THE CONQUEST OF TIME AND SPACE 



evenly distributed about the circle, the more rigid the 

 pole would become. But if, on the other hand, all the 

 men were to stop pulling and slacken the ropes, the pole 

 would at once fall over. The pole, under such circum- 

 stances, would represent the axis of the revolving wheel, 

 which acquired increased stability in exact proportion 

 to the increased velocity of its revolutions, and there- 

 fore of the increased force with which its particles tend 

 to fly ofiF into space. 



But be the explanation what it may, the fact that the 

 axis of a revolving wheel acquires stability and tends to 

 maintain its fixed position in space is indisputable ; and 

 it is this fact which determines primarily the action of 

 the little revolving wheels of the gyroscopes that balance 

 Mr. Brennan's car. There are certain very important 

 additional principles involved that I shall refer to in a 

 moment, but first let us glance at the car itself and see 

 how the gyroscopes are arranged. We shall find them 

 fastened within the frame- work of the car, at its longi- 

 tudinal centre, in such a way that their axles are parallel 

 to the axles of the ordinary car-wheels when the car 

 stands in a normal position. Granted that the gyro- 

 scopes are thus transverse and normally horizontal, and 

 at right angles to the track, the exact location of the 

 mechanism within the car is immaterial. But the two 

 gyroscopes must revolve in opposite directions for a 

 reason to be given presently. 



MR. BRENNAN^S MODEL CAR 



The Brennan car as at first exhibited was only a 

 working-model about six feet in length, and the gyro- 



[ 200] 



