POETION OF THE COSMOS. VISUAL POWER. 55 



eastern Alps to the summit of the Grosglockner (12213 

 Fr., or 13016 Eng. feet*), were never able to see stars in 

 the day-time, nor did they hear any statement to that effect 

 among the herdsmen and chamois hunters. T spent several 

 years in the Cordilleras of Mexico, Quito, and Peru, and 

 was very often, together with my friend Bonpland, in clear 

 weather on heights of upwards of fifteen or sixteen thousand 

 (English) feet ; and neither we, nor subsequently Boussin- 

 gault, could ever recognise stars in the day-time, although 

 the azure of the sky was so deep and dark, that with the same 

 cyanometer of Paul of Geneva with which Saussure had 

 read 39 on Mont Blanc, I should have found under the 

 tropics, at elevations between 16000 and 18000 (17052 

 and 19184 Eng.) feet, 46 at the zenith. ( 112 ) Under the 

 magnificent, ethereally pure and serene sky of Cumana, on 

 the plain of the sea-shore, after the observation of occulta- 

 tions of Jupiter's satellites, I have several times with ease 

 found the planet again with the naked eye,, and seen him 

 most distinctly whilst the sun's disk was 18 or 20 above 

 the horizon. 



This is the proper place in which to notice, at least in a 

 cursory manner, another optical phsenomenon which, among 

 my many ascents of mountains, was only observed by me 

 once viz. on the 22nd of June, 1799, before sunrise, on 

 the declivity of the Peak of Teneriffe. Being in the Mai- 

 pays, 10700 (11404 Eng.) feet above the sea, I saw with 

 the naked eye stars low down near the horizon in strange 



[* Since given more correctly by Messrs. H. and A. Schlagintweit 

 12158 French or 12958 English feet, in their Physicalische Geographic der 

 Alpen. ED.] 



