Dr. Child says, "Among all the sights the eye can look upon, nothing is comparable to the Heavens for the sentiment with which they charm the mind. The language they speak comes to us from remote mysterious worlds; but, though it may be imperfectly understood, it is at least universally felt. The great and the small--the civilized man and the savage, the philosopher, the divine, and the illiterate or humble citizen--all feel their influence, and are from time to time irresistibly drawn toward them by mingled emotions of admiration, gratitude and awe, such as none of the other features of nature can excite in an equal degree. "So strongly, however, is the idea of the 'incomprehensible' associated by many with the mysteries of the firmament, that they are habitually prone to regard the teachings of astronomers as little else than scientific guess-work. Nevertheless, the best intellects in all countries assure us, and demonstrate before our eyes, that, within certain limits, Astronomy is the most exact and perfect of sciences, and that, even when it deals with distances and magnitudes, which are practically inconceivable, its conclusions, though often claiming to be approximative only, have yet no affinity whatever with guess-work. Let such sceptics think of the certainty with which sidereal events are predicted beforehand. Let them reflect on the evidence of the most exact knowledge of the heavenly bodies involved in the calculation of eclipses, in fixing the very moment when the moon's dark outline shall begin to creep over the sun's bright disk; marking its progress to the highest maximum, and its waning--giving the moment when the last visible shadow will disappear--predicting the instant when a planet's light shall be extinguished behind our satellite. And yet even more wonderful, the tracking of a comet's wanderings, millions of miles beyond the far-off regions of Uranus, the foretelling the time of its return after long years of absence! Do not these, and a thousand other equally wonderful feats, attest both the soundness of the principles on which the astronomer works, and the reasonableness of receiving his assurances with confidence and trust, even though it may be impossible for more than a few gifted minds to follow the calculations on which they are based?"