[127] Compare observations of Georg Schweinfurth, The Heart of Africa, Vol. I, pp. 312-313. London, 1873. [128] Nott and Gliddon, Types of Mankind, p. lvii. Philadelphia, 1868. [129] D.M. Wallace, Russia, pp. 151-155. New York, 1904. [130] Thucydides, Book I, chap. II. [131] Strabo, Book II, chap. III, 7. [132] McGee and Thomas, Prehistoric North America, pp. 408-414, Vol. XIX of _History of North America_, edited by T.N. Thorpe. Philadelphia, 1905. [133] Hodgkin, Italy and Her Invaders, Vol. II, p. 214. Oxford, 1892. [134] Sir John Lubbock, Prehistoric Times, p. 587. New York, 1872. [135] D.G. Brinton, The American Race, pp. 116-119. Philadelphia, 1901. [136] O.T. Mason, Primitive Travel and Transportation, pp. 249-250. _Smithsonian Report_, Washington, 1896. [137] Thucydides, Book I, chap. II. [138] Edward A. Boss, Foundations of Sociology, pp. 359-363, 386-389. New York, 1905. [139] D.G. Brinton, Races and Peoples, pp. 73-75. Philadelphia, 1901. [140] John Richard Green, The Making of England, Vol. I, pp. 9-11, 45-46, 52-54, 57, 62. London, 1904. [141] James Bryce, The Migration of the Races of Men Considered Historically, _Scottish Geographical Magazine_, Vol. VIII, pp. 400-421, and _Smithsonian Report_ for 1893, pp. 567-588. [142] Caesar, _De Bello Gallico_, Book II, chap. 29. [143] Motley, Rise of the Dutch Republic, Vol. I, p. 5. New York, 1883. [144] John Richard Green, The Making of England, Vol. I, p. 46. London, 1904. [145] Hodgkin, Italy and Her Invaders, Vol. V, pp. 99-101. Oxford, 1895. [146] _Ibid._, Vol. V, pp. 156-157. [147] Hodgkin, Italy and Her Invaders, Vol. II, pp. 107, 195. Oxford, 1892. [148] _Ibid._, Vol. II, pp. 219-223, 230. [149] W.Z. Ripley, Races of Europe, pp. 276-277. New York, 1899. [150] Hodgkin, Italy and Her Invaders, Vol. II, pp. 214-219. Oxford, 1892. [151] Ratzel, History of Mankind, Vol. II, p. 296. London, 1896-1898. [152] McGee and Thomas, Prehistoric North America, pp. 408-412, Vol. XIX of _History of North America._ Philadelphia, 1905. [153] Hugh R. Mill, International Geography, p. 858. New York, 1902. [154] Roscher, _National-Oekonomik des Ackerbaues,_ pp. 44-48. Stuttgart, 1888. [155] Cyrus Thomas, The Indians of North America in Historical Times, p. 261. Vol. II of _History of North America,_ Philadelphia, 1903. [156] Roosevelt, Winning of the West, Vol. I, pp. 134-135, 250. New York, 1895. Justin Winsor, The Westward Movement, p. 16. Boston, 1899. [157] Eleventh Census, _Report on the Indians_, p. 54. Washington, 1894. [158] _Ibid._, p. 531. [159] Hans Helmolt, History of the World, Vol. III, p. 411. New York, 1902-1906. [160] Edward John Payne, History of the New World Called America, Vol. II, pp. 57-58. Oxford, 1899. [161] _II Kings_, Chap. XVII, 6-24. [162] W.Z. Ripley, Races of Europe, pp. 432-434. New York, 1899. [163] Hans Helmolt, History of the World, Vol. V, pp. 353-354. New York, 1902-1906. [164] _Ibid._, Vol. VI, p. 15.