"M. Otto Struve, Mr. Bond and Sir David Brewster are agreed that Saturn's third ring is fluid, that it is gradually approaching the body of Saturn, and that we may expect, sooner or later, to see it united with the body of the planet. With this deluge impending, Saturn would scarcely be a very eligible residence for men whatever it might be for dolphins." (_See Annual of Scientific Discovery, 1856, p_. 377.) Let the skeptic show that God did not, or could not suspend a similar celestial ocean over the earth, or cease to pronounce a universal deluge impossible. Again, it may be asked. Has the moon an atmosphere? Are the atmospheres of the planets like ours? What is the cause of the light and heat of the sun? These and many other questions scientists variously answer, but leave unanswered after all. Comets constitute by far the greatest number of the bodies of our solar system. Arago says seven millions frequent it, within the orbit of Uranus. They are the largest bodies known to us, stretching across hundreds of millions of miles. {155} [ILLUSTRATION: THE COMET OF 1811.] They approach nearer to this earth than any other bodies, sometimes even involving it in their tails, and generally exciting great alarm among its inhabitants. But the nature of the transparent, luminous matter of which they are composed is utterly unknown. While their density was doubtful, they formed very convenient material for the atheist's world-factory; but recently they have been literally dissipated into smoke by powerful telescopes. In fact a respectable wreath of smoke is quite substantial compared with the densest of the comets. Stars of the smallest magnitude remain distinctly visible though covered by what appears to be their densest portion; although these same stars would be completely obscured by a moderate fog extending only a few yards above the {156} earth. Neither are they dense enough to cast a shadow. It is thus evident that the most substantial clouds which float in our atmosphere are dense and massy bodies compared with the filmy and all but spiritual texture of a comet's tail. Neither do men understand the laws that govern the motion of comets. As they approach the sun, they come under an influence directly the opposite of attraction. While the body of the comet travels towards the sun, sometimes with a velocity nearly one-third of that of light, the tail shoots forth in the opposite direction with much greater velocity. The greatest velocity with which we are acquainted on earth is the velocity of light, which travels a million times faster than a cannon ball, or at the rate of 195,000 miles per second. [ILLUSTRATION: COMET PASSING ROUND THE SUN (ITS PERIHELION).]