Abstract: A sensor for an incination measuring device which comprises a capsule (3) part-filled with a conductive liquid. First to fourth electrodes (A-D) are disposed within the capsule in contact with the liquid. An electrical signal is applied between electrodes (C, D) and one then the other of electrodes (A, B), to derive a signal indicative of the degree of immersion of the electrode (A), and then the electrode (B) within the liquid. The ratio of these signals is related to the angle of inclination of the capsule about the reference axis (O) and relative to a first reference angle defined at the gap between the electrodes (A, B). The capsule (1) is also constructed to compensate for thermal effects, by forming the sides of the capsule so that they are responsive to pressure change within the capsule caused by thermal expansion of the contents of the capsule to expand the volume of the capsule, to keep the level of liquid therein constant.