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.

I have already remarked that the phenomenon is very much more common in warm than in cold countries; and I have sometimes imagined that a disturbed electrical condition of the atmosphere was most favourable to its production.

Certainly I think the sea is most luminous after a few days of more calm weather than ordinary, during which time it has swarmed with various animals.

Observing that the water charged with gelatinous particles is in an impure state, and that the luminous appearance in all common cases is produced by the agitation of the fluid in contact with the atmosphere, I am inclined to consider that the phosphorescence is the result of the decomposition of the organic particles, by which process (one is tempted almost to call it a kind of respiration) the ocean becomes purified.
DECEMBER 23, 1833.
We arrived at Port Desire, situated in latitude 47 degrees, on the coast of Patagonia.