16 M. (le Quatrefages on the Phosphorescence of 



loped by the force of opposing currents or by the prows of ves- 

 sels. Other authors have attributed it to phosphoric fires, to 

 the burning of bubbles of hydrogen which rise to the surface to 

 explode, &c. The opinion published by Tingry is of a similar 

 nature. This philosopher regards the phosphorescence of the 

 sea as analogous to that which certain bodies, the diamond in 

 particular, present, after having been awhile exposed to the sun. 

 Without entirely setting aside the agency of animals, he attri- 

 butes the greater part of the phsenomenon to a sort of previous 

 imbibition of the sun^s rays, which are thrown out again during 

 the night. He thus explains entirely by physical causes the 

 remarkable intensity of this phosphorescence in tropical seas*. 



A more rational if not a more correct explanation, at least for 

 many cases, is that which attributes the phosphorescence of the 

 sea to the decomposition of fishes and other marine animals. 

 This opinion was adopted by Commerson in his manuscripts 

 which are deposited in the library of the Museum. 



A passage very much to the point is quoted by Lesson from 

 one of his manuscripts t : " Phosphorescence is owing to a ge- 

 neral cause, that of the decomposition of animal substances, espe- 

 cially of whales and seals, which abound in oily matters.^^ Bory 

 de St. Vincent, Oken, and others have adopted the same view. 

 There is certainly great appearance of probability in this expla- 

 nation ; it is sustained by well-known facts, and sufficiently ac- 

 counts for certain circumstances of the phsenomenon. Still, in 

 many cases it is scarcely better founded than the preceding. 

 The same appears to have been the opinion of Newland, and of 

 those who like him have attributed phosphorescence to the 

 spawn of fishes. 



But, since the beginning of the last century, careful observa- 

 tions have been made ; and various observers have found that a 

 great number of sea animals have the property of directly emit- 

 ting this light. Since 1805, Viviani, professor of natural history 

 at Genoa, has discovered in the neighbourhood of that city, and 

 described in a work on the subject, fourteen species of phospho- 

 rescent animals J. 



Many travellers have noticed the phosphorescent properties of 

 the Medusae. Spallanzani, by diffusing in milk the mucus from 

 their bodies, rendered the liquid luminous §. Vianelli attributed 



* De la phosphorescence des corps, et particuUerement de celle des eaux 

 de la mer (Journal de Physique, t. xlvii.). 



t Diet, des Sc. Nat., ai-ticle Phosphorescence. 



X Phosphorescentia . maris quatuordecim lucescentium aniraalculorum 

 novis speciebus illustrata. Genuaj, 1807. 



§ Voyage en Sicile. 



