PEEFACE. 



r I iHE object of the present work is to interest young people in 

 -*- natural history by the presentation of an attractive — indeed, 

 marvellous — phase of nature, and to encourage healthful outdoor 

 observation, as well as habits of investigation. 



The subject chosen for this work — that embracing the phe- 

 nomenon of luminosity in animals, plants, and inorganic matter, 

 and especially those that seem intended as illuminators of the ocean 

 — is one which has ever possessed a fascination for the author. 



During many years spent on Southern shores, in constant asso- 

 ciation with the most attractive features of marine life, the remem- 

 brance of the splendors of the night festivals of these wondrous 

 ocean forms is most enduring. No fairy tale of human invention 

 can relate to us more fascinating scenes than are realized in Nature's 

 carnivals of the sea. Not only is the surface of the ocean, when 

 lashed into foam by the tempest, luminous, but the greater depths, 

 where the water is cold, near the freezing-point, and subject to 

 pressure so great that instruments of glass are shattered and 

 reduced to powder, abound in living lights. 



And this abyssal region, covered by miles in depth of water, and 

 which was formerly considered to be the most desolate region upon 

 the globe, is inhabited by light-givers of marvellous beauty and 

 brilliancy. 



The little Malacosteus, with its gleams of yellow and green ; 

 Stomias, with sparkling side-lights ; the dazzling effulgence of 

 Pyrosoma; the comet-like glare of Medusae, with their tints of 



