Since a thermally induced helical inversion has been observed in cholesteryl 2-(2 ethoxyethoxy) ethyl carbonate (CEC), it has been the view that compensation of the helical structure of cholesteric liquid crystals does not require the presence of two compounds which separately form a right and a left handed helix. The present investigation demonstrates that the material used in the previous investigation was probably a compensated mixture because it contained an impurity in a rather high concentration. Pure CEC forms a right handed helix with a pitch of 6000 Å at room temperature, and with no indication of a thermally induced helical inversion. It is further shown that in general the sense of the helical screw is not necessarily identical with the sign of the optical rotation of the constituent molecules.