591.1 89 



Some More Rowing Experiments 



IN tin' autumn of 1895 the author designed an indicator for 

 recording the work done in a stroke of rowing. 1 The apparatus 

 replaced the front thowl of the rowlock, and consisted of a plate 

 turning with the oar, which pressed against it, about an axle to 

 which it was connected by means of another plate pivoted to the 

 first. 



The pressure of the oar tended to move the front plate back 

 towards the axle, this motion being resisted by a spring. The 

 movements of the plate, and consequently of the oar, were recorded 

 as a diagram on a horizontal card by a pencil connected with the 

 plate. This diagram afforded the information given by the familiar 

 steam-engine indicator diagram, and gave measures of the horse- 

 power of oarsmen, as well as interesting information with regard to 

 the way in which the work was done, showing the great differences 

 that existed between the style and stroke-forms of different oarsmen. 



The successful working of this simple instrument encouraged 

 the author in 1896 to attempt another, obviating the shortcomings 

 of the first. This latter, in addition to various mechanical imperfec- 

 tions, had the disadvantage of giving the diagram in curvilinear 

 co-ordinates, necessitating laborious measurement and reduction 

 before stroke form and work done could be estimated. 



Further, in testing a steam-engine it is customary to take 

 several diagrams during a run, by changing the card on which 

 the figures are being drawn. In a boat this is impracticable 

 without stopping the rowing. It will be seen that an important 

 part of the later machine is the automatic winding apparatus, where- 

 by the card changes itself. The author was recently interested in 

 having his attention called to a similar device which was being 

 introduced for the steam engine. 



The general principle of the former indicator, that of recording 

 the movements of a plate turning with the oar and pressed forward 

 by a spring, has been adhered to. In the photographs (Plate I.) 

 and diagram illustrating the action of the pencil and spring (Fig. 1) 

 the face A moves with the oar, and is connected with the axle B 



1 For a description of the instrument and results obtained, see Natural Science, vol. 

 viii., pp. 178-185, March 1896. 



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