idth of river, 1200 yards.

MOUTH OF THE PACHITEA RIVER.

Latitude, 8 deg. 43' 30" south; longitude, 74 deg. 32' 30" west of
Greenwich; magnetic variation, 8 deg. 45' 40" east; thermometer, 75
deg.; 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 deg. 41' south; longitude, 73 deg. 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 2189
(Amazon River.)
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 r