Tension of the vapor, in mm., middle term, 10.98. Relative humidity (saturation = 100), middle term, 77.29. Inferior wind, prevailing direction N. N. E.; rapidity in meters by second, middle term, 3.81. Rain, mm., total: 711.8. Winter is so mild in this country that, in fact, the year may be divided into two seasons--the hot season, from November till April, and the cool season, from May till October. Whatever may be the geographical situation of his own country the foreigner does not need any previous acclimation; when he comes to live in this Republic he does not feel any disorder in his health, owing to the mildness of the temperature. The most ordinary winds are the N., N. E., E, and S. W. winds. This last one, called _Pampero_, is pure and vivifying and is rightly considered as the purifier of the Plate, and one of the principal causes of the wholesomeness which the country enjoys. Rivers--Rivulets--Ports--Docks--Dry Docks. With only looking over the map of the Republic, one gets an idea of its rich hydrography. Sixteen rivers flow through the territory, all being joined by more than 500 rivulets that increase their size and current. The principal rivers are the Plate and Uruguay, which bathe the coasts of the Republic, and the Rio Negro (the black river), which flows all through the center of the territory. The River plate, at its mouth, between cape Santa Maria and cape San Antonio, is more than 206 kilometers wide; its superficies are calculated to be over 39,846 kilom.; its length 361 kilom.; its breadth, between Colonia and Buenos Ayres, a little more than 51 kilom. The River Uruguay flows from N. to S., its length through the Republic is 530 kilom., its breadth from the Guazu down to the point of Fray Bentos varies from 10 to 15 kilom. After passing Fray Bentos it becomes narrow, owing to the multitude of islands which form deep channels. In its normal state it runs three or four miles an hour. It is navigable up to Paysandu for ships of great tonnage, and up to Salto for coast trading boats. The Rio Negro runs through the territory from N. W. to W., with an extension of 463 kilom. It is navigable for ships of small tonnage for 94 kilom., more or less. The other thirteen rivers are: the Cuareim, the Arapey, the Dayman, the Queguay, the Tacuarembo, the Yi, the Yaguaron, the Tacuari, the Olimar Grande, the San Jose, the San Salvador and the Santa Lucia. These powerful arteries, the waters of which are increased by numberless rivulets that empty into them, flow down to the remotest parts of the Republic and fertilize them. The waters of the River Plate, till a little further up than Santa Lucia are salt; beyond this they always remain fresh. The waters of the Uruguay, Rio Negro and other rivers of the interior have the property of petrifying animal and vegetable substances.