90 M. Boussingault's Account of 



the glaciers may be compared to condensers which project up- 

 wards into higher regions of the atmosphere, in order by cool- 

 ing to dry the atmosphere, and restore to the surface of the 

 earth the water which the atmosphere contained in the form of 

 vapour. 



The plateaus, surrounded by glaciers, present a melancholy 

 appearance, when a continued wind carries thither moist air 

 from warm regions. The mountains are obscured from view ; 

 and a bank of clouds, which seems to touch the earth, covers 

 the horizon. The day is cold and moist, for this mass of va- 

 pour is almost impenetrable to the rays of the sun. A long 

 twilight takes place, the only one known under the tropics ; for 

 in the equatorial zone the night follows the day so suddenly, 

 that one would be inclined to believe that the sun was extin- 

 guished at its setting. 



I could not better terminate my investigations on the tra- 

 chyte of the Cordilleras than by a particular examination of 

 Chimborazo. To pursue this object, it was only necessary, it 

 is true, to approach the foot of the mountain ; but the hope of 

 obtaining the mean temperature of a very high station induced 

 me to attempt the ascent, and, though my hope was not ful- 

 filled, yet I trust the expedition will not be without its use for 

 science. I mention here the causes which led me to ascend 

 Chimborazo, because I must severely blame the perilous at- 

 tempt when it is not undertaken in the cause of science. Thus 

 to me it appears that Saussure is the only one who has reached 

 the summit of Mont Blanc, notwithstanding that since the time 

 of that distinguished traveller the mountain has been more than 

 once ascended. To his imitators we have no thanks to render, 

 for they have taught us nothing worth the risk of such a jour- 

 ney. 



My friend Colonel Hall, who had already accompanied me 

 to Antisana and Cotapaxi, wished to join me on my present 

 journey, in order to complete the extensive information he pos- 

 sessed regarding the Province of Quito, and to prosecute his 

 investigations on the geography of plants. 



From Rio-Bamba are seen two extremities of Chimborazo of 

 very different inclinations. One, towards Arenal, is very steep, 

 and presents pinnacles of trachyte projecting from the ice. The 



