{illust. caption = FIG. 1.}
the highest daily record for speed. The results of our practice are graphically shown in Curve A of Fig. 1. As shown in that curve for the first day our average speed was only forty-two combinations per minute, but for the thirtieth day our average was seventy-four combinations per minute, We did not quite <p 225> double our speed by the practice, and we made but little improvement in accuracy. The most rapid gain was, as anticipated, during the first few days. We made but little progress from the sixteenth to the twenty-third day, and also from the twenty-fourth to the thirtieth day.
Of the six persons practicing addition, five of us also practiced the making of a maximum grip with a thumb and forefinger. Just before beginning the adding each day this maximum grip (or pinch) was exerted once a second for sixty seconds, first with the right hand and then with the left. Likewise at the completion of the addition sixty grips were taken by the right hand and sixty by the left. The total pressure exerted by each individual in the 240 trials (four minutes) was then recorded and expressed in kilograms. The result of the experiment is shown in curve B of Fig. 1. The average total pressure for each of the five persons was for the first day 620 kilograms; for the twenty-fourth day 1400 kilograms. Our increase was very rapid for the <p 226> first few days, and no general slump was encountered till the last week of practice. In one particular our results in the test on physical strength were not anticipated—we did not suppose that by practicing four minutes daily for thirty days we could double our physical strength in any such a series of maximum grips with the thumb and forefinger.
It is a simple matter to measure day by day the accomplishment of one learning to use the typewriter. All beginners who take the work seriously and work industriously pass through similar stages in this learning process. Figure 2 represents the record for the first eighty- six days of a learner who was devoting, in all, sixty minutes daily to actual writing. The numbers to the left of the figure in the vertical column indicate the number of strokes (including punctuations and shifts) made in ten minutes. The numbers on the base line indicate the days of practice. Thus on the ninth day the learner wrote 700 strokes in the ten minutes; on the fifty-fourth day 1300 strokes; on the eighty-sixth day over 1400 strokes. <p 227>
Figure 3 represents the results of a writer of some little experience who spent one hour a day writing a special form of copy.
In this curve it will be observed that the
{illust. caption = FIG. 2.}
increase in efficiency was very great during the first few weeks, but that during the succeeding weeks little improvement was made.—BOOK, W. R, ``The Psychology of Skill,'' p. 20. <p 228>
The progress of a telegraph operator is determined by the number of words which he
{illust. caption = FIG. 3.}