We have seen that a union of three separate qualities—intellect, zeal, and power of work—are necessary to raise men from the ranks.
Lehman (9) has recently expressed this same idea, as a result of a statistical study of the most productive years of intellectual workers:
Indeed, it is doubtful that genius is solely the fruit of any single trait. It is the belief of the writer that the fruits of genius are, on the contrary, a function of numerous integers, including both the personal traits of the individual worker, environmental conditions that are not too hostile, and the fortunate combination of both personal traits and external conditions.
As quantitative. Galton (6) was the first to place the study of genius on the basis of quantitative statement, so that comparisons might be made and vertifications be effected. Galton formulated the theory that genius (great natural ability) is nothing more nor less than a very extreme degree in the distribution of a combination of traits—"intellect, zeal, and power of working"— which is shared by all in various "grades" or degrees. Reasoning thus, Galton applied for the first time in human thought the mathematical concepts of probablity to the definition of genius.
Quetelet (13), drawing objects from congeries of known composition, had elaborated the form which the probabilities take of drawing a given combination. This form, with the law of deviation from the average governing it, is now, of course, a commonplace in psychological laboratories, so that it is hard to realize that when Galton made the mental leap from this curve to the abilities of men, no one had ever thought of human minds as "fitting" the curve drawn by Quetelet. Such a "fit" had already been thought of in connection with measurements of physique, and had been demonstrated for measurements of the shrimp (16) and for physical traits of persons. But that "natural ability" should be susceptible to the probability curve and "the curious theoretical law of deviation from an average" as length is among shrimps, or as circumference of the chest is among Scottish soldiers (as shown by Quetelet), was not conceived. With the modern methods of mental measurement it is easy enough to perceive the truth of this. But Galton was working in the dark, entirely without instruments of precision; and his table of frequency "for the classification of men according to their natural gifts" must be regarded as one of the most prescient statements in the history of social science.
Working with the tables devised by Quetelet, Galton proposed the tabular "classification of men according to their natural gifts" shown [below].
CLASSIFICATION OF MEN ACCORDING TO THEIR NATURAL GIFTS
GRADES OF NATURAL NUMBERS OF MEN COMPRISED IN THE SEVERAL GRADES OF NATURAL ABILITY, WHETHER IN RESPECT ABILITY, SEPARATED TO THEIR GENERAL POWERS OR TO SPECIAL APTITUDES BY EQUAL INTERVALS
Below Above Proportionate; In Each Million In Total Male Population of the United Kingdom, Say Average Average viz., One in of the Same Age 15 Millions, of the Undermentioned Ages 20-30 30-40 40-50 50-60 60-70 70-80 a A 4 256,791 651,000 495,000 391,000 268,000 171,000 77,000 b B 6 161,279 409,000 312,000 246,000 168,000 107,000 48,000 c C 16 63,563 161,000 123,000 97,000 66,000 42,000 19,000 d D 64 15,696 39,800 30,300 23,900 16,400 10,400 4,700 e E 413 2,423 6,100 4,700 3,700 2,520 1,600 729 f F 4,300 233 590 450 355 243 155 70 g G 79,000 14 35 27 21 15 9 4 x
All grades All grades below g above G 1,000,000 1 3 2 2 2 0 0