408 
THE MECHANISM OF BICYCLES. 
Fig . 2, 
represent the maximum thrust I could produce when moving very slowly, when 
moving at speed they would be considerably modified. 
Major von Donop : The dotted line represents the position of the saddle; 
it points towards the saddle. 
The Chairman : Will any other Member offer any remarks? I see a recent 
addition to the ranks of bicyclists here in the person of Professor Greenhill. 
Professor A. G. Greenhill, E.B.S.: It is for that reason, Sir, that I feel 1 
am not qualified to take any part in this discussion, having only just begun on 
the machine. Perhaps, however, my impressions of the evolutions are more vivid 
and more valuable than they would be at a future day when I am more accustom¬ 
ed to the motion. 
The “ Dynamics of the Bicycle ” has been proposed as the subject of a Prize 
Essay by the Paris Academy of Sciences. In its generality the motion is hyper- 
elliptic, tending gradually to an elliptic solution, in its penultimate stage of 
steadiness ; and with perfect skill all trace of elliptical transcendentalism disap¬ 
pears. I assume that the riders will have reached the elliptic stage before they 
are permitted to venture out upon the road ; for myself I have not yet emerged 
from the hyper-elliptic stage. 
