds of the Renaissance fail to find a priori the simplest truths of mechanics—truths since so transformed, if the expression be allowed, into flesh and blood of civilized man, that nativists might be tempted to regard them as innate. To us it appears inconceivable that once it required the profoundest meditation to discover the first law of motion, the inertia, as it is called, of matter, in virtue of which the motion of a body does not change without an external cause; that, down to the period of which we are speaking, no one had acquired a clear notion as to why a rolling ball at last stands still. Galilei even at first believed that a body, water, for instance, may move in a circle, without being