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III. Luminous Appearance, of Ocean-Water caufed by Anl* 

 mals: in a Letter from Prof e //or M itch ill, of New - 

 \ irk, to Profe/Jbr Bart on, of Philadelphia*. 



OO obvious an appearance as the phofphorefcence of ocean- 

 water was afcribed to animals as long ago as the time of Pliny. 

 Some of thefe adhering to the rigging of veifels in windy and 

 flormy w\ her, and finning in the dark, feem to have caufed 

 the appeal ances known formerly by the names of Caftor and 

 Pollux. Much has been offered on this fubjeft, both phy- 

 fically and hiftoricallv, you know, by Charles Frederic Adler, 

 in his DifJ'ertatio de Nocliluca JMarina, which is well worthy 

 of perufal. He has given a magnified figure of a microfcopic 

 worm, which, in the fea of China, makes the fait water lu- 

 minous. It is called by fome French writers fcolopendre 

 marine luifante, and bv Linne nereis noftiluca. Some of the 

 lea-jellies and fea-blubbers have alfo been long known to be 

 occafionally luminous. The principal part of thefe are me- 

 dufas, which, at a very early *. day, obtruded themfelves on 

 the attention of naturalifts. But, notwithstanding all this, 

 the philofophical world feems ftill to be a good deal undecided 

 as to the real caufe of the phofphorefcence of the ocean. I 

 have therefore recorded the following facls, which fell under 

 my own eye, hoping they may not be without their ufe in 

 explaining the phenomenon. Pennant, in his Britifh Zoo- 

 logv, vol. iv. exprefles very juft ideas on the fubjeel:. 



On the evening of Saturday, the 13th of September 1800, 

 about high water, as we were preparing, between feven and 

 eight o'clock ^ to bathe in the bay, my attention was called 

 to a remarkable luminous appearance at the water's edge on 

 the beach. The wind was from the fouthward, and the day 

 had been fo warm, that about two P. M. the quickfilver in a 

 thermometer hanging in a {haded piazza, on the fouth fide 

 of the houfe, had rifen to 89 degrees. At this moment it 

 flood as high as 76. The diftance from the chamber win- 

 dows to high water mark is 210 feet. It feemed as if the 

 beach was covered with coals of fire, and that bright fparkles 

 were conftantly emitted among them; The fmall undula- 

 tion which moved to land looked like a wave of flame rolling 

 along the fhore ; and the water beyond, to the diftance of a 

 few rods, exhibited frequent corrufcations of extraordinary 

 brightnefs. On going down" to the water, I found the fand 

 covered with molfufca animals, the greater part of which 

 were the medufa Jimplex. Thoufands of them had juft been 



* Communicated to the Editor by the Author. 



left 



