Woodworth, R. S., 51, 56, 96. Woolley, H. T., 211. Word blindness, 63 f. Wundt, W., laboratory of, 4. X, instruction of, in reading, 71 ff. Zirbes, L., 211. ----- Footnote 1: ρ = 1 − 6ξ_d_^2/_n_(_n_^2 − 1) Resemblance equals one minus six times the sum of the differences (in rank) squared, over the number (of cases) times the number (of cases) squared, minus one. Footnote 2: ρ = 1 − 6ξ_d_^2/_n_(_n_^2 − 1) Formula explained, opposite page. Footnote 3: Thompson has recently shown that a coefficient of zero does not necessarily mean absence of relationship between two factors. There might be a strong influence making for negative correlation, and at the same time an equally strong influence making for positive correlation, which might, by just counterbalancing each other, produce a spurious effect of no connection at all, namely, a coefficient of 0.00. Footnote 4: A curious case of negative correlation between cancellation and other tests has been reported by McCall (see references). Footnote 5: “Insanity” and “dementia” seem to be synonymous, as used by Hart and Spearman. But in American texts “dementia” is limited to mean intellectual deterioration. Footnote 6: Because of the probabilities in die-casting, every single value for red would have the same median value among the throws of yellow, which turn up in connection with it, if enough throws are made. This is not what happens in measuring mental traits. For any single value, high or low, in one function, the median of repeated measures in the other function is very different, for most traits, from the median for other values. Footnote 7: For explanation of technical terms see McCall’s _How to Measure in Education_. Footnote 8: This suggestion originated with a colleague of the present writer, who is working upon allied problems. Footnote 9: See Reference to Ladd and Woodworth. Footnote 10: It must be remembered that children and adults of almost any birthday age may be at this general intelligence level. Footnote 11: If alternates are counted instead of the four tests which directly involve reading or spelling, these IQ’s become 88, 85, 87, respectively. Footnote 12: For all practical purposes, IQ’s differing from each other by not more than 5 points are equal. Footnote 13: Fildes’ subjects ranged in birthday age from 9 to 16 years. In criticism it should be stated that correlation between IQ and ability to read cannot be clearly interpreted unless an array of birthday ages is given in conjunction. Fildes does not give such an array. Footnote 14: The substance of discussion under this topic is reprinted by courtesy of the _Teachers College Record_, from the issue of that journal for March, 1919. Footnote 15: Quoted by permission of the Atlantic Monthly Press. Footnote 16: Bidder died at 72. Footnote 17: