DOCKERAY : PHYSICAL FATIGUE AND MENTAL EFFICIENCY. 205 



Tables la and lb show the results obtained from three sub- 

 jects. Ba. and Da. were strong, healthy men, accustomed to 

 all sorts of gymnastic exercises, including running, swimming 

 and tumbling. Ca. was decidedly of the opposite type, and un- 

 accustomed to any sort of robust exercise. Accordingly the 

 same physical work done by him should represent more fatigue. 

 The physical work done by Ca. and Da. consisted in a uniform 

 exercise with the ordinary wall machine of the gymnasium. 

 The subject stood with feet together and bent the back until 

 the hands were on a level with the knees. From this position 

 he rose to the erect position with the hands above the head. 

 This movement was repeated thirty times per minute for from 

 five to twenty minutes. The weight varied as indicated in 

 Table I. Ba. ran various distances on the indoor track. These 

 distances were not run at the subject's best speed, but at a 

 fairly fast rate, which did not vary materially throughout the 

 interval. This uniformity was maintained by the subject 

 setting a standard rate which he considered almost his best 

 for the distance to be run. At the end of each lap he was 

 informed as to whether he had run faster or slower than the 

 standard that had been established. 



MULTIPLICATION TEST. 



It was soon found that for most subjects at our disposal the 

 simple addition of single figures was inclined to become so 

 automatic that it was doubtful if it required enough attention 

 to be considered a good test. Frequently a subject would re- 

 port that he heard conversation in the adjoining rooms, but 

 did not feel disturbed in his work. He might even give slight 

 attention to other subjects without affecting the results suffi- 

 ciently to be detected in the records. For this reason it was 

 considered best to substitute a test that would demand the 

 most careful attention on the part of the subject, and at the 

 same time would not require elaborate apparatus. After the 

 consideration of several tests "cross multiplication" was 

 chosen. The subject was given a series of problems of two or 

 three place numbers, one below the other (the digits 1 and 

 were never used), and instructed to multiply as rapidly as 

 possible and still be accurate. He was allowed to record the 

 partial final product as it was obtained. That is, in such 



