344 REPORTS ON THE STATE OF SCIENCE, ETC. 
Cost of Cycling at Varied Rate and Work.—Report of Committee 
(Professor J. S. Macponaup, Chairman; Dr. F. A. DurFriezp, 
Secretary). (Drawn up by the Secretary.) 
Emptoyine the experimental procedure indicated in last year’s report of the British 
Association! the research on the ‘ Cost of Cycling at Varied Rate and Work’ has been 
carried out throughout the year, and data from the subject ‘ Harrison,’ there alluded to, 
have been amplified to provide a series of figures representing the metabolism of 
cycling at three different rates—z.e. forty, sixty-three and eighty-five revolutions a 
minute. On the bicycle ergometer, with the rope-brake acting on the hind-wheel, 
mechanical work was performed at five selected levels—O, -05, ‘10, -15, and -20 h.p.— 
the lowest being obtained without the application of a brake, and therefore simply 
represents the ‘ cost of movement’? alone, with possibly a trifling allowance to be made 
for the internal friction of the cycle. 
These results and also those upon another subject (J. McHugh)—already communi- 
cated to the Physiological Society *—appear when plotted as three straight lines ; the 
dotted ones represent the results upon Harrison and the unbroken thick lines those 
upon McHugh. ‘The ordinate is the brake-power in Kals per minute, and the abscissa 
the metabolism in the same units, calculated from the respiratory exchange. 
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METABOLISM wKALS p.m. 
In both cases it is clear that a certain expenditure of energy is involved in the move- 
ments of the limbs, and is represented in the chart by the distance measured along the 
abscissa from the zero to the point where the particular line cuts it. A further expen- 
diture, indicated by the slope of the lines, represents the performance of external work. 
For each subject the metabolic expenditure is directly proportional to the external 
work done, and the efficiency therefore is constant, not only at one rate but at all 
rates, since the lines are practically parallel. The position of the lines on the abscissa is 
indicative of a considerable difference in the cost of movement in the two cases, and as 
far as these two subjects are concerned it is less with the subject of smaller body weight 
(Harrison 64:4 Kgm., McHugh 74:2 Kgm.), a conclusion previously arrived at and 
elaborated by Professor J. 8. Macdonald in his ‘ Man’s Mechanical Efficiency in Work 
Performance.’ Another person on whom work is still being continued, has yielded 
somewhat unexpected results; for although his body weight is only 51 Kgms. his figures 
lie intermediate between those of Harrison and McHugh. Whether this peculiarity is 
capable of some other explanation or whether there is an optimal weight for move- 
ment is a question which will necessitate further work before any decision is arrived at 
