56 Dr Gillies's Observations on 



the mountains, by this road, for the supply of Chile and Peru. 

 At I>a Tunta de las Vacas, the Incas road again leaves the 

 high road, and may be traced across the river of Mendoza, and 

 along the Valley of Topongato, to the foot of the lofty moun- 

 tain of that name, by which, it passes into the Valley of the 

 Tenuyan. 



The early Spanish writers on these countries give details re- 

 specting these royal roads of the Incas ; and, among other 

 things, state, that from Cusco there existed a double line of 

 these roads, over an extent of about 500 leagues, towards Quito, 

 the one being made along the plains, at great trouble and ex- 

 pence, to obviate the difficulties presented by a sandy and loose 

 soil, and the other along the mountains, in which cases ridges 

 •were levelled and valleys filled up, the latter being preferred in 

 summer. These roads were twenty-five feet wide, and, at regu- 

 lar distances, had palaces, store-houses, and other habitations, 

 for the use of the officers of the royal house and of the revenue. 

 From Cusco these roads also proceeded in a southerly direction, 

 dividing into several branches, one of which passing through 

 Potosl, was continued by the route now called Camino del Des- 

 poblado, along the Cordillera of the Andes, belonging to Salta, 

 La Rioja, San Juan, and Mendoza, the continuation of which 

 is seen at Uspallata. This branch must have been originally 

 formed for the purpose of communicating with the Araucanian 

 Indians, and the other nations inhabiting Chile, and those tribes 

 which inhabit the country along the eastern side of the Southern 

 Cordillera of the Andes, and from thence to the Southern At- 

 lantic Ocean and Cape Horn, all of whom are of quite a diffe- 

 rent race, and speak a language very different from the Quichoa, 

 or language of the Peruvian Indians. The cause why they 

 seem to have preferred this route to any other, may be suppos- 

 ed to have been the greater abundance of water and other con- 

 veniences for travellers, than along either side of the mountains ; 

 these, in many places, being very scarce on the eastern side, and 

 are altogether avsanting on the western, where the desert of 

 Atacama, bounded on the one side by the Pacific Ocean, and on 

 the other by the Andes, is quite impassable. Be^sides, the moun- 

 tain route may be presumed to have been safer, more free from 

 jinterruptlon, and more centrical for the purpose of communica- 



