IRr.n.] PHOSPHORESCENCE OF THE SEA. 163 



As we proceed further southward the sea is seldom phospho- 

 rescent ; and off Cape Horn I do not recollect more than once 

 having seen it so, and then it was far from being brilliant. This 

 circumstance probably has a close connexion with the scarcity of 

 organic beings in that part of the ocean. After the elaborate 

 paper * by Ehrenberg, on the phosphorescence of the sea, it is 

 almost superfluous on my part to make any observations on the 

 subject. I may however add, that the same torn and irregular 

 particles of gelatinous matter, described by Ehrenberg, seem in 

 the southern as well as in the northern hemisphere, to be the 

 common cause of this phenomenon. The particles were so 

 minute as easily to pass tlirough fine gauze ; yet many were dis- 

 tinctly visible by the naked eye. The water when placed in a 

 tumbler and agitated, gave out sparks, but a small portion in a 

 watch -glass scarcely ever was luminous. Ehrenberg states that 

 these particles all retain a certain degree of irritability. My 

 observations, some of which were made directly after taking up 

 the water, gave a different result. I may also mention, that 

 having used the net during one night, I allowed it to become 

 partially dry, and having occasion twelve hours afterwards to 

 employ it again, I found the whole surface sparkled as brightly 

 as when first taken out of the water. It does not appear pro- 

 bable in this case, that the particles could have remained so long 

 alive. On one occasion having kept a jelly-fish of the genus 

 Dianaea till it was dead, the water in which it was placed became 

 luminous. When the waves scintillate with bright green sparks, 

 I believe it is generally owing to minute Crustacea. But there 

 can be no doubt that very many other pelagic animals, when 

 alive, are phosphorescent. 



On two occasions I have observed the sea luminous at con- 

 siderable depths beneath the surface. Near the mouth of the 

 Plata some circular and oval patches, from two to four yards in 

 diameter, and with defined outlines, shone with a steady but pale 

 light ; while the surrounding water only gave out a few sparks. 

 The appearance resembled the reflection of the moon, or some 

 luminous body ; for the edges were sinuous from the undulations 

 of the surface. The ship, which drew thirteen feet water, passed 



* An abst'.act is given in No IV. of the Magazine of Zoology and 

 Ifotany. 



