ABSTRACT
Consider FIG. 43 which gives the number of additions of a one-place to a one-place number made in five minutes on each of thirty days of practice by four adults (averaged) . It is clear that the gain in speed is greater for the first than for the second half of the practice. There is, in general, a negative acceleration shown by the parabolic form of the curve. Contrast this with FIG. 44, which gives the average practice curve for twenty-three women students in translating English text by replacing each letter by another in accordance with a specified 'key.' The gain in speed here during the last half of the practice is equal to, or a little greater than, that made during the first half. There is zero acceleration or a slightly positive acceleration.
