H.L. Gantt, Work, Wages and Profits, p. 116.

H.L. Gantt, paper 928, A.S.M.E., p. 342.

F.W. Taylor, Shop Management, para. 289, Harper Ed., pp. 127-128.

H.K. Hathaway, Engineering Magazine, April, 1911, p. 144.

W.D. Ennis, An Experiment in Motion Study, Industrial Engineering, June, 1911, p. 462.

C.S. Myers, M.D., An Introduction to Experimental Psychology, chap. V, p. 73.

G.M. Stratton, Experimental Psychology and Culture, p. 125.

William James, Psychology, Briefer Course, p. 171.

F.B. Gilbreth, Bricklaying System, chap. I, Training of Apprentices.

McClure's Magazine, May, 1911, Dec, 1911, Jan., 1912.

As a woodman's keenness of hearing.

M.W. Calkins, A First Book in Psychology, chap. III.

Stratton, Experimental Psychology and Culture, chap. VII.

Compare with an actor's learning a part.

As proved by experimenting with a six-year-old child.