THE ARCHIPELAGO OF BREHAT. 129 



a fixed light is maintained in a lighthouse of the first 

 order. I think some explanation will be necessary 

 here to make you understand the destination and 

 effect of the different parts of an instrument, in 

 which, at first sight, you perceive nothing more than 

 a kind of huge glass barrel, whose hoops are repre- 

 sented by prisms of the same substance, and which 

 is furnished, both above and below, with a row 

 of shades or screens, composed of several series of 

 inclined mirrors. 



The ancients, who were much more addicted to 

 navigation than is usually supposed to have been the 

 case, seem to have recognised from the remotest 

 antiquity the necessity of maintaining signals, which 

 might indicate to the navigator the dangers to be 

 avoided in his course, and the channels by which 

 he might safely steer his small craft, which was 

 adapted only for coasting voyages. From the Black 

 Sea to the Ocean, almost every promontory was sur- 

 mounted by an altar, column, or tower, from whence 

 clouds of smoke issued by day, while its fires guided 

 the seamen during the darkness of night. Almost 

 all these ancient Phari were at the same time temples 

 consecrated to some divinity, whose name they bore. 

 The priests who tended them, were the astronomers 

 of those remote ages, who instructed the seaman how 

 to steer his way along the neighbouring shores. Some 

 antiquarians of our own day have believed that this 

 circumstance furnished an explanation of many 

 mythological fables. Thus in their eyes, the god 

 Proteus, who was consulted by Mcnelaus on his 

 return from the Trojan war, is only one of these 



VOL. I. K 



