Abstract :
The author of the above-named work, which appeared on pp. 727-741 of the July, 1966, issue of these Transactions, has requested that several corrections be made: In the lower right-hand part of Fig. 1, Gri should be Gr1. The equations in the caption of Fig. 2 are corrected herein, and the caption of Fig. 3 should read, "The 2-area system with elastic tie line"; and Fig. 4, "A 2-area and an n-area stiff tie-line system."