Empedocles offered these secrets to prospective disciples: "What drugs there are for ills and what help against old age you will learn, since for you alone I shall accomplish all this. And you will stop the power of the tireless winds which sweep over the earth and destroy the crops with their breath, and again, if you wish, you will bring on compensating breezes. And after black rain you will produce a seasonable drought for men, and after the summer drought you will produce tree-nurturing streams which live in the ether. And you will lead frorm Hades the power of dead men."

Source J Barnes, The Presocratic Philosophers, volume 2 (London Routledge & Kegan Paul, 1979)