Latitude, 8° 43' 30" south; longitude, 74° 32' 30" west of Greenwich; magnetic variation, 8° 45' 40" east; thermometer, 75°; elevation above sea-level, 508 feet; distance from the Atlantic, 2891 miles; current, 3 miles per hour; width of the river, 600 yards.
VUELTA DEL DIABLO.
Distance from the Atlantic, 3091 miles. This strait is the first serious difficulty encountered in ascending the Ucayali; the current dashes with much violence against the trunks of large trees which lodge in, and almost block up, the passage.
CONFLUENCE OF THE TAMBO AND URABAMBA RIVERS.
Latitude, 10° 41' south; longitude, 73° 41' west of Greenwich; elevation above sea-level, 661 feet; distance from the Atlantic, 3142 miles; depth of water, 12 feet.
ESPERANZA.
Esperanza is situated on the Perene river about 11 miles above the junction of the Ene and Perene, which form the Tambo. The navigation for steamers drawing 10 feet of water terminates at the junction of the Perene and Ene. From thence to Fort San Ramon, a distance of sixty miles, canoes could navigate, but with some difficulty, owing to the swiftness of the current, which at San Ramon runs at the rate of 6 miles per hour. Small stern-wheel, flat-bottomed steamers, such as are in use on the swift, narrow and shallow rivers west of the Mississippi, could probably be employed with success in establishing communication between Fort San Ramon and the Ucayali.
LIST OF DISTANCES ON THE UCAYALI RIVER.
| Ucayali River. Miles. | |
| Atlantic ocean to mouth of the Ucayali (Amazon River.) | 2189 |
| Mouth of the Ucayali to Pucacura | 293 |
| Pucacura to Sarayacu | 96 |
| Sarayacu to Pacamashi | 155 |
| Pacamashi to Yarinacocha | 67 |
| Yarinacocha to mouth of the Pachitea river | 91 |
| Mouth of the Pachitea to Vuelta del Diablo | 200 |
| Vuelta del Diablo to confluence of the Tambo and Urubamba | 51 |
| Confluence of the Tambo and Urubamba to the Ucayali, source of the Urubamba river, a continuation of the Ucayali | 375 |
| Ucayali river, from its source to the Atlantic | 3517 |
| Distance from the Atlantic to the head of steamer navigation on the Ucayali | 3142 |