IF a comparison were instituted between the position of the modern astronomer and that of his prototype on the plains of Chaldea, it would not be altogether to the disadvantage of the ancient student of the heavens. He stood at the gateway of the unexplored Uranian mysteries, unfettered by the dogmatic theories of a line of predecessors. From his own imagination he constructed hypotheses and theories, with no feeling of uncertainty about the priority of invention, and with little anxiety concerning the agreement of theory and observation. The modern questions that distract the astronomical world had no place among the thoughts that disturbed the tranquillity of his soul. He had not reached that critical epoch when he must choose between the “old” and the “new” astronomy; and he was free from the harassing perplexity that besets the luckless astronomer of this age who seeks to learn the mysteries of the moon's motion, or strives to formulate the cause and the law of the variation in the terrestrial latitude. The iniquitous behaviour of the astronomical clock and level, combined with the possible, but unknown, influences of temperature, were not then in league to vex his waking hours and fill his dreams with illusory solutions that ever floated just beyond his grasp. He was not obliged to search the ancient records in musty volumes and strain the limits of conjecture in the interpretation of careless observations and imperfect memoranda; in short, he was a happy man, free to work in any direction, and not liable to be called upon from time to time to amuse or to instruct his fellows, or even to weary them, with prosy discourse on his own work or a stale résumé of astronomical progress.