92 LETTERS ON NATURAL MAGIC. 



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 philo- 

 sophers 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 sub- 

 sequent 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 con- 

 firmation from the mechanical arrangements which seem 

 to have formed a part of their religious impostures. 

 When in some of the infamous mysteries of ancient Eome, 

 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 Leavings of the waves. The rapid descent 

 of those who consulted the oracle in the cave of Tro- 

 phonius, 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. 



But of all the sciences Optics is the most fertile in 

 marvellous expedients. The power of bringing the re- 

 motest objects within the very grasp of the observer, and 

 of swelling into gigantic magnitude the almost invisible 



