Astounding Stories of Super-Science February 1930. Various

      An orderly rushed Thurston to the telephone. "You are wanted at once; Los Angeles calling."

      The voice of MacGregor was cool and unhurried as Thurston listened. "Grab a plane, old man," he was saying, "and come up here on the jump."

      The phrase brought a grim smile to Thurston's tired lips. "Hell's popping!" the Secretary of War had added on that evening those long ages before. Did MacGregor have something? Was a different kind of hell preparing to pop? The thoughts flashed through the listener's mind.