162 



5 



and Y\= JS" yf Y^' 



s' 



where the cy like the yl are integral numbers. If Ys is put equal 

 to Hg . Ii, where Hs takes all positive and negative integral values, 

 the Y'l also pass through all positive and negative integral multiples 

 of h. In like manner the same set of values is obtained for the total 

 energy «^ of the system, whether expressed as a function of the Y\, 

 or of the Yl. 



3. The question arises whether the quantities Yg found above are 

 the only adiabatie invariants of these systems. 



