Pausanias, Description of Greece 9. 39. 3 :
“[Part of the rituals at the oracle of Trophonios at Lebadeia, Boiotia :] He [the supplicant] is taken by the priests, not at once to the oracle, but to fountains of water very near to each other. Here he must drink water called the water of Lethe (Forgetfulness), that he may forget all that he has been thinking of hitherto, and afterwards he drinks of another water, the water of Mnemosyne (Memory), which causes him to remember what he sees after his descent . . . After his ascent from [the oracle of] Trophonios the inquirer is again taken in hand by the priests, who set him upon a chair called the chair of Mnemosyne (Memory), which stands not far from the shrine, and they ask of him, when seated there, all he has seen or learned. After gaining this information they then entrust him to his relatives. These lift him, paralysed with terror and unconscious both of himself and of his surroundings, and carry him to the building where he lodged before with Tykhe (Fortune) and the Daimon Agathon (Good Spirit). Afterwards, however, he will recover all his faculties, and the power to laugh will return to him.”