PSYCHOLOGICAL PROGRAM AND TECHNIQUE. 



151 



ing and the standard weights. The average error, particularly in that 

 range which was commonly employed, which is from 35 to 70 kg., is 

 • usually less than ±0.2 kg. with the higher temperature, which was 

 more nearly the condition used under actual experimentation, as the 

 subjects desired to have the rooms in which they worked quite warm. 

 It was seen that no such discrepancies or errors between standard 

 weights and dynamometer readings were found in the case of this instru- 

 ment as those recorded by Kohs, and therefore our readings are given 

 without correction. With the exception of three occasions, the read- 

 ings were always made by the same individual. These times were: 

 the evening of December 19, Squad A; morning of February 3, after 

 the walking experiment. Squad A; and the records which were taken in 

 Springfield on May 21 and 22. 



Table 8. — Calibration to check the accuracy of the hand dynamometer used in this research. 



(7) Changes in Pulse-Rate Occasioned by Short Periods of Exertion. 



This was one of the morning measurements. A brief review of liter- 

 ature pertaining to pulse records of this sort and a description of 

 technique previously used has been given in another publication by 

 one of us under the convenient name of ''tetanus pulse, "^ Formerly 

 the changes in pulse-rate were produced by the subject's clenching his 

 fists and making the muscles of arms, legs, and trunk rigid for a given 

 period, after which he relaxed in a steamer chair as he had been pre- 

 vious to the exertion. From the standpoint of quick transitions from 

 rest to exertion, and from exertion to rest, no routine can be better, but, 

 as pointed out in the previous publication, much depends upon the sub- 

 ject for the amount of exertion actually put forth and in sustaining it 

 with some uniformity during the period. 



1 Miles, Carnegie Inst. Wash. Pub. No. 266, 1918, p. 92. 



