MAGNETIC ATTRACTION. 



action, compressing the spring in the middle. 

 The tendencies to expansion of the governor 

 balls and the central spring balance each other, 

 in the position shown, for a certain speed of 

 revolution. At E,F are connections for uni- 

 versal joints, without holes or pins, which 

 enable the revolutions of the particles to con- 

 trol and be controlled by one another, but do 

 not enable the particles to pull one another, 

 though they may push. 



When the ring of particles is in equilibrium 

 (imagine them kept in their places by a groove 

 or tube, inside which they revolve without 

 friction), let A undergo some special vibrations 

 by means of which it can quicken the revolu- 

 tions of the particles of the medium in front of 

 it towards B, while retarding the revolutions of 

 those behind it all the way round the rest of 

 the ring. 



The quickened revolutions through A G B 

 increase the centrifugal force of the masses 

 C, D, and cause the particles to flatten out 

 vertically, while they contract horizontally, 

 the spring being compressed, so that E and F 

 are nearer together, and the particles do not 

 push one another so hard. 



As the particles in the rest of the ring are 

 revolving more slowly, the C and D masses 

 have less centrifugal force, and allow the 

 springs to expand, causing the particles to 

 press against one another more forcibly. 

 N 193 



