161 



FIG. 4-. The wanaton of a small second harmonic perturbation 

 of the shape of the txjbtdc during two pulsotions • 



-4 



b9-Oatt-2T' 



--(•5 



FIG • S • Tne variation of the ncn- sphericity /8/w as a 

 function of t oscr two pulsations - 



