154 AN EMPIRICAL STUDY OF GYRATING BODIES. 



The specific difference between the two is that the 

 gyroscope is supported on a point at one end of the axis, 

 while the gyrostat rests on a point in or near the plane 

 of the wheel's equator. By changing the position of 

 this point the same instrument assumes the character- 

 istics of either gyroscope or gyrostat. 



Fig. 32 represents my gyrostat with its adjuncts. The 

 latter consist of two semi-circular troughs of tin, so 

 made that nearly half of the ring of the gyroscope fits 

 snugly into them — so snugly that they will not easily 

 come off. ' 



Now place the ring of the gyroscope in either of the 

 troughs. Put the ring in the vise, turning it upside 

 down so as not to injure the tin. Set the wheel in rapid 

 motion. Take the instrument out of the vise and set it 

 down on a glass plate some ten or twelve inches square. 



Instead of tilting over, it will stand with remarkable 

 steadiness. You may use it roughly — may strike with 

 sufficient force to send it across the glass — without per- 

 ceptibly disturbing its upright position. You may strike 

 on either end (at S or T) as severe a vertical blow with 

 a hammer as you dare, lest you injure the instrument, 

 and you will make but little disturbance. 



There, as in the gyroscope, the resistance is propor- 

 tioned to the force applied. A gentle, continuous push, 

 or pull, will upset it more easily than will a severe blow. 



If the wheel revolves very fast, and is nearly or quite 

 vertical, the instrument will, for a considerable time, 

 show no indication of falling. After a while, however, 

 it will be seen to be leaning over more and more, and at 



1 To make these troughs, lay the ring of the gyroscope flat on a sheet of tin, and mark an 

 almost semi-circle on each side, twice as many, of course, as you want troughs. Cut out 

 half as many straight strips somewhat wider than the thickness of the ring, and solder so as 

 to make a bottom to each trough. 



Cut out of heavy tin the pieces A and B. It will be convenient for certain purposes here- 

 after to make one strip, e. g., A, five or six inches long, with loops at two corners. Cut B of 

 the same length, and slightly curve the under side, like the diagram. Solder each to the 

 middle of a trough and at right angles to it. Across A, and about two inches apart, solder 

 two stout sharp pins. 



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