Heat-production Associated with Muscular Work. 107 



performing it is soon discovered and adhered to when found, but with the 

 scanty work of the light brake many needless additional movements may be 

 performed without much personal inconvenience. On this ground I have 

 omitted his earlier experiments, which were of this kind. Now on similar 

 grounds, namely, that excessive movements were seen and commented upon 

 at the time, I have omitted two experiments with the lightest brake per- 

 formed by two other individuals. In both cases the appearances were so 

 marked that these subjects were requested to provide me with another 

 opportunity, and were kind enough to grant this. One of these repetitions, 

 however, fell unfortunately in the period of ambiguity of the brake, the other 

 coincides with the time of the altered brake and is recorded there. 



With these exceptions all the experiments of this type performed since 

 October, 1912, are summarised in the data given. Those experiments which 

 are quoted from an earlier date than this are selections satisfying the 

 conditions adhered to this year during this whole series of experiments, and 

 are taken from a time when I was experimenting with various revolution 

 rates and brakes as well as with modifications in handling the calorimeter. 

 As a matter of fact this process of selection has involved the exclusion of 

 only two experiments from amongst those which might have been available ; 

 one because the cycling was not continued sufficiently into the second hour 

 and the other because of a quite unusual difference between the temperature 

 of the entering and leaving air and between the temperature of the 

 laboratory and that of the calorimeter. In no case except that of Armstrong- 

 would the inclusion of these experiments have altered the general character 

 of the results obtained. 



Group A. — Experiments in which a maintained rate of 60 revolutions per 

 minute would have involved the performance of mechanical work on the 

 cycle at the rate of 13 kalories per hour (approximately 0'02 horse-power). 





Date. 



Weight.* 



Revolutions 

 per minute. 



Name. 



Heat produc- 

 tion, in kalories 

 per hour. 





1912. 



kgrin. 









I 



Nov. 13 



54 6 



59 -4 



Bennet 



160 



II 



„ 18 



58 -8 



60 -1 



Ward 



181 



III 



„ 21 



66 -7 



60 -1 



Sharrard 



209 



IV 



May 22 



55 7 



60 -7 



Briscoe 



169 



v 



„ 25 



61 -8 



59 -7 



Chapman 



184 



VI 



„ 30 



62 -0 



59 -8 



Duftey 



186 



Average heat production 182 kalories per hour. 

 Maximal aberrations from this average { * 13 .g cen ^' 

 * All weights given were taken with the subjects stripped. 



I 2 



