591.1 178 



IV. 



A RowiiiQ; Indicator.' 



IT is curious that, in a pastime which so readily lends itself to 

 experiment as rowing, httle has yet been done to investigate 

 many questions of interest to the physiologist, as well as to the 

 oarsman. Such researches as have hitherto been made have 

 generally been carried out without the aid of special apparatus, and 

 have in consequence been very indirect. 



The valuable researches made in Oxford more than twenty years 

 ago by Dr. Parkes and Mr. Maclaren will serve as an example. 

 Their object was to ascertain the value of a "man-power" in rowing, 

 and they appear to have been received as the standard results on 

 the subject.- The resistance offered by the water to a racing eight 

 travelling through it was obtained by means of a dynamometer 

 attached to the tow-line dragging a loaded eight at a rate of 

 2-65 knots. Assuming the resistance to vary as the square of the 

 velocity, and that at racing speed an eight travels at 8*57 knots, a 

 calculation was made of the work expended by each member of the 

 crew in a given time. The two necessary assumptions are sufficient 

 to render this reasoning hazardous. The calculation, moreover, 

 neglects the fact that men and oars are very different to their equivalent 

 ballast in sandbags. First, there is very considerable wind-resistance 

 which the ballast does not set up. Any oarsman will realise the 

 meaning of this, remembering that, not only the body, but the oar — 

 and especially the blade in the swing forward — has to be reckoned 

 with. Secondly, a portion of the energy expended in rowing is 

 devoted to communicating kinetic energy to the water at the blade, 

 so that this experiment takes no account of the swirl or " wash " left 

 behind in the water. 



The " Indicator" (Fig. i) affords a means of directly measuring, not 

 only the whole work done by any particular oarsman, but also of the 

 way in which the work is done. In general principle the instrument 

 is similar to the ordinary steam-engine indicator, but the diagram 

 obtained is necessarily rather more complicated than the familiar 

 " indicator diagrams." 



' From a paper read before the Oxford University Junior Scientific Club, 

 November 15, 1895. 



^Haughton's " Principles of Animal Mechanics." 



