886 
THE MECHANISM OF BICYCLES. 
to bear in mind that I am influenced by two things; the first is that 
feeling that I am much indebted to the various owners for the loan of 
their machines, I do not think it would be fair, on my part at any 
rate, to condemn portions of their mechanism which might appear at 
first sight to be unsatisfactory, without having first given them a 
thorough trial; some were certainly sent in time for me to try, but 
the trials were not very satisfoctory owing to my apparently not being 
(to use a lady’s shopping expression) “ stock size,” and it is useless 
trying a machine if it does not fit you. 
The second thing is that it was stated in this theatre about five 
weeks ago that bicycle companies are extremely fond of litigation. I 
am not. 
I must remind you that all the gear cases have been taken off the 
machines and in certain cases diagrams are printed in order to show 
the parts more clearly. 
A bicycle is a machine arranged so as to evolve f work 9 from the 
power received into it from the weight and muscular action of the 
rider and to transmit this work again by conveying the rider and the 
machine along the road. 
From the fact that a certain amount of the force applied in any 
machine is absorbed by the machine itself, owing to friction, etc., the 
work transmitted is always less than the work received. 
— transmitted _ ^ being the co-efficient of performance, or 
Work received 
the efficiency of the machine which is always less than unity varying 
from a low percentage, say 25 °/ Q as in some locomotives, to possibly 
98°/ c , and it maybe interesting for you as bicycle riders to know 
that I am corroborated by good authority when I say that it is 
believed that a higher efficiency is obtained from a well made bicycle 
than from any other piece of machinery that has yet been invented. 
Various forms of mechanism and chains are often stated to give 
from 20 to 40 °/ 0 extra power, that is to say assuming that from 2 to 
5 °/ Q is lost by friction the rider can get more work out of the machine 
than he puts in\\ a fact, which if correct, would not only help 
bicycles but would revolutionize the whole of the machinery in the 
world and make the fortune of the happy inventor. 
Before examining the devices employed for utilizing in the most 
efficient manner the power exerted by the pressure of the foot on the 
pedal, it is well to look very briefly at the resistances to be met with 
when riding. Opinions of experts who have carried out experiments 
seem to differ somewhat on the formulae by means of which the resis¬ 
tances can be calculated, so that I hesitate to place any before you, 
but in one or two instances I do so, more for the purpose of showing 
the influence that certain weights, dimensions, speeds, etc. have than 
for calculating the exact resistances. 
The first resistance common to all wheel vehicles, is that known 
as resistance to rolling and the formula that we shall perhaps be safe 
• p —ELn w ^ ere W = pressure normal to the road (on 
m using is > — % level roads=weight of machine + weight of rider.) 
