The return of a comet is frequently announced with great certainty. This paragraph appeared in a newspaper: "On the whole, it may be considered as tolerably certain that the comet will become visible in every part of Europe about the latter end of August, or the beginning of September next. It will most probably be distinguishable by the naked eye, like a star of the first magnitude, but with a duller light than that of a planet, and surrounded with a pale nebulosity, which will slightly impair its splendor. On the night of the 7th of October the comet will approach the well-known constellation of the Great Bear; and between that and the 11th it will pass directly through the seven conspicuous stars of that constellation. Toward the close of November the comet will plunge among the rays of the sun and disappear, and not issue from them, on the other side, until the end of December. This prospectus of the movements of a body, invisible at the time, millions of miles away, is nearly as definite as the early advertisements of coaching between London and Edinburgh. Let us now place the observations of the eye alongside the anticipations of science, and we shall find that science has proved almost absolutely correct." Just think of the calculations, gentlemen, that were necessary; for, though a comet does not interfere with the course of a planet, a planet interferes very considerably with the course of a comet; so that, in their calculations, the astronomers had to recollect the track in which the comet would have to travel. Thinking of him as a way-worn traveler, we remember that he will have to go by Neptune's bright abode, and Neptune will be sure to give him a cup of tea; then he will journey on as far as Uranus, and put up for the night there; in the morning he will pay an early visit to Saturn, and he will stay there for breakfast; he will dine with Jupiter; by and by he will reach Mars, and there will be sure to be a row there; and he will be glad when he gets to Venus, and, of course, he will be detained by her charms. You will, therefore, very readily see, gentlemen, that the calculations as to the return of a comet are extremely difficult, and yet the astronomers do estimate the time to a nicety. This science is a very marvelous one, not only for what it reveals, but for the talent which it brings out, and the lessons it continually teaches us about the wonderful works of our great Father.