168 Scientific Intelligence. 



acquainted, has never hitherto been remarked. During a gentle breeze, 

 the continuation of the north-east Trades, the sea appeared uncommonly 

 luminous, and increased gradually in brightness, from a little after sunset 

 until near midnight. The intensity was particularly great about nine 

 o'clock ; and every one who then kept his eyes fixed upon it but for a 

 short time, was immediately seized with headach, giddiness, pain in the 

 eyeballs, and slight sickness. Some on board certainly felt these symp- 

 toms more violently than others; but there was none who was not more 

 or less affected by them. For my own part, the headach, &c. which im- 

 mediately followed my looking at the water, was particularly severe ; nor 

 did it go off until morning. I cannot give a better idea of my sensations, 

 than that the effects resembled those produced from having smoked an 

 over quantity of tobacco. The brightness gradually decreased long before 

 dawn, nor did it ever afterwards impress us with the same peculiar effects 

 I have just described. 



The luminous appearance of the sea seems as yet to have excited but 

 little attention among philosophers, who are content with ascribing it to 

 fish spawn, or animalcules. Of the two, I should rather be inclined to 

 adopt the latter opinion, though their actual existence has not yet been 

 ascertained. The following are my reasons for doing so. 



l.y^. The luminous appearance is greatest where there are evidently few- 

 est fishes. 



2d, They are often seen in great masses, many fathoms from the sur- 

 face. Now, as they do not give light without motion or agitations, it fol- 

 lows that these cannot be in the state of rest their position would lead us 

 to suppose. 



3d, They are of greater size, and more thinly spread in higher latitudes; 

 whereas near the line they become more and more minute, and are seen 

 in infinitely greater numbers. 



4>th, The luminous appearance varies according to the quarter from 

 which the wind blows ; and as fish spawn is, comparatively speaking, in- 

 animate, it is improbable that so slight a cause should produce such a 

 change upon it. 



The shoals of them we observe below the surface appear to be owing to 

 their attaching themselves to animal or vegetable matter, whose specific 

 gravity being somewhat greater than water, it has sunk till it found an 

 equilibrium. I have often observed them with a tolerably good micro- 

 scope ; but the motion of the vessel, and other circumstances, give me 

 little confidence in the experiments I have made. The most interesting 

 subject, however, is the principle in which their resplendent property re- 

 sides. It is generally denominated phosphorescent ; but phosphorus, in 

 its most concentrated state, affords no effect such as I have described. I 

 have witnessed it burning in oxygen gas, while its light almost rivalled 

 that of noon day : its action then upon the eye was nothing more than 

 would have been produced by looking for a few moments at the sun ; 

 while during the phenomenon I have described the slightest beam of that 

 luminary would have rendered the whole invisible. If, therefore, we 



