"I am not a chemist. I don't know." The idea of chemistry was slightly unfamiliar to them; it was apparent from their thoughts that chemistry had never occurred to them as the subject of a special study. Then came another question, "Are there many chemists?"
An idea struck Sherman. He closed his mind resolutely against the question and flashed back the message that he had come to learn as well as teach. He sensed a certain annoyance among the new auditors, but the old Lassan answered, "That is only just. What do you wish to know?"
"What the machines are for."
"In the center of this as of every other earth lies the substance of life, as it lies at the heart of every sun. The machines pierce to it and draw it up for our uses."
"What is this substance of life?"
"You would not understand if we told you. Sufficient that it is nothing known on the surface of your world. Your idea that most nearly approaches it is—" he paused for a moment, feeling about in Sherman's mind for the proper expression "—is pure light; light having material body and strength. Now let me ask—do you use explosives as we use the substance of life, to fight your enemies?"
"Yes."
"What weapons do you use them in?"
Sherman thought of a revolver and then of a cannon.
"And do these weapons act at a distance?"