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outlined a method for the calculation of optimum loop gain and damping gain of a certain class of regulators. They have used a transformation which changes the characteristic equation of the system considered. The resulting equation has been such that the analysis may be applicable to all generators and to all regulators of a given class. It is pointed out in the paper that the graphical analysis is applicable to the restricted operating condition of the generator at 8 = 90°.However, making use of the generalised Mitrovic method, A -B it is possible to remove the above restrictions. The authors, in their paper, have drawn generalised Mitrovic curves for constant £, and have then tried to choose optimum values of parameters. We feel, however, that it would be better to also draw constant settling-time (col) curves and then to choose the optimum values of parameters.A set of such curves have been mapped by us c for a singlemachine system connected to an infinite busbar for three widely different operating conditions; i.e. lagging power factor, unity power factor, and leading power factor. It was observed that, for high values of 8, the operating regions corresponding to exit, and £ curves were very much restricted in contrast to the operating regions for normal 8. Therefore we feel that choosing optimum values for 8 = 90° might result in a very much underdamped system for values of 8 above 100°. We should like to know of the author's experience on this point.The authors have not included the turbine and governor in their analysis. We should like to know whether there will be any difficulty in including them. In our analysis, we included the governor and turbine and found that these parameters do affect the operating region appreciably. 27th