THE METEOBS OF THE SEA. 17 



observed on one of his coilecting-tours. He says, " While 

 sailing a little south of the Plata on one very dark night, 

 the sea presented a wonderful and most beautiful spectacle. 

 There was a fresh breeze, and every part of the surface wliich 

 during the day is seen as foam now glowed with a pale light. 

 The vessel drove before her bows two billows of liquid phos- 

 phorus, and in her wake she was followed by a milky train. 

 As far as the eye reached, the crest of every wave was bright ; 

 and the sky above the horizon, from the reflected glare of 

 these livid flames, was not so utterly obscure as over the 

 vault of the heavens. . . . Having used the net during one 

 night, I allowed it to become partially dry ; and having occa- 

 sion, twelve hours afterward, to employ it again, I found the 

 whole surface sparkling as brightly as when first taken out 

 of the water. It does not appear probable, in this case, that 

 the particles could have remained so long alive. On one 

 occasion, having kept a sea-jelly of the genus Biancea till it 

 was dead, the water in which it was placed became luminous. 

 . . . Near Fernando Do Norhona, the sea gave out light in 

 flashes. The appearance was very similar to that which 

 might be expected from a large fish moving rapidly through 

 a luminous fluid. To this cause the sailors attributed it ; at 

 the time, however, I entertained some doubts, on account 

 of the frequency and rapidity of the flashes." 



To Spallanzani is due the credit of first calling attention to 

 the phosphorescence of the jelly-fishes or sea-jellies; he having 

 observed it in the Mediterranean jelly, Pelagia phosphorea, 

 which is luminous over its entire surface. He subsequently 

 made some interesting experiments with Aurelia phosphorea, 

 a jelly-fish similar to one on our coast, and came to the conclu- 

 sion that the light-emitting organs lay in the arms, tentacles. 



