THE NIGHT-LIGHTS OF THE SEA. 11 



of the diffused phosphorescence of the sea. The 

 myriads of animalcules give to the ocean the appear- 

 ance of a universal effulgence. But other animals 

 are solitarily phosphorescent. Jelly-fishes, and their 

 neighbours, the " Venus's girdles," show such a light. 

 Some fishes also possess phosphorescent qualities ; 

 and, as regards insects, our familiar glow-worm has 

 only to be named to call to mind an analogous 

 example of light-producing powers. The why and 

 wherefore of the phosphorescence lies in a nutshell. 



You have only to hark back to a great and leading 

 principle in science to find the clue to the mystery. 

 That one force of Nature can be transformed into 

 an equivalent of another force, is plain language of 

 science. Fire a bullet at a target. When the bullet 

 hits the mark its motion has become transformed into 

 an equivalent of heat. Similarly out of motion you 

 may get electricity, and out of electrical motion of 

 another kind you may get light. So is it with life 

 and living structures. So much of vitality, or 

 life-force, goes to produce motion, and so much in 

 particular cases (that of our Noctiluca included) to 

 produce light. Just as by the discharge of its 

 nerve-force into its electrical organ, a species of 

 skate produces electricity, and gives you a powerful 

 shock ; so your animalcule, transforming a modicum 

 of its life-force in a special fashion, gives you " the 

 night-light of the sea." 



But it is time to draw rein to these thoughts. 

 Here is the lightship close on our starboard bow. 

 "To rest we repair," as the old song has it; yet the 

 animalcules will not cease their phosphorescence, even 

 when the faint rays of the morning have brightened 

 " more and more into the perfect day." 



