[en] Balloon-borne observations of the X-ray source Her X-1 in the region 20-120 KeV during its mid-ON phase are reported. It is shown that the intensity of the source may reach a level as high as the one corresponding to the ON state. It is also shown that during the mid-ON period, the cyclotron line feature persists even in the time-averaged spectrum. The observed 35-day modulation in the intensity of Her X-1 is ascribed to increased absorption effects due either to the geometrical precession of the accretion disk around the neutron star or to increased accretion flow caused by the intrinsic stellar periodicity. 22 references