The thousands of questions on which Astronomy has thrown its dazzling light belong to two entirely distinct categories; some offered themselves naturally to the mind, and man had only to seek the means for solving them; others, according to the beautiful expression of Pliny, were enveloped in the majesty of nature! When Bailly lays down in his book these two kinds of problems, it is with the firmness, the depth, of a consummate astronomer; and when he shows their importance, their immensity, it is always with the talent of a writer of the highest order; it is sometimes with a bewitching eloquence. If in the beautiful work we are alluding to, Astronomy unavoidably assigns to man an imperceptible place in the material world, she assigns him, on the other hand, a vast share in the intellectual world. The writings which, supported by the invincible deductions of science, thus elevate man in his own eyes, will find grateful readers in all climes and times. In 1775, Bailly sent the first volume of his history to Voltaire. In thanking him for his present, the illustrious old man addressed to the author one of those letters that he alone could write, in which flattering and enlivening sentences were combined without effort with high reasoning powers. "I have many thanks to return you, (said the Patriarch of Ferney,) for having on the same day received a large book on medicine and yours, while I was still ill; I have not opened the first, I have already read the second almost entirely, and feel better." Voltaire, indeed, had read Bailly's work pen in hand, and he proposed to the illustrious astronomer some queries, which proved both his infinite perspicacity, and wonderful variety of knowledge. Bailly then felt the necessity of developing some ideas which in his _History of Ancient Astronomy_ were only accessories to his principal subject. This was the object of the volume that he published in 1776, under the title of _Letters on the Origin of the Sciences and of the People of Asia, addressed to M. de Voltaire_. The author modestly announced that "to lead the reader by the interest of the style to the interest of the question discussed," he would place at the head of his work three letters from the author of _Merope_, and he protested against the idea that he had been induced to play with paradoxes. According to Bailly, the present nations of Asia are heirs of an anterior people, who understood Astronomy perfectly. Those Chinese, those Hindoos, so renowned for their learning, would thus have been mere depositaries; we should have to deprive them of the title of inventors. Certain astronomical facts, found in the annals of those southern nations, appear to have belonged to a higher latitude. By these means we discover the true site on the globe of the primitive people, proving against the received opinion that learning came southward from the north.