228 KANSAS UNIVERSITY SCIENCE BULLETIN. 



was used with the thumb ergograph than with the larger 

 apparatus. It might be expected that if physical fatigue af- 

 fects mental ability by virtue of the circulation of fatigue 

 products from the working muscle, that the effect of the 

 thumb ergograph would not be so great. 



The influence of these two types of work is not very clear in 

 the results obtained. The differences in speed and accuracy 

 are not very great or constant. De. increases speed after rest 

 twice and decreases it an equal number of times, but decreases 

 accuracy three out of four times. In the two work series he 

 has increased speed a little on the average, and increased ac- 

 curacy slightly after the thumb exercise. Variations from day 

 to day lead to little hope that any influence of physical fatigue 

 can be recognized in his results. Even the big average increase 

 in speed after rest is made in spite of two decreases out of four 

 tests. An average of the per cent of increase or decrease in 

 both speed and accuracy computed from Table II& gives 102.5 

 per cent after rest, 99 per cent after thumb exercise, and 

 101.2 per cent after body exercise. Neither De. nor Co. show 

 the decrease in mental ability after twenty minutes' rest that 

 is indicated by Ba.'s results. Co. has consistently increased 

 speed after the thumb exercise, though accuracy is increased 

 but twice and decreased an equal amount the other two times. 

 He has not been able to produce an average increase after the 

 body exercise, though he was as liable to increase as to de- 

 crease. 



Just how fatigued either De. or Co. might have been would 

 be difficult to estimate. Both were normally developed men, 

 but they certainly found the work difficult. It is believed that 

 each worked conscientiously. If he did so, he must have been 

 greatly fatigued, in the arm when using the thumb ergograph, 

 and more generally in the legs and shoulders when using the 

 larger apparatus. 



The results from Do. do not vary materially in speed. This 

 may be due to the method employed. It will be remembered 

 that he conducted the tests alone, and used a stop watch to 

 determine the fifteen-minute period. The problems were also 

 mimeographed on letter-size paper, in place of on numerous 

 narrow slips as in the other experiments. Both of these 

 variations when taken together might influence the subject's 

 speed. Though the number of problems performed in a period 



