A monitoring apparatus is provided to monitor an amount of a liquid discharged from a nozzle. These wave plates can be used to compensate for the phase retardations existing in various modes of LCDs including TN, VA, IPS, and OCB, and therefore improving the viewing quality of the displays. Current flow is selectively removed from the plurality of induction coils, and a cooling medium surrounding the vessel, such as water flowing through hollow induction coils, solidifies the molten metal into a highly purified crystalline solid. The communication schema further comprises a lead message having lead information, lead status, and dealer action information. After the calibration image pair is made, the fiducial structure is removed. The lever eccentrically rotates so as to urge a cam and cam teeth to engage the teeth of a ratchet wheel, thereby selecting an appropriate unidirectional path.