An hour passed. And now, under the circle of light cast by the hooded lamp upon the table, there in that bare, wrecked office-home of theirs, the Pulverite was coming to its birth.
Already at the bottom of the metal dish lay a thin yellow cloud, something that looked like London fog on a December morning. There, covered with the water, it gently swirled and curdled, with strange metallic glints and oily sheens, as Beatrice with a gold spoon stirred it at the engineer's command.
From moment to moment he dropped in a minute quantity of glycerin, out of a glass test-tube, graduated to the hundredth of an ounce. Keenly, under the lamp-shine, he watched the final reaction; his face, very pale and set, reflected a little of the mental stress that bound him.
Along the table-edge before him, limp in its sling, his wounded arm lay useless. Yet with his left hand he controlled the sleeping giant in the dish. And as he dropped the glycerin, he counted.
"Ten, eleven, twelve--fifteen, sixteen--twenty! Now! Now pour the water off, quick! Quick!"
Splendidly the girl obeyed. The water ran, foaming strangely, out into a glass jar set to receive it. Her hands trembled not, nor did she hesitate. Only, a line formed between her brows; and her breath, half-held, came quickly through her lips.
"Stop!"
His voice rang like a shot.
"Now, decant it through this funnel, into the vials!"
Again, using both hands for steadiness, she did his bidding.
And one by one as she filled the little flasks of chained death, the engineer stoppered them with his left hand.
When the last was done, Stern drew a tremendous sigh, and dashed the sweat from his forehead with a gesture of victory.
Into the residue in the dish he poured a little nitric acid.
"That's got no kick left in it, now, anyhow," said he relieved. "The HNO3 tames it, quick enough. But the bottles--take care--don't tip one over, as you love your life!"
He stood up, slowly, and for a moment remained there, his face in the shadow of the lamp-shade, holding to the table-edge for support, with his left hand.
At him the girl looked.
"And now," she began, "now--?"
The question had no time for completion. For even as she spoke, a swift little something flicked through the window, behind them.
It struck the opposite wall with a sharp crack! then fell slithering to the floor.
Outside, against the building, they heard another and another little shock; and all at once a second missile darted through the air.
This hit the lamp. Stern grabbed the shade and steadied it. Beatrice stooped and snatched up the thing from where it lay beside the table.