Here, however, a difficulty meets us. If the teaching of the Solar Mythologists be true, the Aryans, having a mythology, were already polytheists: much more, therefore, must the Italians have been polytheists from the beginning. I am sorry to say that I cannot meet this difficulty: I can only frankly warn the reader that it exists. But in an Introduction which professes to confine itself to myths and cults which are purely Italian, it is impossible to discuss Solar Mythology, for the simple reason that there is no such thing in existence as an Italian solar myth, or indeed Nature-myth of any kind. The only story which is seriously claimed as a Nature-myth is that of Hercules and Cacus. Cacus, a monster or giant, stole some cows from Hercules, and hid them in his cave. Hercules discovered them, according to some accounts, by the aid of Caca, the sister of Cacus, according to other accounts, by the lowing which the cows in the cave set up when Hercules went by with the rest of his oxen. Hercules forced his way into the cave, and, in spite of the fire and flames which Cacus spat at him, killed the monster with his club. Then Hercules, in commemoration of the discovery of his cattle, erected an altar to Jupiter the Discoverer (_Jupiter Inventor_). Now a similar story, it would appear, is to be found in the Vedas. Vritra, a three-headed snake, steals cows from Indra, who discovers them in a cave by their lowing, and kills Vritra with a club. And the Vaidic story must be a Nature-myth, because the Vedas expressly explain that the cows are clouds, the lowing is thunder, the club is the lightning, and Indra, on this occasion, the blue sky. But why is the interpretation given by the Vaidic philosophers to be accepted without examination, when we reject the teaching of the Stoics, who interpreted Rhea as matter, and Zeus, Posidon, and Hades as fire, water, and air respectively, in accordance with the Stoic philosophy of the universe? I submit it as a possibility, worth consideration at least, that we have here an ordinary folk-tale: the trick of using the bulls to make the cows reveal their hiding-place is like the trick in the folk-tale about the groom of Darius who caused his master's horse to neigh and so secured the Persian empire to Darius. The story may have been told of some clever fellow (not necessarily or probably of a god) in pro-ethnic Aryan times, or it may have been hit on by Hindoo and Italian story-tellers independently. Once invented, however, it was used by each of these two peoples in a characteristic manner. The learned Roman, whose object was to explain the origin of the customs, cults, institutions, &c., of Rome, seized on it as the obvious explanation of two facts which required explanation, viz., first, how the altar to Jupiter Inventor came into existence; and second, why the offering made in gratitude for the recovery of lost property, was an ox. The learned Hindoo, on the other hand, had the satisfaction of