ihe Luminosity of the Sea. 607 



but the decomposition of animal or vegetable matter, in various 

 stages, is a much more plausible reason. Mr. Baird merely 

 states, to the contrary, that, when fishes and other marine ani- 

 mals have fairly commenced the putrefactive process, their 

 luminosity ceases altogether : thus, in fact, admitting that in 

 certain stages of their decomposition they are luminous. But is 

 not this supposition greatly strengthened by the circumstance 

 above alluded to, that the light is excited by friction or motion? 

 Mr. Sharpe expressly states that it was not until the water in 

 the bucket was shaken that the luminosity appeared ; Mr. 

 Woodward states (p. 285.) that the edges or divisions of the 

 waves became lun^nous, and the spray from the oars particularly 

 so, and that every disturbance of the water gave out a brilHant 

 flash of phosphoric light (Viviani describes his animalcules 

 in a work with the title Phosphor escenti a Maris) ; Mr. Baird, 

 more elegantly, tells us that the light appears when the bow 

 of the vessel throws the water to each side, as it gracefully 

 parts the yielding waves ; and Mr. Thompson's first variety 

 of luminosity sparkles in the spray of the ship, and in the foam 

 created by her way, when the water is agitated by winds or 

 currents ; sometimes even, in stormy weather, enveloping the 

 sails in a sparkling shower as the foam is dashed over the ship. 

 Now, in all these instances, it appears evident that it is only 

 upon the contact of the matter with which the surface of the 

 ocean is at such times impregnated with the atmospheric air 

 that the light is given out, since, if the animals were per se 

 luminous, the light would constantly appear, and not merely 

 when the water is disturbed ; or at least it is not to be sup- 

 posed (even if it be admitted that the animals have the power 

 of emitting light at will) that they never do so except when 

 the water is disturbed, and comes in contact with the atmo- 

 spheric air. As to the nature of the matter or fluid with which 

 the ocean is at these times impregnated, and which I consider 

 to be the primary cause of the phenomenon, it is only by the 

 assistance of chemical analysis that we can arrive at certain 

 conclusions. 



But we are told that every marine animal is luminous, and 

 it is acknowledged by most authors, that animalcules have 

 been caught in the very act of giving out the luminous ap- 

 pearance in vast numbers. This, however, I conceive to be 

 rather a corroboration of my idea, that these animals are a 

 secondary but not primary cause ; since, if the water be at 

 certain times charged with some matter or liquid, which 

 when agitated has the power of emitting light, it would neces- 

 sarily follow^ that if any living animalcules were to find their 

 way into such impregnated water, they must necessarily by 



