PAIRING OF INSECTS. 233 



surface was broken by the ripple of the tide, or when 

 a wave dashed upon the pebbles on the beach.* 



Humboldt, however, is of opinion, that though 

 the phenomenon is only at times caused by animated 

 lamp-bearers, it may probably arise in general from 

 the decomposed fibrillge of dead mollusca which 

 abound beyond all calculation in the bosom of the 

 waters. He proved this by passing some of the 

 luminous water through cloth, when some of the 

 fibrillae were separated, and appeared in the form of 

 luminous points. We should, on the other hand, 

 have been inclined to infer that these points were 

 caused by the luminous water moistening the fibres 

 of the cloth : and our author himself afterwards seems 

 to abandon the notion of fibrillar for that of a gela- 

 tinous fluid produced by the decomposition of the 

 dead bodies, and imparting to sea-water the nauseous 

 taste, which is as much disliked by us as it is relished 

 by the fishes. Water may thus be rendered luminous 

 by throwing into it a quantity of herring brine, and 

 hence it appears that salt is indispensable; for, as M. 

 Bory de St Vincent justly remarks, the waters of our 

 lakes and marshes are never luminous, though these 

 abound with polypi, both living and dead. There 

 seem also to be certain states of the air favourable or 

 unfavourable to the development of the light ; for 

 one night it will appear with great brilliance, while 

 on the following, though the circumstances seem all 

 equal, it will be gone. It seems to be more frequent, 

 as Humboldt remarked, ' when the sky was thick 

 and cloudy, and upon the approach of a storm.' 

 We have remarked it as frequently following as 

 precedmg a storm ; but it seems to be independent of 

 heat or cold ; for on the banks of Newfoundland it 

 is observed to shine with great brilUance during the 

 most rigorous frosts. 



* J. R. 



FOL. XII. 20* 



