"Ah, Doctor, there you hit me in a tender spot. I have a sore temptation to close this switch on which my hand rests. Were I to do so, both you and Mr. Carnes would vanish forevermore. I have, however, conceived a very real affection for you two. Your brains, Doctor, working in my behalf instead of against me would render me well-nigh omnipotent. Mr. Carnes has a certain low cunning which I can also use to advantage. Both of you will join me." * * * * * "You might as well close your switch and save your breath, Saranoff, for we will do nothing of the sort," replied the doctor sharply. "Ah, but you will. So will Mr. Carnes. I had no hopes that you would join me willingly. In fact, I am pleased that you do not. I could never trust you. All the same, you will join my forces as have the others whom I have brought into the hands of the Selom. I have ways of accomplishing my desires. It pleases my fancy, Doctor, to use your brains in aiding me in my scientific developments. You will enjoy working with the scientists of the Selom. Among them you will find brains which excel any to be found on the surface of the earth, since we two are below. Already I have learned much from them. You, Mr. Carnes shall be taught to pilot an airplane. When my cohorts go forth from the realms of the Selom to establish the rule of Russia, you will be piloting one of the planes. Your first task will be to learn to fly." "I refuse to do anything of the sort!" said Carnes. "I will not be ready to have your flying lessons started until to-morrow," replied the Russian, "and you will have until then to reconsider your rash decision. It will be much easier for you if you obey my orders. If you still refuse to-morrow, you will pay a visit to the laboratory of the Selom. When you return your lessons will be started. You will now be taken to your cell. I have use for Dr. Bird this afternoon." "I won't leave Dr. Bird and that's flat!" exclaimed Carnes. Dr. Bird interrupted him. "Go ahead, Carnesy, old dear," he said lightly. "You might just as well toddle along under your own power as to be dragged along. You have a day for reflection, in any event. I daresay I'll see you again before they do anything to you." Carnes glanced keenly at the doctor's face. What he saw evidently reassured him for he turned without a word and walked away. The light grew gradually dimmer until darkness again reigned in the cavern. "Come, Doctor," said Saranoff's voice. "We have work to do." * * * * * Carnes sat alone in his cell for hours. The darkness and loneliness wore on him until he felt that his nerves would crack. Not a sound came to him. He threw himself on one of the beds and plugged his ears with his finger tips in an attempt to keep the silence out. Then a cheerful voice sounded in the cell and a friendly hand fell on his shoulder. "Well, Carnesy, old dear," said Dr. Bird, "have you been lonesome?"