ILLUSTRATIONS (36). THE MIRAGE. 137 



(3.3) p. 14. "Towns on the banks of the Steppe-rivers." 



Families who live by raising cattle and do not take part in 

 agricultural pursuits have congregated together in the middle 

 of the Steppe, in small iowns, which, in the cultivated parts 

 of Europe, would scarcely be regarded as villages. Among 

 these are Calabozo, which, according to my astronomical 

 observations, is situated in 8 56' 14" north lat., and 67 43' 

 west long. ; Villa del Pao (8 38' 1" north lat., and 66 57' 

 west long.); Saint Sebastian, and others. 



(34) p. 14. " Funnel-shaped clouds." 



The singular phenomenon of these sand-spouts, of which we 

 see something analogous on the cross roads of Europe, is 

 especially characteristic of the Peruvian sandy desert between 

 Amotape and Coquimbo. Such dense clouds of sand may 

 endanger the safety of the traveller who does not cautiously 

 avoid them. It is remarkable that these partial and opposing 

 currents of air should arise only when there is a general calm. 

 The aerial ocean resembles the sea in this respect ; for here, 

 too, we find that the small currents (Jilets de courant) in 

 which the water may frequently be heard to flow with a 

 splashing sound, occur only in a dead calm (cahne plat). 



(35) p. 14. "Increases the stifling oppression" 



I have observed in the Llanos de Apure, at the cattle 

 farm of Guadalupe, that the thermometer rose from 92. 7 to 

 9 7. 2 Fahr. whenever the hot wind began to blow from the 

 desert, which was covered either with sand or short withered 

 grass. In the middle of the sand-cloud the thermometer 

 stood for several minutes together at 111 Fahr. The dry 

 sand in the village of San Fernando de Apure had a tempera- 

 ture of 1 26 Fahr. 



(36) p. 15. " The phantom of a moving undulating surface" 



The well known phenomenon of the mirage is called in 



Sanscrit " the thirst of the gazelle."* All objects appear to 



float in the air, while their forms are reflected in the lower 



stratum of the atmosphere. At such times the whole desert 



See my Relat, hist., t. i. pp. 296, 625; t. ii. p. 161. 



