530 



Proceedings of the Boyal Irish Academy. 



went on repeating over and over again. I plotted curves for many 

 yards of "svaUdng and found this to be always the case. 



Tlie tliixd curve B may be taken as representing the average 

 variation of velocity, and I here give some of tbe ordinates by which 

 the curve was obtained. From these can be clearly seen the way in 

 which the vibrations for the steps repeat themselves. The length of 

 the ordinates are given in tenths of an inch, and are obtained Ly 

 counting the number of "strokes" in each wave-length. As men- 

 tioned previously a "stroke" is taken to be the distance from the 

 beginning of one dot to the beginning of the next. Each " stroke " 

 is given on the curve the value of one-tenth of an inch, and a wave- 

 length the one-half of an inch. The velocity is plotted vertically and 

 the time horizontally in the Plate. Half an inch represents the one- 

 nineteenth of a second. The fourth curve on the Plate shows varia- 

 tions from mean. 



It will be observed that the walker whose velocity is here recorded 

 walked more uniformly with his right foot than with his left. Thi& 

 fact is even more marked in other cases than in the particular case 

 here mentioned. 



Ordinates in 

 tenths of 

 an inch. 



Difference 

 of Or. 



Ordinates in 

 tenths of 

 an inch. 



Difference 

 of Or. 



0-00 





— 



71-50 



. 





4-25 



6-00 



. 



. 6-00 



76-50 



. 





500 



12-00 

 18-00 



j left heel comes |g.^^ 

 to ground . ) 



6-00 



81-25 

 87-25 

 93-25 



left comes to 

 ground 



) 



4-75 

 6-00 



6-00 



2300 





5-00 



99-25 



, 



600 



27-50 





4-50 



104-25 



. 





5-00 



31-50 





400 



108-75 







4-50 



35-25 





3-75 



112 75 







4-00 



40-25 





500 



117-75 







500 



46-25 





. 600 



122-75 







5-00 



52-00 

 57-75 



mght heel comes , 

 |to ground . j 



5-75 



128-50 

 134-50 [ 

 14000 ( 



right comes to 

 ground . 



J 



5-75 



6-00 

 5-50 



62-75 





5-00 



14500 



. 





500 



67-25 



. 



4-50 



149-50 







4-50 



Xow the left heel was put on the ground between 600 and 1200, 

 so here the left step begins. The right step begins at about 52-00. 



