ON THE LUMINOSITY OF THE SEA. 469 



ney, (Philosoph. Trans, p. 260, for 1810.) The 

 animal when at rest, exhibited a somewhat crescent 

 form. The ciliary processes of the ribs, which in 

 swimming described a kind of tortuous motion, 

 seemed to be those parts from whence the light was 

 derived, but of which the whole body occasionally 

 partook. The Beroe died a few minutes after I 

 had received it, which I attributed to the light of 

 the candle, rather than to increment of tempera- 

 ture in the medium. When taken up on the point 

 of a probe, it had the appearance, and nearly the 

 consistency, of jelly; it was diaphanous, and present- 

 ed a spherical figure of about one-sixth of an inch 

 in diameter. 



The late Professor Smith of Christiana considers 

 that the luminous appearance which diffuses itself 

 over the whole surface of the sea in the Atlantic, 

 arises from a dissolved! slimy matter ; and that the 

 most minute glittering particles, when highly mag- 

 nified, had the appearance of solid spherical bodies. 

 I cannot doubt, but that these luminous particles 

 originated with some of the mollusca and Crustacea 

 adverted to ; and that they had been detached by the 

 action of the waves, or friction, the consequence of 

 other causes, as may appear in the sequel. 



Another quantity of sea-water presented me the 

 Medusa, perhaps the species called scintillans. I 

 could discover no other kinds. The medusa was 

 about three- fourths of an inch diameter. It died 

 very shortly after I brought it home ; and perhaps 



