128 MOVEMENT 



and thereby demonstrating its importance, it would 

 be as well to briefly sum up the results of other 

 methods. Such a review is the more necessary, 

 because chronophotography has nothing to do with 

 other methods, its application only becomes of real 

 value when mechanical methods can no longer be 

 employed. 



Speed of Different Paces in Man, Relationship between 

 the Frequency and Length of Stride. — A man in walking 

 or running covers at each stride a certain amount of 

 ground, and the more steps he takes in a given time 

 the greater is the total distance he covers. Similarly, 

 if the stride is increased, but the number kept the 

 same, the distance will be proportionately greater. 

 Speed, therefore, depends on two factors : the length 

 and frequency of the stride. Now, the brothers 

 Weber enunciated, as the result of their studies, that 

 the length of stride became greater as the frequency 

 increased ; a slow, processional step, for instance, being 

 shorter than one executed at a greater rate. If this 

 were the invariable law, the march of troops might 

 be indefinitely accelerated by quickening the time of 

 the drums or trumpets which regulated the pace. But 

 our experiments showed that this theory of the brothers 

 Weber was only correct up to a certain point, namely, 

 until the step was so quick that it amounted to a run, 

 and after that point was reached the rate of progression 

 soon diminished. Our experiments were made in the 

 following manner : — 



Being fully persuaded that, if one wanted to estimate 

 exactly the average length of stride, it Avas necessary 

 to carry out the experiments on a long track, we 

 laid out at the Physiological Station a circular and 

 perfectly horizontal course, five hundred metres in cir- 

 cumference ; a telegraph wire ran all the way round 

 the track, and the posts were placed at intervals of 



