58 



small balustrade of reeds, which extends along 

 the road leading to the upper bridge. 



Sixty feet below this natural bridge is another, 

 to which we are led by a narrow pathway, which 

 descends upon the brink of the crevice. Three 

 enormous masses of rock are fallen so as to 

 support each other. That in the middle forms 

 the key of the arch ; an accident which might 

 have given the natives the idea of arches in 

 masonry, unknown to the people of the new 

 world, as well as to the ancient inhabitants of 

 Egypt. I shall not decide the question whether 

 these masses of rock have been projected from a 

 great distance, or whether they are the frag- 

 ments of an arch broken on the spot, but origi- 

 nally like the upper natural bridge. The latter 

 conjecture seems probable, from a similar event 

 which happened to the Coliseum at Rome, 

 where, in a half ruined wall, several stones were 

 stopped in their descent, because in falling 

 they accidentally formed an arch. 



In the middle of the second bridge of Ico- 

 nonzo is a hollow of more than eight metres 

 square, through which the bottom of the abyss is 

 perceived. We there made our experiments on 

 the fall of bodies. The torrent seems to flow 

 through a dark cavern, whence arises a lugubri- 

 ous noise, caused by the numberless flights of 

 nocturnal birds that haunt the crevice, and 



