PHOSPHORESCENCE OF THE SEA. 1 15 



I)ushes covered with noctilucous insects, and left with chap. XL 



regret a country in which every thing had appeared ^ . 



new and marvellous. Passing at high water the bar of tiie Man- 

 t]ie river, they entered the Gulf of Cariaco, the surface ^""^'"^*- 

 of which was gently rippled by the evening breeze. In 

 a short time the coasts were recognised only by the 

 scattered lights of the Indian fishermen. 



As they advanced toward the shoal that surrounds c.^pe Arenas. 

 Cape Arenas, stretching as far as the petroleum springs 

 of Maniquarez, they enjoyed one of those beautiful 

 sights which the phosphorescence of the sea so often 

 displays in tropical climates. When tlie porpoises, 

 which followed the boat in bands of fifteen or sixteen, 

 struck the surface of the Avater witli their tails, they 

 produced a brilliant light resembling flames. Each 

 troop left behind it a luminous track ; and as few sparks 

 were caused by the motion of an oar or the track of the 

 l)oat, Humboldt conjectured that the vivid glow pro- 

 duced by these cetaceous animals was owing not to the 

 stroke of their tails alone, but also to the gelatinous 

 matter which envelops their bodies, and which is 

 detaclied by the waves. 



At midnight they found themselves among some .j.,,^ carace.is 

 rocky islets, rising in the form of bastions, and consti- and ciii- 

 tuting the group of the Caraccas and Chimanas. Many "'^"'"' 

 of these eminences are visible from Cumana, and pre- 

 sent the most singular appearances under the effect of 

 mirage. Their heiglit, wliich is probably not more 

 tiian 960 feet, seemed much greater when enlightened 

 I)y the moon, wliich now shone in a clear sky. Tlie 

 travellers were becalmed in the ncighbourliood of these 

 islands, and at sunrise drifted towards Boracha, the j^pj.pjjj.p^ 

 largest of them. The temperature had sensibly in- teiDperature. 

 creased, in consequence of the rocks giving out by 

 radiation a portion of the heat which they had absorbed 

 during the day. As tlie sun rose, the cliffs projected 

 their lengthened shadows upon tlie ocean, and the 

 flamingoe? began to fish in the creeks. These insular 

 spots were all uninhabited ; but on one of them, which 



