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