C. B. WARRING. 71 



Some attribute the two effects largely to friction, but 

 this explanation is disproved by the simple fact that the 

 less the friction the better the instrument works. A 

 writer in ApjpletorC s Encylopedia says that gravity acts 

 with the motion of the disk on one side and against it 

 on the other; i. e., the side which is going downward is 

 accelerated by gravity, while the other side, moving up- 

 ward, is retarded. Thus, there is a greater force on one 

 side than on the other, and of course the Gyroscope is 

 pushed around by the greater force. This is sufficiently 

 disproved by placing the instrument so that it is free to 

 move around its support horizontally, but not to fall any. 

 It is found on trial that no matter how fast or how slow 

 the disk revolves on its axis, there is no horizontal mo- 

 tion whatever. Without going any further in the expla- 

 nations which have been offered, it is enough to say that 

 the problems involved have been regarded as offering 

 very considerable difficulty, and in all school works are 

 passed over without any real solution. 



The two questions which have been mentioned I shall 

 endeavor to answer. 



First. Why, in apparent defiance of the law of gravita- 

 tion does the Gyroscope, when supported only at one 

 end, remain in a horizontal position? 



Before attempting an explanation, I ask that the fol- 

 lowing self-evident principles be admitted : 



A body set in motion will continue in motion until 

 something stops it. This is a part of Newton's first law 

 of motion. Its best illustration for the present purpose 

 is afforded by the pendulum. When the latter reaches 

 the bottom of its arc it does not stop, but continues on 

 its course up the opposite arc until the continued action 

 of gravitation has produced a counter-force just equal to 

 that caused by the fall, and then it stops. Again 

 gravity draws it down, and again it rises. And so it 

 goes on. Except for outside resistance — that from the 



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