_Boundaries._--Brazil is bounded N. by Colombia, Venezuela and the Guianas, N.E., E. and S.E. by the Atlantic, S. by Uruguay, Paraguay and Bolivia, and W. by Argentina, Paraguay, Bolivia, Peru, Ecuador and Colombia. Its territory touches that of every South American nation, except Chile, and with each one there has been a boundary dispute at some stage in its political life. The Spanish and Portuguese crowns attempted to define the limits between their American colonies in 1750 and 1777, and the lines adopted still serve in great part to separate Brazil from its neighbours. Lack of information regarding the geographical features of the interior, however, led to some indefinite descriptions, and these have been fruitful sources of dispute ever since. The Portuguese were persistent trespassers in early colonial times, and their land-hunger took them far beyond the limits fixed by Pope Alexander VI. In the boundary disputes which have followed, Brazil seems to have pursued this traditional policy, and generally with success.
Beginning at the mouth of the Arroyo del Chuy, at the southern extremity of a long sandbank separating Lake Mirim from the Atlantic (33°45' S. lat.), the boundary line between Brazil and Uruguay passes up that rivulet and across to the most southerly tributary of Lake Mirim, thence down the western shore of that lake to the Jaguarão and up that river to its most southerly source. The line then crosses to the hill-range called Cuchilla de Sant' Anna, which is followed in a north-west direction to the source of the Cuareim, or Quarahy, this river becoming the boundary down to the Uruguay. This line was fixed by the treaty of 1851, by which the control of Lake Mirim remains with Brazil. Beginning at the mouth of the Quarahy, the boundary line between Brazil and Argentina ascends the Uruguay, crosses to the source of the Santo Antonio, and descends that small stream and the Iguassú to the Paraná, where it terminates. This line was defined by the treaty of 1857, and by the decision of President Cleveland in 1895 with regard to the small section between the Uruguay and Iguassú rivers. The boundary with Paraguay was definitely settled in 1872. It ascends the Paraná to the great falls of Guayrá, or Sete Quedas, and thence westward along the water-parting of the Sierra de Maracayú to the _cerro_ of that name, thence northerly along the Sierra d'Amambay to the source of the Estrella, a small tributary of the Apá, and thence down those two streams to the Paraguay. From this point the line ascends the Paraguay to the mouth of the Rio Negro, the outlet of the Bahia Negra, where the Bolivian boundary begins. As regards the Peruvian boundary, an agreement was reached in 1904 to submit the dispute to the arbitration of the president of Argentina in case further efforts to reach an amicable settlement failed. The provisional line, representing the Brazilian claim, begins at the termination of the Bolivian section (the intersection of the 11th parallel with the meridian of 72° 26' W. approx.) and follows a semicircular direction north-west and north to the source of the Javary (or Yavary), to include the basins of the Purús and Juruá within Brazilian jurisdiction. The line follows the Javary to its junction with the Amazon, and runs thence north by east direct to the mouth of the Apaporis, a tributary of the Yapurá, in about 1° 30' S. lat., 69° 20' W. long., where the Peruvian section ends. The whole of this line, however, was subject to future adjustments, Peru claiming all that part of the Amazon valley extending eastward to the Madeira and lying between the Beni and the east and west boundary line agreed upon by Spain and Portugal in 1750 and 1777, which is near the 7th parallel. With regard to the section between the Amazon and the Apaporis river, already settled between Brazil and Peru, the territory has been in protracted dispute between Peru, Ecuador and Colombia; but a treaty of limits between Brazil and Ecuador was signed in 1901 and promulgated in 1905. The boundary with Colombia, fixed by treaty of April 24, 1907, follows the lower rim of the Amazon basin, as defined by Brazil. The Colombian claim included the left bank of the Amazon eastward to the Auahy or Avahy-paraná channel between the Amazon and Yapurá, whence the line ran northward to the Negro near the intersection of the 66th meridian.