Light and sound are the daughters of motion. Color and music, the ethereal and aerial offspring of this ancestry, born with the world, fostered in Biblical times, expanded in China and Egypt, living on the painted jar, and breathing in the oaten reed, deified in Greece, and analyzed to-day, are natural cousins at the least, and they have come from the spacious home of their progenitor, upon our dusky and silent sphere, like Peace and Goodwill, with hands bound in an oath and contract never to part. We will spare a dissertation on chaos; we will not speak of matter and inertia; but as our greatest and purest fountain of light is the sun, we may be allowed a modest exposition of his philosophical state, as a granite gate to the garden beyond. Ninety-five millions of miles to the north, east, south, or west of us, up or down, as the case may be, stands the molten centre of our system--an orb, whose atoms, turbulent with electricity, gravity, or whatever mechanists please to call the attraction of particle for particle, are forever urging to its centre, forever meeting with repulsions when they slide within the forbidden limits of molecular exclusiveness, and eternally vibrating with a quake and quiver which lights and heats the worlds around. In other words, this agitation is one that, transmitted to an ethereal medium, produces therein corresponding vibrations or waves, which are light and heat. As sound is the symmetrical aerial motion, if our atmosphere embraced our sun, and extended throughout space, we should _perhaps_ hear in the ambient the fundamental chord, resolvable into the diatonic scale--as we look upon the beam of white which the prism decomposes into the solar spectrum, and in the ghostly watches of the night, we might recognize the 'music of the spheres' as the planets rushed around their airy orbits, with a noise like the 'noise of many waters,' no longer a poetic illusion, but a harmonic fact. Light, whether white or colored, is transmitted through ether in waves of measurable length: each atom of the medium, when disturbed, moves around its place of rest in an orbit of variable dimension and eccentricity. On the character of the orbit depends the character of the light; and on the velocity of orbit motion, its intensity. Like the gentle pulsations which circle from the point where fell the pebble in the purple lake, come the grateful twilight waves, red with the last kiss of day; like the fierce struggles of the storm-beaten ocean floods come the lightning waves, blazing through the thunder clouds, howling in riven agony: so great is the variety of character in these orbicular disturbances, which, acting upon the optic nerves, produce the sensation of multiform light and color. Waves of light, like waves of sound, are of different lengths, and while the eye prefers some single waves to others, it recognizes a harmony in certain combinations, which it cannot discover in different ones.