CHARLES B. WARRING. 159 
enough to keep from falling on our faces. As to fall- 
ing sideways, that is prevented exactly as when both 
wheels are used, the ’cyclist turns the cross-bar to right 
or left. Experience, a level head, and a steady hand tell 
him how far to turn it. 
From what has been shown, we may conclude that 
the danger of a header increases as the height of the 
saddle grows greater ; and decreases as the saddle is put 
further back. 
The danger of tilting over sidewise grows less as the 
height of the saddle is increased. 
But besides this, another element of the problem comes 
into action. I refer to the relative ease of managing the 
different kinds of ’cycles. 
Ability to keep from falling to either side, depends 
upon the rider’s ability to keep B (the front wheel) Fig. 
6, or 7, in the vertical plane passing through C and A, 
or, in other words, to make B move promptly to right or 
left as the machine happens to lean. If A were directly 
over B, then if A leaned three inches it would be neces- 
sary to move B only three inches. If A be moved back 
until it is half way between Cand B, (C, so far as lateral 
movement is concerned, is always at rest) then to bring B 
into the vertical plane passing through Cand A, it must 
be moved six inches to the leaning side. If from C to 
B is four feet, and A is only one foot forward of C, 
then B must move twelve inches to correct the same in- 
clination as before. If A is moved back until it is just 
over C, then the number of inches necessary to bring B into 
the vertical plane, would be infinite, which is only the 
mathematical way of saying that it would then be im- 
possible by moving B, to keep the machine from falling 
over. 
Calling the distance C P, a, and P B, 6, we have the 
a 
lateral stability = Gale If we let 6 be a constant quan- 
109 
