THE ECONOMY OF MOVEMENT. 13 



this, so to speak, " pendular " hypothesis, amongst others 

 Marey, who made brilliant observations with all the advantage 

 of a " technique " supplemented by the developments of 

 instantaneous photography. Marey cites one particular point 

 in his observations with regard to the variation of the length 

 of step as if conclusively hostile to the Webers' opinion, and 

 this particular point has been made much of by everyone who 

 has been influenced, as in fact all have been influenced by the 

 general value of Marey's methods. The point is that at a 

 certain "intermediate rate" of walking the change in the 

 length of step alters from one mode to a new one. There is thus 

 a certain nodal point in Marey's observations, whereas in 

 Webers' opinion there is a very definite nodal rate, the 

 "pendular rate" of the limb. 



Now, it has interested me to plot out, and attempt further 

 analysis of the data collected by the Webers, and I have found 

 that they may be arranged on a plan not in any way alluded 

 to by the Webers, most probably never considered by them. 

 I intend to publish the details of this plan in a separate paper, 

 and for present purposes their exact nature is of small 

 interest, the pith of the matter, however, is this, that the 

 Webers' data can be shown to illuminate the point raised into 

 importance by Marey. Thus, Marey was evidently unaware 

 that his observation referred to a particular rate of great 

 interest in these classical data of Webers, of great interest in 

 so far as, in the case of their subject, it actually coincides with 

 his " pendular rate." With the assistance of Mr. A. Wallis I 

 have investigated this variation in step in a number of subjects, 

 and have reasons for saying that the mode of variation is not 

 in all cases the same, although in each case definitely regular 

 modes of variation are obviously present. It is not to be 

 expected, and is not as a matter of fact the case, that the 

 coincidence is the same as in the Webers' data. However, of 

 all cases it seems to be true that the " nodal point " referred to 

 as marking an interesting intermediate rate, is also the mark 



