Constance had pulled down all the shades quietly, and drew the curtains tightly between the room and the foyer.
On the top of the safe she was pouring some of the powder in a neat pile from one of the vials.
"What is that?" asked Anita, bending close to her ear.
"Some powdered metallic aluminum mixed with oxide of iron," whispered Constance in return. "I read of this thing in a scientific paper the other day, and I determined to get some of it. But I didn't think I'd ever really have occasion to use it."
She added some powder from the other vial.
"And that?"
"Magnesium powder."
Constance had lighted a match.
"Stand back, Anita," she whispered, "back, Anita," she whispered, "back in the farthest corner of the room, and keep quiet. Shut your eyes—turn your face away!"
There was a flash, blinding, then a steady, brilliant burst of noiseless, penetrating, burning flame.