Cordillera of the Andes, or simply Cordillera, which others improperly call the Cordiliere or the Cordilieres , is the name given to a high chain of Peruvian mountains [1], of which Monsieur Bouguer has given a detailed description in the first part of his work on the shape of the earth. [2] Here is a greatly abridged extract of that description.

M. Bouguer, after having described the part of Peru included between the sea and the Cordillera , first observes that almost all the rivers that flow from the Cordillera into the South Sea [3] are raging torrents. The author, after having walked and climbed with a great deal of effort during several days, and crossed, not without danger, some of these torrents, arrived at the foot of a high mountain called Chimborazo , which is one of those of the Cordillera . See The Lure of Mountains. At the foot of this mountain one finds oneself already above the clouds, in a region where it never rains. [4] Arriving at the top, he wanted to descend, and was quite astonished to find on the other side a pleasant land, agreeable, and temperate, very different from that which he had left. [5] The Cordillera really consists, for the most part, of two parallel mountain chains, between which is a valley which could itself be considered a mountain, being very high above sea level. Quito is located in this valley, and the greater part of its province; the elevation of the sun, combined with the nearness of mountains covered with snow, and the equal length of the days and nights during the entire year, makes the climate here temperate, and one enjoys an eternal spring. Monsieur de Réaumur’s thermometer remained between fourteen and fifteen degrees. Quito is at the base of a mountain called Pichincha , which one can ascend very high on horseback. The base of most of these mountains is a clay soil which produces grasses, and the summit is nothing but a pile of stones.

The cold is extreme on Pichincha and the other mountains; and they are constantly in the clouds; the sky here changes three or four times in half an hour, and the thermometer sometimes varies by seventeen degrees in a single day. Mercury is stable here at six inches, one line, and at twenty-eight inches, one line at sea level. One sometimes sees its shadow projected on the clouds that surround it, and the head of the shadow is adorned with a kind of splendor formed by several concentric circles, with the colors of the first rainbow, red on the outside. See Rainbow.

The height of the rocky summit of Pichincha which is 2434 fathoms above sea level, is like almost all the lower mountains of the torrid zone, constantly covered with snow. We say constantl y because snow is sometimes found below 900 fathoms. On some mountains the snow-line is lower, on some it is higher; and one cannot climb them because the snow has turned to ice. Nevertheless, snow melts higher up on volcanos. See Volcano. This snow-line is lower, as it must be, farther from the equator, for example, on Mount [Teide in] Tenerife, which only has an elevation of 2,100 fathoms. Monsieur Bouguer observes that there also must be, and is, an upper limit, if mountains exist that are so high that clouds never move beyond a certain distance below their summit[s]; but we don’t know anything about such mountains.

In all the high places of the Cordillera , as soon as one passes from shade to sun, one feels a greater difference in the temperature of the air, like here on our most beautiful days: that is because on these high desert mountains covered with snow, and where the air is thin, heat comes mainly from the direct and immediate action of the sun; in lower parts of the earth there are several other causes. See Heat.

Monsieurs Bouguer and de la Condamine climbed Pichincha above the snow-line, to 2476 fathoms in altitude; the barometer was at 15 inches 9 lines, that is, more than twelve inches lower than at sea level: a barometer had never been transported so high.

The western chain of the Cordillera contains a lot of gold, like the foot of the eastern chain. The mountains around Quito appear to contain few parts of metal, although one sometimes finds flakes of gold. For more detail see the work by Monsieur Bouguer cited; also see the account by Monsieur de la Condamine on the same subject in his historical account . [6]

Notes

1. Prior to 1717, what is now Ecuador was included in the Viceroyalty of Peru. Even in the mid-eighteenth century, territory within modern Ecuador was often thought of as part of Peru.

2. Probably La figure de la terre, déterminée par les observations de messieurs Bouguer & de la Condamine, de l’Académie royale des sçiences, envoyés par ordre du roy au Pérou, pour observer aux environs de l’équateur: avec une relation abregée de ce voyage qui contient la description du pays dans lequel les opérations ont été faites . Paris: C.A. Jombert (1749).

3. The Pacific Ocean.

4. There is a confusion here with the hyper-arid western coast of South America from just north of Talara, in what is now northern Peru, to central Chile. In the area around Chimborazo it rains, approximately two days out of every three, and there are about 200 to 400 millimeters of monthly precipitation.

5. Once again there is a confusion between the climate of the central Andes and that of the northern Andes.

6. Probably Journal du voyage fait par ordre du roi, a l’équateur, servant d’introduction historique à la mesure des trois premiers degrés du méridien . Paris: Imprimerie royale (1751).