BEES SUMMIT OF THE SILLA. 133 



where the horizon was well defined, and the great 

 chain of mountains in the distant south, a dense fog 

 arose from the plains, and they were obliged to use 

 all expedition in completing their observations. 



When seated on the rock, employed in determin- 

 ing the dip of the needle, Humboldt found his hands 

 covered by a species of hairy bee, a little smaller 

 than the honey-bee of Europe. These insects make 

 their nest in the ground, seldom fly, move very 

 slowly, and are apt to use their sting, the guides 

 asserting that they do so only when seized by the 

 legs. 



The temperature varied from 52 to 57, accord- 

 ing as the weather was calm or otherwise. . The 

 dip of the needle was one centesimal degree less 

 than at Caraccas. The breeze was from the east, 

 which might indicate that the trade-winds extend 

 in this latitude much higher than 9600 feet. The 

 blue of the atmosphere was deeper than on the coasts, 

 Saussure'scyanometer indicating 26'5, while at Ca- 

 raccas it generally gave only 18 in fine dry weather. 

 The phenomenon that most struck the travellers was 

 the apparent aridity of the air, which seemed to in- 

 crease as the mist thickened, the hygrometer retro- 

 grading, and their clothes remaining dry. 



As it would have been imprudent to remain long 

 in a dense fog on the brink of a precipice, the trav- 

 ellers descended the eastern dome, and on regaining 

 the hollow between the two summits, were sur- 

 prised to find round pebbles of quartz, a phenomenon 

 which perhaps indicates that the mountain has been 

 raised by a power applied from below. Relinquish- 

 ing their design of passing the night in that valley, 

 and having again found the path which they had cut 

 through the wood, they soon arrived at the district 

 of resinous shrubs, where they lingered so long col- 

 lecting plants that darkness surprised them as they 

 entered the savanna. The moon was up, but every 

 M 



