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Author notes

1The following investigation was made with the co-operation and advice of a circle of inquirers interested in psychological science, among whom should be mentioned, in the present connexion, Mr. J. Sully and Mr. Carveth Read but especially Mrs. S. Bryant, D. Sc., who obtained the results from the North London Collegiate School and make many valuable suggestions both in the part of the investigation now presented and that still in hand.