The science of _Acoustics_ furnished the ancient sorcerers with some of their best deceptions. The imitation of thunder in their subterranean temples could not fail to indicate the presence of a supernatural agent. The golden virgins whose ravishing voices resounded through the temple of Delphos;--the stone from the river Pactolus, whose trumpet notes scared the robber from the treasure which it guarded;--the speaking head which uttered its oracular responses at Lesbos; and the vocal statue of Memnon, which began at the break of day to accost the rising sun,--were all deceptions derived from science, and from a diligent observation of the phenomena of nature. The principles of _Hydrostatics_ were equally available in the work of deception. The marvellous fountain which Pliny describes in the island of Andros as discharging wine for seven days, and water during the rest of the year;--the spring of oil which broke out in Rome to welcome the return of Augustus from the Sicilian war,--the three empty urns which filled themselves with wine at the annual feast of Bacchus in the city of Elis,--the glass tomb of Belus which was full of oil, and which when once emptied by Xerxes could not again be filled,--the weeping-statues, and the perpetual lamps of the ancients,--were all the obvious effects of the equilibrium and pressure of fluids. Although we have no direct evidence that the philosophers of antiquity were skilled in _Mechanics_, yet there are indications of their knowledge by no means equivocal in the erection of the Egyptian obelisks, and in the transportation of huge masses of stone, and their subsequent elevation to great heights in their temples. The powers which they employed, and the mechanism by which they operated, have been studiously concealed, but their existence may be inferred from results otherwise inexplicable; and the inference derives additional confirmation from the mechanical arrangements which seemed to have formed a part of their religious impostures. When, in some of the infamous mysteries of ancient Rome, the unfortunate victims were carried off by the gods, there is reason to believe that they were hurried away by the power of machinery; and when Apollonius, conducted by the Indian sages to the temple of their god, felt the earth rising and falling beneath his feet, like the agitated sea, he was no doubt placed upon a moving floor capable of imitating the heavings of the waves. The rapid descent of those who consulted the oracle in the cave of Trophonius,--the moving tripods which Apollonius saw in the Indian temples,--the walking statues at Antium, and in the temple of Hierapolis,--and the wooden pigeon of Archytas, are specimens of the mechanical resources of the ancient magic.