272 LIGHT SCIENCE FOR LEISURE HOURS. 



Thus the Oxford stroke takes a perceptibly shorter 

 time than the Cambridge stroke ; it is also, necessarily, 

 somewhat shorter in the water. One would, therefore, 

 say it must be less effective. Especially would an 

 unpractised observer form this opinion, because the 

 Oxford stroke seems to be much shorter in range than 

 it is in reality. There we have the secret of its 

 efficiency. It is actually as long as the Cambridge 

 stroke, but is taken in a perceptibly shorter time. 

 What does this mean but that the oar is taken more 

 sharply, and, therefore, much more effectively, through 

 the water ? 



Much more effectively so far as the actual con- 

 ditions of the contest are concerned. The modern 

 racing outrigger requires a sharp impulse, because it 

 will take almost any speed we can apply to it. It 

 will also retain that speed between the strokes, a 

 consideration of great importance. The old-fashioned 

 racing-eights required to be continually under pro- 

 pulsion. The lightning-feather was a necessity in 

 their case, for between every stroke the boat would 

 lag terribly with a slow-feathering crew. I do not 

 say, of course, that the speed of a light outrigged 

 craft does not diminish between the strokes. Any- 

 one who has watched a closely contested bumping- 

 race, and noticed the way in which the sharply cut 

 bow of the pursuing boat draws up to the rudder of 

 the other as by a succession of impulses, although 

 either boat seen alone would seem to sweep on with 

 almost uniform speed, will know that the motion of 



