A Murphy cup removes the need for temperature calculations. The dial is a thermometer, with the temperature face removed and replaced with the appropriate hydrometer readings for each temperature. It does not remove the need for hydrometer, only the temperature calculations. A is still required. As with any regular hydrometer cup, fill it with syrup and float the hydrometer. If the dial on the cup matches the reading on the hydrometer, syrup has been achieved. 

A user's guide will be included.