Abstract: A vertically elongated glassmaking furnace is provided with two groups of electrodes: one group comprises crossed pairs of electrodes positioned in the upper portion of the furnace and is operated to melt glass batch and to establish an upward flow of hot glass along the center of the furnace; a second group is positioned in the lower portion of the furnace and operated to slow the downward flow of molten glass through the furnace, particularly near the walls of the furnace so that all the molten glass in the lower portion of the furnace flows uniformly downwardly to discharge at a rate sufficiently slow to insure the upward escape of seeds or bubbles from the discharged glass. The crossed. pairs of electrodes are energized in such a way as to provide intersecting lines of current flow with the loci of intersection in the vicinity of the central vertical axis of the furnace.