172 
ATLANTIC OCEAN 
CHAP. 
time. The central and intertropical parts of the Atlantic 
swarm with Pteropoda, Crustacea, and Radiata, and with their 
devourers the flying-fish, and again with their devourers the 
bonitos and albicores ; I presume that the numerous lower 
pelagic animals feed on the Infusoria, which are now known, 
from the researches of Ehrenberg, to abound in the open ocean : 
but on what, in the clear blue water, do these Infusoria 
subsist ? 
While sailing a little south of the Plata on one very dark 
night, the sea presented a wonderful and most beautiful spec¬ 
tacle. There was a fresh breeze, and every part of the surface, 
which during the day is seen as foam, now glowed with a pale 
light. The vessel drove before her bows two billows of liquid 
phosphorus, 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. 
As we proceed farther southward the sea is seldom phos¬ 
phorescent ; 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 connection with the 
scarcity of organic beings in that part of the ocean. After the 
elaborate paper 1 by Ehrenberg, on the phosphorescence of the 
sea, it is almost superfluous on my part to make any observa¬ 
tions 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 through fine 
gauze ; yet many were distinctly 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 
1 An abstract is given in No. IV. of the Magazine of Zoology and Botany. 
