Latitude, 4 deg. 31' 30" south; longitude, 73 deg. 27' west of Greenwich; magnetic variation, 7 deg. 2' east; thermometer, 78 deg.; elevation above sea-level, 320 feet; distance from the Atlantic, 2195 miles; current 3-1/4 miles per hour; depth of water, 30 feet; width of river, 1200 yards. Situated on the north bank of the Amazon, near the confluence of that river and the Ucayali, Nauta is well located for grasping the trade of both rivers, and ought to become a place of importance. Of course, the six or seven miles that vessels have to ascend the Amazon to reach the place after leaving the Ucayali constitutes a drawback, especially in the case of vessels not propelled by steam; but no desirable place can be found below and near the mouth of the Ucayali where buildings could be erected and vessels could load and unload with facility at the season of high water. Below and adjoining Nauta the banks are high and present a better site for a town than the one on which it stands. SAN REGIS. Distant from the Atlantic 2230 miles; current, 3-1/3 miles per hour; average current between Nauta and San Regis, 3-1/4 miles per hour. MOUTH OF THE TIGREYACU RIVER. Distance from the Atlantic, 2245 miles; current, 3-1/2 miles per hour; average current between San Regis and the mouth of the Tigreyacu, 3-1/4 miles per hour. The Tigreyacu can be navigated by steamers of considerable size for some distance; its waters are dark and clear, and those tributaries of the Amazon having dark and clear waters are usually unhealthy, whilst those having muddy and discolored waters have always been found to be healthy. SANTA CRUZ DE PARINARI. Latitude, 4 deg. 36' 30" south; longitude 74 deg. 6' 30" west of Greenwich; magnetic variation, 7 deg. 27' 20" east; thermometer, 78 deg.; elevation above sea-level, 351 feet; distance from the Atlantic, 2273 miles; current, 3-1/4 miles per hour. PARANARI. Distance from the Atlantic, 2293 miles; current, 3-1/4 miles per hour. VACA MARINA. Distance from the Atlantic, 2334 miles; current, 3-1/4 miles per hour. ELVIRA. Distance from the Atlantic, 2352 miles; current, 3-1/4 miles per hour. SAN PEDRO. Distance from the Atlantic, 2393 miles; current, 3-1/4 miles per hour. FONTEVERA. Distance from the Atlantic, 2408 miles; current, 3-1/4 miles per hour. MOUTH OF THE HUALLAGA RIVER. Distance from the Atlantic, 2430 miles; current in Amazon, 3-1/4 miles per hour. One hundred and twenty-three miles up the Huallaga is the town of Yurimaguas, a centre of trade, to which steamers from Para frequently ascend. CEDRO ISLA. Distant from the Atlantic 2445 miles; current, 3-1/4 miles per hour. MOUTH OF THE PASTAGA RIVER.