"632 



ANNUA!, REPORT SMITHSONIAN INSTITUTION, 1911. 



We therefore now know that the limit of speed is controlled by two 

 factors : 



(1) Physical endurance, owing to the expenditure of work occur- 

 ring at an increasing rate as the speed is increased. 



(2) The physical impossibility of giving a reciprocating movement 

 to the legs quicker than a certain limited period of time. 



I have prepared a chart (fig. 2) which shows the maximum recorded 

 velocities of man's progression in walking and running. The speeds 

 are set up as vertical ordinates, and the abscissae represent the dis- 

 tances over which the respective speeds were maintained. It will be 



40 50 



MILE.5 



Fig. 2.— Speed records for human muscular effort. 



seen that the maximum speed of walking is about 9 miles an hour 

 for a short distance, but when the long distance of 100 miles is covered, 

 the quickest rate recorded falls to 5| miles an hour. For running, 

 the quickest speed which I have mentioned, viz, 21 § miles an hour 

 for 100 yards, falls to 7^ miles an hour as the average speed for a dis- 

 tance of 100 miles. 



We do not know the speed of the original historical run from Mara- 

 thon to Athens, but we do know that Dorando ran the modern Marathon 

 from Windsor Castle to the stadium at Shepherd's Bush, a distance of 



