In the great iron foundries in making Bessemer steel, the process of purification is watched through a spectroscope, in which the changing colors of the flames show exactly when the metal is perfectly ready for its uses. When the flame becomes a certain precise shade of color then the great crucible is tilted and the metal poured into molds. So the great Divine Refiner, the loving Christ sits down by the crucible of our discipline and chastening, watches intently to see when the fire has done its work; and when this is reached, the metal is removed from the flames. Not a pang, a pain, or a sorrow that is not necessary to our purifying will He permit.