502 REFERENCES

[129] Burt, C. (1939), 'The Factorial Analysis of Emotional

Traits,' Character and Personality, VII, pp. 238-54, 285-99.
[130] Davies, M. (1939), 'The General Factor in Correlations be-
tween Persons/ Brit. J. Psych., XXIX, pp. 404-21.
[131] Tryon, R. C. (1939), Cluster Analysis (Chicago: University

Press).
[132] Thomson, G. H. (1939). The Factorial Analysis of Human

Ability (London : University of London Press).
[133] Eysenclc, H. (1939), 'Critical Notice of "Primary Mental

Abilities/5' Brit. J. Educ. Psych., IX, pp. 270-5.
[134] Cast, B. M. D. (1939), 'Efficiency of Different Methods of

Marking/ ibid., IX, pp. 257-69, X, pp. 49-60.
[135] Vernon, P. E. (1939), c Educational Abilities of Training

College Students/ ibid., pp. 233-50.
[136] Stephenson, W. (1939), * Two Contributions to the Theory of

Mental Testing/ Brit. J. Psych., XXX, pp. 19-35* 23°~47-
[137] Thomson, G., Spearman, C., Stephenson, W,, and Burt, C.

(1939), Symposium on ' The Factorial Analysis of Ability/

ibid., pp. 71-108.
[138] Burt, C., and Stephenson, W. (1939), ' Alternative Views

on Correlations between Persons/ Psychometrikti, IV,

pp. 269-82.

[i39]Vernon, P. E. (1939), The Measurement of stlililm (Lon-
don : University of London Press).

Note.—The foregoing references mainly cover work that is easily
accessible, and easily intelligible, to the English student. The more
recent issues of the American journal Psycbometrika contain articles
of special interest to the advanced mathematical student; but
unfortunately—particularly at the present moment—-they are not
readily obtainable in this country. Technical articles on factor-
analysis have also appeared in recent numbers of the Proceedings
of the Royal Society of Edinburgh, The relevant German work on
matrix-algebra should be familiar to senior research workers
who propose to study the mathematical aspects ; the more im-
portant references are summarized in [74] and [8l], For the
beginner the best mathematical introduction is [84] chap* I* He
should then proceed to [132]. A revision of his school know-
ledge of determinants and an occasional reference to the earlier
chapters of [15], [26], [65], or [73] will be helpful in elucidating
' the commoner terms and theorems.