and second frames 31 35 and first second and third stages 32 33 37 the probe 29 is mounted on the first stage 32 and arranged to deflect with respect to the first stage 32 and the first frame 31 which is rigidly attached to the first stage 32 the first sensor 30 which once again may be a capacitance gauge is disposed between the probe 29 and the first frame 31 and arranged to measure the deflection of the probe 29 relative to the first frame 31 the first stage 32 is adjustably mounted on the second stage 33 the second stage 33 is supported by the second frame 35 which in turn is adjustably mounted on the third stage 37 the second sensor 34 which likewise may be a capacitance gauge is disposed between the first stage 32 and the second stage 33 and arranged to measure the displacement of the first stage 32 relative to the second stage 33 similarly the third sensor 36 which likewise may be a capacitance gauge is disposed between the second stage 33 and either the third stage 37 or the second frame 35 and arranged to measure the displacement of the second stage 33 relative to the third stage 37 or the second frame 35 respectively in use the profile of the surface 11 of the workpiece 9 is measured using the.