Abstract: In the controlled application of fluid polishes to polishing wheels (16) a controlled nozzle head is used which has a polish chamber (12), a nozzle (14) and a valve body (10), the polish being fed to the polish chamber (12) from an external supply tank (2). In order to reduce the apparatus cost, the wasting of polish and the contamination of the surrounding area by fast adaptation of the metering properties, the polish is fed to the nozzle head (1) by means of an external high-pressure pump (21). The nozzle head (1) is moved transversely across at least one polishing wheel (16), and the valve body (10) is controlled, regardless of the supply pressure of the high-pressure pump (21), by at least one external control dependent upon the movement of the nozzle head (1). In a metering apparatus especially appropriate for this use the valve body (10) is controlled by signals which issue from cams which are arranged parallel to the line of movement of the nozzle head.