172 PHOSPHORESCENCE. 



We thus become impressed with the generality 

 of these phenomena, which have hitherto been re- 

 garded only as rare and mysterious evolutions of 

 light. 



It is curious to note the progress of the dis- 

 covery of phosphoric phenomena, and the in- 

 effectual attempts that have been made to explain 

 them as our knowledge gradually extended. 



The ancient Greeks gave the name Phosphorus 

 to the morning star, or planet Venus, when it 

 rises before the sun. By the Latins, the name of 

 Lucifer was given to this star, which the French 

 term Etoile de Berger. 



Although the phosphorescence of the Bologna 

 stone, and certain other phosphori, was only ob- 

 served in the seventeenth century, the luminosity 

 of the sea was familiar to observers in the darkest 

 ages of antiquity. Some authors assert that it 

 was generally attributed by the ancients to Castor 

 and Pollux; but the phenomenon attributed to 

 these divinities was simply the electric light which 

 I have alluded to as the Fire of St. Elmo, appear- 

 ing in stormy weather on the masts of ships. 



Aristotle mentions light proceeding from pu- 

 trescent substances and from glowworms; Pliny 

 was acquainted with the luminous properties of 

 the dead Pholas and certain Medusa, and this 

 ancient naturalist knew that by rubbing one of 

 these animals upon a plank the wood became 



