REFERENCES [i] Lagrange, J. L. (1759), (Euvres, L, pp. 1-20. [2] Gauss, C. F. (1823), Werke, IV, pp. 26-55. [3] Sylvester, J. J. (1851), Collected Works, I, pp. 221 W seq. ; IV, pp« no ^ j^. [4] Bravais, A, (1846), "Analyse mathematique sur les prob- abilltis des erreurs de situation d'un point,' AcaL des Sciences : Memoir es present es par divers savants, IP Serie, IX, pp. 255-73. [5] Galton, F. (1888), 'Correlations and their Measurement/ Proc* Roy. Soc.y XLV, pp. 136-45. [6] Cattell, J. McK. (1890), < Mental Tests and Measurements/ Mind, XV, pp. 373-80. [7] Pearson, K. (1896), * Regression, Heredity, and Panmixia/ Phil Trans. Roy. Soc., Ser. A, CLXXXVII, pp. 253-318. [8] Yule, G, U, (1897),i On the Significance of Bravais' Formula for Regression, etc., in Skew Correlation/ Proc, Roy. Soc., LX, pp. 477-89. [9] Wissler, C. (with J. M. Cattell and R. C. Farrand) (1901), 4 The Correlation of Mental and Physical Tests/ Psych, Rev. Mon. Supp., HI. [to] Pearson, K. (1902), * On the Influence of Natural Selection on the Variability and Correlation of Organs/ Phil. Trans. Roy. Soc.9 CC, A> pp. 1-66, [n] — (*9°4)) ' Inheritance of Mental and Moral Char- acters in Man/ Biometrika, III, pp. 131-90. [12] Spearman, C. (1904), * General Intdligence Objectively Determined and Measured/ Am*J. Psycb., XV, pp. 201-93. [13] Krueger, F,? and Spearman, C. (1906), 'Die fcorrelation zwischen verschiedenen geistigen Leisttingsfahigkeiten/ 2./ Psych,, XLIV, pp. 50-114. [14] Weldon, W. F. R. (1906), * Inheritance in Animals and Plants/ ap* Strong, T, B. (ed.) Lectures on the Method, of Science. [15] B6cher? M. (1907), Introduction to Higher Algebra (New York: Macmillan), [16] Burt, C, (1909), * Experimental Tests of General Intelligence/ Srit. y. Psych,, III, pp. 94-177- * 495