Captain Somers cut the engine switch. The engines continued firing, pressing the men deeper into their couches. The cabin lights flickered, went out, came on again.

And still the acceleration mounted and Dierdre's engines howled in agony, thrusting the ship forward. Somers raised one leaden hand and inched it toward the emergency cut-off switch. With a fantastic expenditure of energy, he reached the switch, depressed it.

The engines stopped with dramatic suddenness, while tortured metal creaked and groaned. The lights flickered rapidly, as though Dierdre were blinking in pain. They steadied and then there was silence.

Watkins hurried to the engine room. He returned morosely.

"Of all the damn things," he muttered.

"What was it?" Captain Somers asked.

"Main firing circuit. It fused on us." He shook his head. "Metal fatigue, I'd say. It must have been flawed for years."

"When was it last checked out?"

"Well, it's a sealed unit. Supposed to outlast the ship. Absolutely foolproof, unless—"

"Unless it's flawed."