Let us turn to some examples of the marvelous virtues of particular stones. The crystal wins favorable answers from the gods to prayers; kindles fire, if held over sticks, yet itself remains cold; as a ligature benefits kidney trouble. Sacrifices in which the adamant is employed win the favor of the gods; it is also called Lethaean because it makes one forget worries, or the milk-stone (_galactis_) because it renews the milk of sheep or goats when powdered in brine and sprinkled over them. Worn as an amulet it counteracts the evil eye and gains royal favor for its bearer. The agate is an agricultural amulet and should be attached to the plowman’s arm and the horns of the oxen. Other stones help vineyards, bring rain or avert hail and pests from the crops. _Lychnis_ prevents a pot from boiling on a fire and makes it boil when the fire is dead. The magnet was used by the witches Circe and Medea in their spells; an unchaste wife is unable to remain in the bed where this stone has been placed with an incantation. Other stones cure snake-bite and various diseases, serve as love-charms or aids in child-birth, or counteract incantations and enchantments. [Sidenote: Magic rites to gain powers of divination.] To make the gem _sideritis_ or _oreites_ utter vocal oracles the operator must abstain for three weeks from animal food, the public baths, and the marriage bed; he is then to wash and clothe the gem like an infant and employ various sacrifices, incantations, and illuminations. The gem _Liparaios_, known to the learned Magi of Assyria, when burnt on a bloodless altar with hymns to the Sun and Earth attracts snakes from their holes to the flame. Three youths robed in white and carrying two-edged swords should cut up the snake who comes nearest the fire into nine pieces, three for the Sun, three for the earth, three for the wise and prophetic maiden. These pieces are then to be cooked with wine, salt, and spices and eaten by those who wish to learn the language of birds and beasts. But further the gods must be invoked by their secret names and libations poured of milk, wine, oil, and honey. What is not eaten must be buried, and the participants in the feast are then to return home wearing chaplets but otherwise naked and speaking to no one whom they may meet. On their arrival home they are to sacrifice mixed spices. It will be recalled that Apollonius of Tyana and the Arabs also learned the language of the birds by eating snake-flesh. [Sidenote: Powers of gems compared with herbs.]