Phosphorescence of the Sea 533 



only met amongst animals of the four last classes of modern naturalists, 

 viz., mollusca, insects, worms, and zoophytes. 



Macartney recognized the true cause of the light, although he 

 had little idea of the vast number of marine forms which are lumi- 

 nous and omits entirely any reference to the fishes, many of w^hich 

 produce a light of their own when living, apart from bacterial infec- 

 tion when dead. He also omitted the " infusoria." 



Wilhelm Gottlieb Tilesius von Tilenau's (1769-1857) observa- 

 tions were published in part in volume 4 of Krusenstern's Reise and 

 in part arranged by L. W. Gilbert in the Atinalen der Physik for 

 1819, a volume largely devoted to sea phosphorescence. There were 

 two microscopes on the ship during its voyage around the world in 

 1803-1806. Tilesius observed animals such as mollusca, Crustacea, 

 nereidae, medusae, pyrosomae, salpae, zoophytes, and infusoria to be 

 present in displays of phosphorescence and responsible for the bright 

 specks, balls, fiery streaks, and chains of light. The weaker, more 

 general luminescence he considered due to animals also, perhaps 

 spawn, as Tilesius could not imagine what else the light might come 

 from. There w^as no doubt in Tilesius's mind as to the biological 

 origin of this phenomenon. After Macartney (1810) and Tilesius 

 (1819) , innumerable writers ascribed the light of the sea to living 

 things and described the animals involved, largely as a result of some 

 sea journey. 



Sea Light and the Weather 



It was an early observation that the sea " burned most " w-hen the 

 wind w^as from a certain direction. The relation of sea light to the 

 weather is of course directly connected with the growth of living 

 organisms, particularly the dinoflagellates described in the next sec- 

 tion. The long spell of hot and calm weather which precedes a storm 

 is particularly favorable for their grow^th. A number of observers 

 have commented on this relation, among them John Murray (1826) . 

 He did not describe minute organisms, but he did observe larger 

 animals, and wrote (1826: 84) : " It seems quite certain, therefore, 

 that the luminosity of the sea is a phenomenon dependent on the 

 presence of luminous marine animals." He w-as particularly struck 

 with the fact that unusual brilliant displays of sea light preceded 

 gales. To quote again (1826: 78) : " I believe / 7nay claim for myself 

 the priority of brilliance or appearance on the coast, as connected 

 with this new metereological feature— the coming storm." 



C. Decharme (1869) also, from observations near St. Nazaire held 

 that phosphorescence of the sea came after hot w^eather and before 



