These stars occur both at sea and at land. I have seen, during the night-watches of the soldiers, a luminous appearance, like a star, attached to the javelins on the ramparts. They also settle on the yard-arms and other parts of ships while sailing, producing a kind of vocal sound, like that of birds flitting about. When they occur singly they are mischievous, so as even to sink the vessels, and if they strike on the lower part of the keel, setting them on fire[2]. When there are two of them they are considered auspicious, and are thought to predict a prosperous voyage, as it is said that they drive away that dreadful and terrific meteor named Helena. On this account their efficacy is ascribed to Castor and Pollux, and they are invoked as gods. They also occasionally shine round the heads of men in the evening[3], which is considered as predicting something very important. But there is great uncertainty respecting the cause of all these things, and they are concealed in the majesty of nature.