58 PHYSIOGNOMY OF PLANTS. 



magnetic lightnings), which, as the result of an increased 

 tension in the interior of the globe, are announced 

 for hours beforehand by the suddenly altered movements 

 of the magnetic needle, (See my letter to the Editor of 

 the Annalen der Physik und Chemie, Bd. xxxvii. 1836, S. 

 242-244). 



Sometimes one cannot even with high magnifying powers 

 discern any animalcules in the luminous water ; and yet, 

 whenever the wave strikes and breaks in foam against a 

 hard body, a light is seen to flash. In such case the cause 

 of the phenomenon probably consists in the decaying 

 animal fibres, which are disseminated in immense abun- 

 dance throughout the body of water. If this luminous 

 water is filtered through fine and closely woven cloths, 

 these little fibres and membranes are separated in the shape 

 of shining points. When we bathed at Cumana in the waters 

 of the Gulf of Cariaco, and afterwards lingered awhile on 

 the solitary beach in the mild evening air without our clothes, 

 parts of our bodies continued luminous from the shining 

 organic particles which had adhered to the skin, and the 

 light only became extinct at the end of some minutes. 

 Considering the enormous quantity of animal life in all 

 tropical seas, it is, perhaps, not surprising that the sea 

 water should be luminous, even where no visible organic 

 particles can be detached from it. From the almost infinite 

 subdivision of the masses of dead Dagysse and Medusse, the 

 sea may perhaps be looked on as a gelatinous fluid, which 

 as such is luminous, distasteful to, and undrinkable by man, 

 and capable of affording nourishment to many fish. If 



