THE CONQUEST OF TIME AND SPACE 



In this new position of balance, the car (owing to a 

 shift of its load or to the force of the wind) may be tipped 

 far over to one side, as a man leans in carrying a weight 

 on one shoulder, to get the centre of gravity over the rail, 

 and in that event the axis of the gyroscope will be no 

 longer horizontal. But that is quite immaterial. There 

 is no more merit in the horizontal position than in any 

 other, as regards the tendency to keep a fixed axis. If 

 it is usually horizontal, this is only because under nor- 

 mal conditions the car will be balanced at its physical 

 centre, just as ordinarily a man stands erect and does not 

 lean to one side in walking. 



Reverting for a moment to our diagram and the ex- 

 planation just given, it will be understood that the two 

 rollers Ri and R2 are never in action at the same time, 

 and that it is only the roller Ri that gives the side wise 

 push that accelerates the precession (since R2 is not in 

 contact with the axle itself). 



The function of R2 is to retard the precession and 

 bring the axis to its normal position at right angles to 

 the rail on which the car runs. There is nothing of 

 mystery about the action of either which the action of 

 our gyrostat does not explain, but the mechanism by 

 which the different segments of the car are made to push 

 against the spindle, and so force it to balance the car in 

 order that it may maintain its own balance, is exceed- 

 ingly ingenious. Mr. Brennan himself tells me that 

 he has improved methods of accomplishing these results, 

 which are not yet to be made public. The principle, 

 however, is the same as that outlined in the earlier 

 patents which I have just described. 



[210] 



