1884.] on Bicycles and Tricycles in Theory and in Practice. 15 



health. About a year ago there appeared in the Lancet an article 

 condemning in no measured terms the evils likely to result from the 

 development of this new craze, in which, as far as I remember, it was 

 stated that we are now sowing the seeds of a series of new diseases, 

 the symptoms of which will only appear possibly in years to come. I 

 would not for a moment question the accuracy of opinion held by any 

 professional man : whether this is or is not the case I cannot tell ; 

 however, I may mention that the only symptoms which I have so far 

 discovered in myself are an improved appetite, increased weight, and 

 a general robustness to which I was formerly a perfect stranger. 



Having, I trust, succeeded in showing that the advantages offered 

 to riders are sufficient to account for the rapid development of cycling — 

 that it is, in fact, no mere temporary craze — I shall now proceed to 

 consider the theory and construction of the various machines at 

 present known. 



From the hobby-horse to the bone-shaker, and from the bone- 

 shaker to the bicycle, the steps are so simple and obvious that it is 

 quite unnecessary for me to trace them. It is also needless for me to 

 describe the modern bicycle : every one must be familiar with it, every 

 one must have seen the ridiculous zig-zag of the beginner, and have 

 admired the graceful gliding of an accomplished rider. Of the theory 

 of the balance little need be said ; anything supported on a mere line, 

 in unstable equilibrium, as it is called, must fall one way or the other. 

 The machine and rider would of necessity capsize if some action of 

 recovery were not possible. To whichever side the machine shows 

 any inclination, to that side the rider instinctively directs it ; by this 

 means the tendency to fall to one side is balanced by the property of 

 the rider to continue moving in a straight line and so to go over on 

 the other side. This action of recovery is always overdone, so that a 

 second turn in the opposite direction must follow. Hence the extra- 

 ordinary path traced by the beginner. Even with the most skilful 

 rider, though he appears to travel in a perfectly straight line, a 

 slightly sinuous course is essential, as the highly characteristic track 

 left on the road indicates. If anything should happen to check this 

 slightly serpentine motion — as, for instance, occurs when the driving- 

 wheel drops in the groove of a tram line — the balance at once becomes 

 impossible, and the rider is compelled to dismount. 



The extraordinary stability of the bicycle at a high speed depends 

 largely on the gyroscopic action of the wheels. On the table is a top 

 supported in a ring which is free to move how it pleases. So long 

 as the top is spinning the ring is as rigid as a block ; on stopping it 

 the freedom of the support is at once apparent. 



It is a marvel to many how anything so light, how anything so 

 delicate, can carry the weight, or can travel at the speed so common, 

 without utterly collapsing. The wheels especially attract attention. 

 In a hoop no one part can be pushed in unless some other part can 

 go out. A bicycle wheel is a hoop in which every part is jDrevented 

 from going out by the tension of the spokes. To give the wheel 



