28t) UPPER AMAZON. 



CliAP.xxill. trees which yield the Peruvian bark. The vast extent 

 of ground which they traversed in the course of their 

 expedition afforded them better opportunities than any 

 botanist had ever enjoyed of comparing the different 

 species of Cinchona. 



Peru. Leaving Loxa they entered Peru by Ayavaca and 



Guancabamba, traversing the ridge of the Andes to 

 descend to the River Amazon. In two days tliey had 

 to cross twenty-seven times the Rio de Chayma. They 

 saw the magnificent remains of the causeway of the 

 Incas, whicli traversed the porphyritic summits from 

 Cusco to Assouay, at a heiglit varying from 7670 to 

 11,510 feet. At the village of Chaymaya, on a river of 

 the same name, they took ship and descended to the 

 Amazon. 



Geographical La Condamine, on his return from Quito to Para, 



observations, embarked on this river only below Quebrada de Chu- 

 chunga ; and Humboldt, with the view of completing 

 the map made by the French astronomer, proceeded as 

 far as the cataracts of Rentama. At Tomependa, the 

 principal place of the province of Jaen de Bracamorros, 

 he constructed a map of the Upper Amazon, from his 

 own observations as well as from accounts received from 

 the natives. Bonpland employed himself, as usual, in 

 examining the subjects of the vegetable kingdom, 

 among which he discovered several new species of 

 Cinchona. 



Position of Returning to Peru, our travellers crossed the cordil- 



tJio Dia(,Tietic lera of the Andes the fifth time. In seven degrees of 

 equator. ^ 



south latitude they determined the position of the 



magnetic equator, or tlie line in which the needle has no 



inclination. They also examined the mines of Gual- 



gayoc, where large masses of native silver are found at 



an elevation of 1],013 feet above the sea, and which, 



together with those of Pasco and Huantajayo, are the 



richest in Peru. From Caxamarca, celebrated for its 



hot-springs and the ruins of the palace of Ataliualpa, 



they went down to Truxillo. In this neighbourliood 



arc the remains of the ancient Peruvian citv Mansichc 



