THE USES OF PHOSPHORESCENCE. 163 



ing with phosphorescent animals, redounds to the benefit of 

 the fishermen. The pale phosphoric cloud, seen from the top 

 masthead, resting upon the surface of the ocean, tells the 

 secret of their exact situation ; and, by surrounding it with 

 the great net, large schools are often caught. t 



Among the insects we have definite experiments to show 

 that the light they emit is a signal; in other words, the 

 insects recognize the lights of their friends. A French nat- 

 uralist one evening held from his window a living specimen of 

 Lampyris noctiluca (Plate IX.) in the presence of several 

 friends ; and a few moments later a companion insect left the 

 gleaming throng without, and alighted upon his hand, touch- 

 ing the captive, whose light was almost immediately extin- 

 guished. 



M. Raphael Dubois, member of the Zoological Society of 

 France, etc., has shown that the Pyrophorus (Plate XL) 

 uses its light as we would a lantern in the night. When he 

 covered the light upon one side of the insect, it pursued a 

 curved course ; and, when both lights were extinguished, it 

 was obviously at fault, and moved along with great care, and 

 was evidently unfitted for nocturnal life. 



We have seen how these insects were the means of saving 

 the life of Jaeger, in lighting him out of the forests of the 

 southern islands ; how natives attach them to their feet, and 

 employ them as lanterns ; while others in South America form 

 an article of trade, being utilized by the ladies as articles of 

 personal adornment. 



It must be evident to my young readers, that a practical 

 application of the general features of phosphorescence would 

 be extremely valuable, and in the previous chapter luminous 

 paints and writing fluids have been referred to. An English 



