ANNOTATIONS AND ADDITIONS. -13 



extension) lias a great influence on the minimum of thi? 

 angle. The transparency of the mountain atmosphere at 

 the equator is such that, in the province of Quito, as I have 

 elsewhere noticed, the white mantle or Poncho of a horse- 

 man was distinguished with the naked eye at a horizontal 

 distance of 84132 (89 6 6 5' English) feet; therefore under a 

 visual angle of 13 seconds. It was my friend Bonpland, 

 whom, from the pleasant country seat of the Marques de 

 Selvalegre, we saw moving along the face of a black precipice 

 on the Yolcano of Pichincha. Lightning conductors, being 

 long thin objects, are seen, as has already been remarked by 

 Arago, from the greatest distances, and under the smallest 

 angles. 



The accounts of the habits of the Condor in the moun- 

 tainous districts of Quito and Peru, given by me in a 

 monograph on this powerful bird, have been confirmed by a 

 later traveller, Gay, who has explored the whole of Chili, and 

 has described that country in an excellent work entitled 

 Historia fisica y politica de Chile. The Condor, which, 

 like the Lamas, Vicunas, Alpacas, and Guanacos, does not 

 extend beyond the equator into New Granada, is found as 

 far south as the Straits of Magellan. In Chili, as in the 

 mountain plains of Quito, the Condors, which at other 

 times live either solitarily or in pairs, assemble in flocks to 

 gttack lambs and calves, or to carry off young Guanacos 

 (Guanacillos). The ravages annually committed among the 

 herds of sheep, goats, and cattle, as well as among the wild 

 Vicunas, Alpacas, and Guanacos of the Andes, are very 

 considerable. The inhabitants of Chili assert that, in cap- 



