At another furnace, an opened door, where the heat poured out in a constricting blast, workmen were shovelling in powdery white stone; moving up with their heads averted, and quickly retreating with shielding arms.  “That’s dolomite,” James Polder’s explanations went rapidly forward.  “They are banking up the furnace.  The other, in the bins, is ferro manganese.”  He procured a pair of spectacles; and, with a protected gaze, Howat looked into a furnace, an appalling space of apparently bubbling milk over which played sheets of ignited gases.  The skin on his forehead shrivelled like scorching paper.

“I particularly wanted you to see a heat tapped,” Polder told Mariana.  “And they’re making a test at number four.”  They followed him to where a small ladle of metal had been dipped out of a furnace.  It was poured, with a red-gold shower of sparks, into a mould, then dropped in a trough of water.  The miniature ingot, broken under the wide sweep of a sledge, was examined by a lean, grizzled workman—­“the melter”—­who nodded.  “We must get back of the furnace,” Polder continued, indicating a narrow opening between brick walls through the unstopped chinks of which seethed the scorifying blaze.

Howat Penny stood at a railing, looking down into an apparent confusion of slag and cars, pits and gigantic ladles and upright moulds set upon circular bases.  A crane rumbled forward, grappled a hundred-ton ladle, a fabulous iron pot, and petulantly deposited it under a channel extending out from the base of the furnace where they had been stationed.  A workman steadied himself below their level and picked with a long iron bar at a plugged opening.  It was, James Polder went on, the most dangerous moment of the process—­“sometimes the furnace blows out.”  The labour of tapping was prolonged until Howat was conscious of an oppressive tension.  Workmen had gathered, waiting, in the pit.  More appeared along the railing above.  This was, he felt, the supreme, the dramatic, height of steel making.  The men suddenly seemed puny, insignificant, before the stupendous, volcanic energy they had evoked.  The tapping stopped.  Polder commenced, “It will be rammed out from the front—­”

A stunning white flare filled the far roof with a dazzling illumination; and, in a dull explosion, a terrific billowing of heat, a cataract of liquid steel burst out through lambent orange and blue flames.  It poured, searing the vision, into the ladle, over which rosy clouds accumulated in a bank drifting through the great space of the shed.  Nothing, Howat thought, could contain, control, the appalling expansion, the furious volume, of seething white metal.  He was obliged to turn away, blinded by sheets of complementary green hanging before his eyes.