Classical study and literature are regarded as so important in education, and a knowledge of Greek mythology is so obviously necessary to a full understanding of the best Greek authors, that many works have been published on the subject. The writers have either merely stated the fables as reported among the ancients, or in addition have sought to trace them to their origin, either by making conjectures of allegorical, historical and physical meanings in the stories, or deriving them from the events of the early ages, recorded in the Bible. But as these traditions themselves arose in various ways, and often accidentally, there of course must be error in every system which attempts to refer them to a common cause and purpose. The foundation of very many of the fictions of mythology is laid in ideas that arose from the simplicity and inexperience of persons conversant only with objects of sense. Wherever an unusual fact or appearance was observed it was ascribed to a distinct being or existence, operating directly or immediately. This creation by them of personal existences out of natural phenomena, this ever ready personification of physical objects and events, was, in all probability, one of the most fruitful sources of fable and of idolatry, for which the stars and the elements seem to have furnished the most common occasion. “One source of fable,” says an able writer, “is the _perversion_ or _alteration of facts_ in sacred history; and indeed this is its earliest and principal source. The family of Noah, perfectly instructed by him in religious matters, preserved for a considerable time the worship of the true God in all its purity. But when the members of this family were separated and scattered over different countries, diversity of language and abode was soon followed by a change of worship. Truth, which had hitherto been intrusted to the single channel of oral communication, subject to a thousand variations, and which had not yet become fixed by the use of writing, that surer guardian of facts, became obscured by an infinite number of fables which greatly increased the darkness that had enveloped it.” The advantages of an acquaintance with mythology are many. They have been admirably shown by Rollin, from whom we quote: