AERIAL SPECTKES BY REFLEXION. 145 



its movements. This distinguished traveller ob- 

 served similar phenomena in the barren steppes 

 of the Caraccas, and on the borders of the 

 Orinoco, where the river is surrounded by sandy 

 plains. Little hills and chains of hills appeared 

 suspended in the air, when seen from the steppes, 

 at three or four leagues' distance. Palm-trees 

 standing single in the Llanos appeared to be cut 

 off at bottom, as if a stratum of air separated 

 them from the ground; and, as in the African 

 desert, plains destitute of vegetation appeared to 

 be rivers or lakes. At the Mesa de Pavona M. 

 Humboldt and M. Bonpland saw cows suspended 

 in the air at the distance of 1000 toises, and hav- 

 ing their feet elevated 3' 20" above the soil. In 

 this case the images were erect, but the travellers 

 learned from good authority that inverted images 

 of horses had been seen suspended in the air near 

 Calabozo. 



In all these cases of aerial spectres, the images 

 were directly above the real object; but a curious 

 case was observed by Messrs. Jurine and Soret 

 on the 17th September, 1818, where the image 

 of the vessel was on one side of the real one. 

 About 10 P.M. a barque at the distance of about 

 4000 toises from Bellerive, on the lake of Geneva, 

 was seen approaching to Geneva by the left bank 

 of the lake, and _at the same time an image of 

 the sails was observed above the water, which, 

 insead of following the direction of the barque, 

 separated from it, and appeared to approach 

 Geneva by the right bank of the lake, the image 

 moving from east to west, while the barque moved 

 from north to south. When the image first sepa- 

 rated from the barque they had both the same 



