In the one batch of methylmethacrylate tested the surface of the setting cement never exceeded 70 degrees centigrade while the setting time was prolonged by lowering the ambient temperature, decreasing the powder to liquid ratio, and increasing the mass of cement. Working time, that is, the interval between the dough stage and setting, did not change as the powder-liquid ratio varied but decreased with rises in ambient temperature and mass. Batch to batch variation should be expected, and even greater variation will occur with minor variations in composition of cement.