The 34.85-Day Cycle of Her X-1

A 5$$\frac12$$-day observation of Her X-1 is reported. At 05^h 30^m UT, 1974 April 26 we observed the turn-on from the extended low of cycle 24. The turn-on of cycle 27 did not occur during a 1$$\frac34$$-day observing period in 1974 August. It is concluded that the basic 34^d.85 cycle is not precisely predictable on the data so far available.