On the Luminous Appearance of the Sea. J0\ 



them, Fahrenheit's thermometer flood at 54°. The water 

 itfelf, when at reft, was quite dark; but, when a ftick was 

 drawn through it, the whole part through which the ftick 

 had parTed became luminous, and no light appeared any 

 where elfe. When he agitated the whole water, it became 

 luminous throughout. When the fifh had lain in the water 

 forty-eight hours, it was then brighteft : at the end of three 

 days, though ever fo much agitated, it emitted no more 

 light. 



The fea water, however, exhibited a much more luminous 

 appearance when a herring was placed in it. The third 

 night it was fo ftrong, that, when ftirred, a perfon could tell 

 by it the hour on a watch; and at thofe moments the fifh 

 feemed to be an opake body. After this period the light 

 decreafed more and more, but it ftill continued, in fonte 

 degree, till the feventh night. 



Another veffel containing frefh water, into which a freflt 

 herring was put in the like manner, continued entirely dark, 

 without emitting the leaft trace of light. The thermometer 

 during the time ftood always above 6o°. 



River water, in which fait was diffblved till it appeared by 

 9. hydrometer that it had acquired the gravity of fea water, 

 exhibited the fame phaenomena as water brought from the 

 fea: in water to which more fait was added, the fifh emitted 

 no light. 



It appears from thefe experiments and thofe of Sir John 

 Pringle* that the fait in fea water promotes putrefaction ; 

 and that therefore the luminous appearance of fea water arifes 1 

 from a difpofition to putrefaction, or a commencement of it. 



Experiments on the fliining of fifh in fait water have been 

 made alfo by other philofophers befides Canton : among thefe 

 we may mention thofe of Boyle and Dr. Beal in the Philo- 

 fophical Tra n factions f, and thofe of Martin in the Tranfac- 

 tions of the Swedifh Academy!, all of which feem to con- 

 firm, in a greater or lefs degree, that the luminous appear- 



* Experiments on Septic and Antifeptic Subftances. 



+ Philofophical Tranfactions, No. 31, p. 581 ; and No. 13, p. *i6. 



£ Swedilk Tranfactions, Vol. XIII. p. 2*5. 



an eft 



