[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.