rUOSVHORESCENCE OF A NIMA LCiJLJE. 6 1 



coloured band in the Soutliern Atlantic Ocean. 

 Again, in the Paciiic Ocean, going from Valparaiso 

 to Callao, the port of Lima, the sea assumed a deep 

 olive-green colour, owing to a thin mud or slime 

 which it held in suspension : — 



*• Latitude 13° 50' S. ; longitude 76° 51' W.— During 

 the watch, we had remarked an extraordinary colour 

 in the water of the sea ; the tint had changed to a 

 deep olive-green. On the 22nd of May, the plum- 

 met found bottom at less than 700 feet, and made us 

 aware of the fact that the mud was of the same 

 colour, but of a clearer tint. The commander, M. 

 Dupetit-Thouars, by means of dredging, brought up 

 a considerable quantity of the same mud, of which 

 some samples were retained. The substance is al- 

 most impalpable, and has no odour in its natural 

 state ; but when calcined, it diffuses a strong odour, 

 like that of burnt animal matter, and leaves a con- 

 siderable quantity of a whitish-grey ash. Even the 

 surface-water contained this matter in suspension, for 

 the ship's hull at the water-mark was covered with 

 a thin layer of it. It was evidently to this matter 

 that the sea was indebted for its deep olive-green 

 colouring, the j)ermanence of which in these lati- 

 tudes, notwithstanding the strength of the current^ 

 which carries the waters northward, is a curious fact. 

 Aie we to suppose that the tropical heat penetrating 



