Man's Mechanical Efficiency in Work Performance. 397 



may somewhat unexpectedly disintegrate that quantity into terms of work 

 done and price paid. 



Turning then to the data of the two more recent groups of experiments, 

 B and D (loc. cit„ pp. 108, 109), it will be seen that four names, and not 

 more than four, are to be found in both groups, and so provide four 

 individual opportunities for a determination of efficiency by reference to 

 increments of work and heat production. Always speaking of these 

 subjects, Kemp, Kae, Bennett, Armstrong, in the same order, they may be 

 thought of as differing from one another in several ways which seemed to 

 tiave so little influence on the data that they were not mentioned in the 

 process of preliminary analysis. Thus their heights are different, respec- 

 tively 168-7, 171-8, 171-2, and 156-4 cm. Their "figures" are different, as 

 may be deduced from a comparison of these heights with .the cube roots of 

 their " stripped weights," their respective heights in these terms being, 

 4-26 W 1 ^ 4-37 W 1/3 , 4-50 W 1 / 3 , and 4-44 W 1 ' 3 ; from which it may be inferred 

 that Bennett was slender (4 - 5 W 1/3 ), whereas Kemp was sturdy (4-26 W 1/3 ), 

 and the other two were of intermediate types. The clothes worn weighed 

 respectively, 1*5, 1*0, 3'7, and 3 - 8 kgrm. ; the lighter clothes being the 

 " athletic exercise " garb of two medical students, the heavier the ordinary 

 clothes of two junior laboratory assistants. As a matter of fact, it is 

 ■difficult to control clothing and the attempt made was limited to the 

 supervision, and provision where necessary, of light shoes. Then the mean 

 rectal temperatures during that part of the experiments (second hour) 

 •covered- by the data were respectively, 36 - 6, 37'3, 37'0, and 37*7° C. ; the 

 mean surface temperatures, 29'8, 29"9, 3T8, and 34'0° C. More differences, 

 of less importance, could also be mentioned in terms of age, diet, and habit. 



First, taking the data from the Tables without correction, that is to say, 

 dealing with all four subjects as if they had each performed exactly the 

 •standard amount of work required, equivalent to 56 kalories in D, to 

 19 kalories in B, and therefore providing an increment of 37 kalories : 

 this increment is then compared with the measured increments of heat 

 production, which differ in the individual cases. 



Name. 



Weight 

 " stripped." 



Heat pro 

 G-roup D. 



duction. 

 Group B. 



Increment. 



Factors 

 of increment. 



(2) Rae 



(3) Bennett 



kgrm. 

 62 -1 

 60-5 

 54 -6 

 43 -7 



350 

 347 

 335 

 346 



128 

 212 

 193 

 177 



132 

 135 

 142 

 169 



37 x 3 -57 

 37 x 3 -65 

 37 x 3 -84 

 37 x 4 -57 



