192 THE HUMAN MOTOR 



The whole of the preceding researches, especially in view of 

 the yields of 24 and 24-6% obtained, by Atwater and his colla- 

 borators, Benedict and Carpenter, ( l ) lead to a value of at least 

 25% for the useful effect of the muscular energy of the legs. 



135. (c) Ascents of Mountains : -Walking. Dumas and Bous- 

 singault ( 2 ) quote an ascent of Mont Blanc, made in twelve hours, 

 which necessitated a dynamic expenditure of 2,425 Calories, that 

 is a net yield. 



4,810 X 65 OAO/ 

 = 2,425 X425 =3 % a PP roximatel y- 



The height of Mont Blanc is 4,810 metres, and the weight of 

 the subject was 65 kilogrammes. Fick and Vislicenus, in their 

 ascent of the Faulhorn (1,956 metres) calculated a yield of 50%, 

 but on very doubtful data ( 106). 



In walking, Katzenstein ( 3 ) obtained a dynamic expenditure 

 of 1-957 c.c. of oxygen per kilogrammetre, that is, 



0-001957 x 4-90 X 425 = 4-075 kgm. 

 From this : 



R = = 25% approximately, 



a result which agrees with the preceding ones. However, 

 Frentzel and Reach, ( 4 ) studying six different subjects on climbing 

 expeditions, obtained an average of 32% with a minimum of 28% 

 and a maximum of 36%. 



Undoubtedly, the lower limbs have a peculiar impulse which 

 reduces their expenditure of energy if they are not caused to 

 exceed their natural effort and their normal speed. In ascending 

 an inclined plane (see 298) R has been found to be 29-40% 

 approximately. ( 5 ) 



136. (d) Use of the Muscles of the Arm. There are very few 

 good experiments on the useful work produced by the muscles 

 of the arm. The use of the ergograph ( 119) does not allow the 

 separation of motor from resistant work, and the expenditure 

 therefore, refers to a heterogeneous, mechanical whole. An ex- 

 ception must be made in favour of Hall's ( 6 ) ergograph, which 

 makes this distinction, although the use of this ergograph is 

 restricted. 



(*) Benedict and Carpenter (Bulletin, No. 208, p. 39; 1909). 



( 2 ) Dumas and Boussingault, Essai de Statique des etres Organists, 1344. 



( 3 ) Katzenstein (Pfluger's Archiv., vol. xlix.~, p. 330, 1391). 



( 4 ) Frentzel and Reach (Ibid., vol. Ixxxiii., p. 477, 1901). 



( 6 ) J. Amar (Comptes Rendus Sciences, May, 1911, p.p. 13-27). 

 ( 6 ) W. S. Hall, Experimental Physiology, 1904, p. 227. 



