SECTIONAL TRANSACTIONS.—I. 481 | 
Tuesday, September 18. 
20. Prof. J. S. Macponap, F.R.S.—Cycling at a Constantly Main- 
tained Speed with Varied Brake. (Carried out with the help 
of the late Mr. A. Wallis.) 
These experiments form a continuation of experiments previously made 
by direct calorimetrical methods (Proc. Roy. Soc., B., vol. 89, 1916, p. 394, &c.). 
They were carried out by indirect calorimetry (Douglas Bag and Haldane’s Gas 
Analysis method) over the greater range made possible by this change. The 
results confirm those already reported. 
21. Prof. J. 8. Macponatp, F.R.S.—Variation of Length of Step 
in Walking. 
Previous observations have been made on the length of step by the Webers, 
by Marey, and by others. These new experimental data are in agreement in 
showing a definite relationship between step and velocity, which is departed 
from notably at a certain higher range of velocity. At this maximum the 
step-length fails to undergo any further increase : below it the relationship in 
5 : 8 : : anaes 
each case is approximately = =k when & is constant in each individual case 
and has a definite relationship to the height of the individual in different 
individual cases. 
22. Miss Marcarer S. Macponaup and Prof. J. S. Macponatp, 
F.R.S.—The Cost of Walking. 
Experiments have been made on a number of subjects—male and female, 
adult and young. The results are generally capable of being plotted out best 
2 
in relation to v%. Utilising the observation that = is almost a constant, 
attempts have been made to analyse these results in the general form 
ELS ar La vy ‘ea 
v s \v 
and a general formula developed in which it has been found possible to insert 
“pendular characteristics of length of time,’ involving the length of the leg 
and its square root. In this general formula the area of the surface of the 
body is inserted in unconventional fashion (a) as determining a cooling factor 
which reduces the sum due to basal metabolism and to vertical movement, and 
(6) as the measure of ‘ wind resistance’ impeding progression and increasing 
the sum due to movement. This procedure follows the line suggested by the 
cycling experiments. ‘ 
23. Dr. T. W. Wapsworty, Prof. J. S. Macponatp, F.R.S., and 
Mr. Geo. Macponaup.—Variation in Character of Step. 
Observations have been made on the pressure exerted by the heel in walking, 
and on the time occupied by heel-pressure, also in cruder fashion on the lift 
of the body at each step. 
. Dr. F. A. Durrie~p.—Cycling at Varied Rate and Work. 
Experiments have been made with a modified ‘rope brake’ ergometer, 
devised so as to ensure maintenance of the load as exactly as possible, and 
he simultaneous operation of taps on the Douglas-bag apparatus. Two sub- 
jects have been utilised. In one case the results are such as to justify the 
statement that each rate of movement determines a base line of metabolism 
ipon which the value of the brake erects a directly proportional increment. 
In the other case the statement of results is evidently not so simple, and experi- 
nents are being continued to study the significance of the requisite modification 
n statement. 
KE 
