It is an unquestionable fact that the human mind has been in all ages disposed to accept a number of narratives of supernatural occurrences upon very insufficient testimony, and which the principles of sound reason lead us to reject as untrue. Such beliefs have been peculiar to no one period of the world’s history, but have been co‐extensive with the human race; and they form one of the most remarkable facts in our nature. Many of the ancient historians have reported such occurrences without apparent suspicion; or if they entertained any doubts respecting their truth, they did not venture even to whisper them into the popular ear. What is still more; eminent men of the ancient world did not scruple to act in matters of this kind a part which they knew to be deceptive, because they held the opinion that such beliefs, though they might be laughed at by philosophers, were necessary to act as restraints on the vulgar. Thus we know, on the most indubitable authority, that a Roman Augur could gravely act his part before the public at the very time that he was secretly laughing in his sleeve at the ridiculousness of his art. It does not therefore follow because the ancient historians have reported numbers of occurrences of this nature with considerable gravity, that they accepted them as facts. They were frequently influenced by the spirit of accommodation, thinking it necessary for the welfare of society to keep up the vulgar ideas on the subject. It would be inaccurate therefore to attribute all the accounts of such things which we meet with in ancient writers to simple credulity, or to infer from them that they did not believe in an inviolable order of nature of some kind. With respect to the arts of magic, however, one feels that even the greatest of the ancient writers contemplated them with a kind of bated breath. This would appear to have been the state of mind even of Tacitus, with one exception the greatest historian of the ancient world, and one who was intimately acquainted with the various systems of its philosophy. Conscious as he was that vast numbers of the professors of magic were impostors, he seems hardly able to realize the fact that the whole art was a delusion.