LA GRACIOSA. 29 



equal to half of that supplied by a candle seen at 

 the distance of a foot. The g-erms^ of several of 

 the liliacejE, the embryo of the mallows and other 

 families, the branches of some subterraiiean plants, 

 and vegetables transported into mines in which the 

 air contains hydrogen or a great quantity of azote, 

 become green without light. From these facts one 

 might be induced to think that the existence of car- 

 buret of iron, which gives the green colour to the 

 parenchmay of plants, is not dependent upon the 

 presence of the solar rays only. Turner and many 

 other botanists are of opinion that most of the sea- 

 weeds which we find floating on the ocean, and which 

 in certain parts of the Atlantic present the appear- 

 ance of a vast inundated meadow, grow originally 

 at the bottom of the sea, and are torn off by the 

 waves. If this opinion be correct, the family of 

 marine algae presents great difficulties to those physi- 

 ologists who persist in thinking that, in all cases, 

 the absence of light must produce blanching. 



The captain, haviug mistaken a basaltic rock for 

 a castle, saluted it, and sent one of the officers to 

 inquire if the English were cruising in those parts. 

 Our travellers took advantage of the boat to examine 

 the land, which they had regarded as a prolongation 

 of the coasts of Lancerota, but which turned out to 

 be the small island of La Graciosa. " Nothing," 

 says Humboldt, " can express the emotion a natu- 

 ralist feels when for the first time he lands in a place 

 which is not European. The attention is fixed upon 

 so many objects, that one  can hardly give an ac- 

 count of the impressions which he receives. At 

 every step he imagines that he finds a new produc- 

 tion ; and in the midst of this agitation he often does 

 not recognise those which are most common in our 

 botanical gardens and museums." A fisherman, 

 who, having been frightened by the firing, had fled 

 from them, but whom the sailors overtook, stated 

 that no vessels had been seen for several weeks. 



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