Experiinents on the Noctiluca miliaris. 405 



which immediately under the eye resembles milk, or looks as 

 though the keel stirred up a sediment of chalk which diffuses 

 itself in opake clouds through the neighbouring water, only 

 that it is light and not whiteness. Scattered about this cloudi- 

 ness, and particularly where the water whirls and eddies with 

 the motion of the rudder, are seen innumerable sparks of light 

 distinctly traced above the mass by their brilliancy, some of 

 which vanish and others appear, while others seem to remain 

 visible for some time. Generally speaking, both these phae- 

 nomena are excited by the action of the vessel through the 

 waves, though a few sparks may be observed on the surface 

 of the waves around. But now and then, when a short sea is 

 running without breaking waves, there are seen broad flashes 

 of light from the surface of a wave, coming and going like sud- 

 den fitful flashes of lightning. These may be traced as far as the 

 eye can reach, and in their intermittent gleams are very beauti- 

 ful ; they have no connexion with the motion of the ship*." 



When we inquire more precisely into the particular sources 

 of this marine light, we find it distributed, as before mentioned, 

 far more extensively amongst the various grades of animal life 

 in the ocean, than amongst those of the land. Although the 

 fact has been somewhat called in question, and the light attri- 

 buted to the disturbance of the surrounding luminous water, 

 yet there appears little doubt that the power of phosphores- 

 cence is actually possessed by animals ranking as high as the 

 class of fishes. Thus in the narrative of Mr. F. D. Bennett, 

 above alluded to, after referring the general luminosity of the 

 ocean on a particular occasion to the presence oi Medusae, he 

 proceeds : *' Though the discovery of these Medusae was a 

 satisfactory explanation of the phosphorescent appearance of 

 the water, 1 liad yet to learn that the latter effect was partly 

 produced by living, bony, and perfectly organized fish : such 

 fish were numerous in the sea this night; and a tow-net cap- 

 tured ten of them in the space of a few hours. They were a 

 species oi Scopehis, three inches in length, covered with scales 

 of a steel-gray colour, and the fins spotted with gray. Each 

 side of the margin of the abdomen was occupied by a single 

 row of small and circular depressions of the same metallic- 

 gray hue as the scales ; a few similar depressions being scat- 

 tered also on the sides, but with less regularity. The exam- 

 ples we obtained were alive when taken from the net, and 

 swam about actively upon being placed in a vessel of sea- 

 water. When handled or swimming, they emitted a vivid 

 phosphorescent light from the scales, or plates, covering the 

 body and head, as well as from the circular depressions on the 



* Page 365. 



