In the third book of Philostratus, the initial chapter contains an account of Hyphasis, a wonderful river which rises in a certain plain and is lost in unapproachable regions. That river represents magical knowledge, which is simple in its first principles but difficult to deduce accurately in respect of final consequences.[129] Philostratus tells us in this connection that marriages are not fruitful unless consecrated by the balsam of trees which grow on the banks of Hyphasis. The fish of this river are sacred to Venus; their crest is blue, the scales are of many colours and their tail is golden: they can raise the tail at will. In the river there is also an animal resembling a white worm, the stewing of which produces an inflammable oil that can be kept in glass only. The animal is reserved only for the king’s service, as it has power to overthrow walls. When the grease of it is exposed to the air it ignites, and there is then nothing in the whole world with which the flame can be extinguished. By the fish of the river Hyphasis, Apollonius signifies universal configuration which magnetic experiments have recently proved to be blue on one side, golden on that which is opposite and of many colours at the centre. The white worm is the Astral Light, which resolves into oil when condensed by a triple fire, and such oil is the universal medicine. It can only be contained by glass, this being a non-conductor for the Astral Light, its porousness being inappreciable. This secret is reserved to the king, which means an initiate of the first order, for it is truly concerned with a force by which cities can be destroyed. Some important secrets are here indicated with great clearness. In the next chapter Philostratus speaks of unicorns and says that the horn of these animals can be fashioned into drinking-cups which are a safeguard against all poisons. The single horn of the symbolical creature represents hierarchic unity, and hence Philostratus adds, on the authority of Damis, that the cups in question are also exclusive to kings. “Happy,” says Apollonius, “is he who is never intoxicated but in drinking out of such a goblet.”