144 NATURE'S PHANTASMAGORIA. 



ing flowers, and delicious sparkling lakes ; others see, in that dim far- 

 off which is never reached, the laughing waves of ocean, with ships 

 resting calmly at anchor, or 



" Veering up and down, they know not why," 



and camels browsing quietly upon its shores ; others, again, see before 

 them the rolling river, its banks studded with groves and palaces ; 

 and all this, while there is not a solitary real object on the horizon 

 whose presence might serve in some degree as a foundation for their 

 visions. It is the very phantasmagoria of nature ; her wildest, most 

 wayward, and most fantastic sport. The reflection of the sky, modi- 

 fied by the inequalities of the soil and the vibratory movements of 

 the air, can alone account for the singular deception. Imagination 

 shows its victim, in the reflected image of the cloudless sky, a sheet 

 of water, which is variously taken for a sea, a lake, or a river ; it 

 invests the slightest objects on the earth's surface with forms, colours, 

 and dimensions, which are easily metamorphosed into houses, ships, 

 men, animals ; and it seems certain that those which in Nubia our 

 fancy converts into camels would, in the Soudan, be transformed into 

 elephants, and at Venice into gondolas. Imagination makes us its 

 dupes, and gives to airy nothings 



" A local habitation and a name." 



It becomes absolutely necessary, therefore, to distinguish these 

 wholly personal illusions born of a heated brain, from those which 

 are really due to a definite physical cause. The latter necessarily 

 suppose the existence of actual objects, below or very little above the 

 horizon. Under such conditions, the most frequent illusion is that 

 which shows the sky or rocks reflected in the expanse of rarified air 

 superincumbent on the earth's surface, and which through this cause 

 alone resembles water. It is then that the ignorant or inexperienced 

 traveller, overwhelmed with fatigue and devoured by thirst, hastens 

 his eager steps to reach more quickly that limpid water, where he 

 hopes to refresh and reinvigorate himself, but which flies before his 



