He paused, frowning hard; then vetoed his own plan. "Thunder; I'm always speaking first and thinking afterward. I never used to do it," accusingly, "until I got in with you folks. Anyhow, electricity won't do; you've got to have practically pure elements for that, too."

"Guess it's up to you, doc," said Billie. And they all looked respectfully toward their host.

He laughed. "You three will never learn anything. You'll continue to think that I'm a regular wonder about these things, but you never notice that I merely stay still and let you commit yourselves first before I say anything. All I have to do is select the one idea remaining after you've disproved the rest. Nothing to it!"

He paused. "I'm afraid we're reduced to the spark method. It would take too long to procure materials pure enough for any other plan. Friction is out of the question for such people; they haven't the patience. Suppose we go ahead on the flint-and-spark basis."

They went at once into the familiar trance state. Nightfall was approaching on the part of Sanus in which they were interested. Smith and Van Emmon came upon Dulnop and Corrus as they were talking together. The herdsman was saying:

"Lad, my heart is heavy this night." Much of his usual vigor was absent. "When I were passing Cunora's field this day, some of the masters came and drove me over to her side. I tried to get away, and one threatened to kill. I fear me, lad, they intend to force us to marry!"

"What!" fiercely, from the younger.

Corrus laid a hand upon his arm. "Nay, Dulnop; fear not. I have no feeling for thy Cunora; I may marry her, but as for fathering her children—no!"

"Suppose," through set teeth, "suppose They should threaten to kill thee?"

"I should rather die, Dulnop, than be untrue to Rolla!"