THE MECHANISM OE BICYCLES. 
407 
made some experiments the'other day with a view to finding out exactly how 
much thrust came upon the pedal in every different position of the crank and in 
fact, similar results were obtained by me to those obtained by M. Bonny. In 
this diagram (exhibiting the same) Big. 1, taking this © as the centre and these 
b 
the various radii of these curves as the different positions of the crank, those two 
curves the black and the dotted, show the effective thrust which I personally was 
able to exert upon either pedal respectively in every position, the radius vector in 
any position being proportional to the tangential, that is the effective thrust on 
the pedal, and the second diagram here, Fig. 2, shows these two put into one. 
It is curious, by the way, what a lot of difference there is between the right foot 
and the left. In this one, Fig. 2, the two thrusts in each position are added 
together and multiplied by the length of crank, inches, giving the total torque 
on the crank; and this black curve inside is the theoretical curve which should 
be given were the force applied direct from the hip and equal to my own weight. 
I was very much surprised ( I made these experiments fairly carefully) to find 
how very much more than my own weight I was thrusting on the pedals. These 
fairly well agree with the diagrams which Major von Donop showed us, except 
that this {a) being the front of the bicycle, the saddle being here fb), they are 
turned through an angle of about twenty degrees and of course those diagrams 
must have been taken with the rider sitting right forward over the pedals in the 
scorching position. 
