Steel coming out of an electric furnace is first poured into ingots, after which the ingots are taken to the forge shop to be shaped on the forge. Before going to the forge, the ingots must be preheated to bring them up to a temperature that is suitable for forging. The time that an ingot must spend in preheat depends on its temperature when it is placed in the furnace. If ingots are brought to the forge shop immediately after being poured, the preheat time will be low. However, if for some reason they are allowed to stand and cool after being poured, the preheat time will be greater. The preheat ovens in a steel mill's forge shop are currently being used at about full capacity, and the foreman is studying the question of how much capacity could be increased if ingots were always brought to the forge shop promptly after being poured. To answer this question he must know how the preheat time needed changes with the temperature of the ingots. This time will depend somewhat on other factors, such as precisely how the furnace is loaded, but it will mainly be a function of the temperature of the