They had come down in a fog--which was not surprising, since fogs now hovered continually over the earth; and their exact point of descent was an isolated spot in a city park, a mile or two from the laboratory. Dunbar recognized the place with a satisfied grunt, as he identified a certain rustic bridge over a small stream. "Good! Just ideal for a little chat!" It seemed as if a huge shadow drifted over them and away, and vaguely they were aware that the two Saturnians had departed. "What is there to chat about, Mr. Dunbar?" she flung back haughtily. There was a silken purr in the man's voice. But determination marked his manner as he imposed himself in the girl's path. "Now listen here, young lady. There are several things you might as well understand. The first is that you must co-operate." "Co-operate?" she tossed back, shrilly, and paused long enough for a contemptuous fling of laughter. "Why, who wouldn't die sooner than co-operate with those beasts--those dev--" He had come closer to her, and his voice was coaxing, almost caressing. "Do you think it was for their sake, Eleanor? Why do you think I saved you, except for your own precious self? If you will only co-operate with me--with _me_--" "I'd rather co-operate with a viper!" She had recoiled as though he were indeed the creature she had mentioned; and he found it necessary to seize her arm in order to prevent her departure. "Come, let's forget all this, Eleanor. I know what nervous stress you are under. When you return to yourself, you will realize all that I have done for you. If I hadn't said a word in your behalf--" "In _my_ behalf! Good heavens, man!" she retorted, bitterly. "Don't you think I could have saved my own life, if I had been willing to stoop to your kind of treason?" "Treason or not, we shall see. We shall see. Meanwhile, I warn you, don't try to interfere when I fulfill my agreement--when I prepare those vats of compressed air--" "And what if I report you to the authorities?" "Report? By Christ! You wouldn't be that stupid? You wouldn't drive me to action against you, would you?" His tone had become subtly menacing as he leaned over her, and whispered, almost furtively, "Besides, have you not as much at stake as I, my girl? Remember, you are a pledge for my success. If I fail--" "If you fail, I will give thanks to heaven!" With a determined effort, she had thrust herself forward; while he, following through the fog, pleaded and expostulated, in tones half like a lover, half like a taskmaster. At length, through the mist, there came a choked sobbing. And thin and faint, where two enormous creatures stood invisibly amid the vapors, there sounded an eerie squeak, like the muffled mockery of demons. * * * * *