1898] SOME MORE ROWING EXPERIMENTS 95 
The author regrets that up to the present the only experiment in a 
racing eight was on an Oxford ‘ Torpid’ in its early days of practice. 
He suspects that during a race of eight to ten minutes’ duration the 
power would vary between °3 and ‘7 H.P. 
The figure given in the sixth column of the table is of some 
importance, since it roughly indicates the form of the stroke. This 
coefficient, found by dividing the mean pull during the stroke by 
the greatest pull, gives a measure of the uniformity of the pull. 
If the usual coaching maxim of “getting the full work on at once 
and carrying it out to the finish,’ were literally carried out, the 
stroke diagram would become a rectangle, and the coefficient unity. 
It is, however, probable that the best results would not be 
obtained with a high coefficient, since the extra work done does not 
compensate for the additional fatigue, physical and nervous, involved 
in setting the muscles suddenly at their fullest tension. In addition 
to this physiological point there is the mechanical one that the 
efficiency of propulsion is greatest—other things being equal— 
when the oar is at right angles to the boat, since it is here that the 
smallest proportion of the work is devoted to generating kinetic 
energy in the water. 
This question of efficiency of propulsion by oars has been made 
the subject of experiment by the author. To determine this it is 
necessary to know, in addition to the information afforded by the 
indicator diagram, the point about which the oar is turning at 
every part of the stroke. Since the rowlock is moving forwards, 
and the tip of the blade backwards, some point between these is 
neither moving backwards nor forwards. This point may be called 
the Turning Point.!. A moment’s consideration will show that this 
point changes its position during the stroke, since the blade first 
encounters ‘dead’ water, so that the blade tip at first moves 
slowly, and the turning point is lower down the oar than a moment 
afterwards when the water has been set in motion. 
By attaching a float to different parts of the oar by a string, so 
that the float was immersed during the stroke, it was possible to 
estimate fairly accurately the mean position of the turning point, 
for which a position 36 inches above the tip of the blade was found, 
1e., a point only 3 inches above the top of the blade. This shows 
how comparatively slight is the motion given to the water, a point 
which will be more clearly brought out below. 
In August of last year the author made an attempt to arrive at 
more exact results on this point by taking a rapid series of photo- 
graphs of an oar in motion on the same plate, from a point vertically 
above the boat. Unfortunately, the only time available, about 3.30 
P.M, on a cloudy afternoon, was not an ideal one for exposures lasting 
1 Tt is clearly the projection of the ‘ Instantaneous Centre Locus’ on the oar. 
y; proj 
