This was true. So well balanced was the projectile, and so delicately poised was the machinery, that the terrifically fast rate of travel, rivalling that of the earth, was no more noticed than we, on this globe, notice our pace of nineteen miles a second around the sun. "Everything seems to be all right," observed Professor Henderson, as he looked out of the plate-glass window of the pilot house into a sea of rolling mist, which represented the ether, for they had soon passed through the atmosphere of the earth, which scientists estimate to be two hundred miles in thickness. "Are we going to move any faster than this?" asked Jack, who seemed possessed of a speed mania. "Not right away," replied Mr. Henderson. "Professor Roumann wants to thoroughly test the Cardite motor first. Then, when he finds that it works all right, we may go faster. But we will be at the moon soon enough as it is. It is time we headed more directly on our proper way, though, so I think I will ask Mr. Roumann to step here and aid me in getting the projectile on the right course. You boys had better remain also and learn how it is done. You may need to know some time." "I'll call the professor here, if he can leave the engine room," said Mark, and he found the German bending over some complicated apparatus. The scientist announced that the machines would run themselves automatically for a while, so he accompanied the lad back to the pilot-house. There, consulting big charts of the heavens, and by making some intricate calculations, which the boys partly understood, the German and Mr. Henderson were able to locate the exact position of the moon, though that body was not then in sight, being behind the earth. "That ought to bring us there inside of a week," announced Mr. Henderson, as he fastened the automatic steering apparatus in place. "The projectile will now be held on a straight course, and I hope we shall not have to change it." "Could anything cause us to swerve to one side?" asked Jack. "Sure," replied Mark. "Don't you remember how, in the trip to Mars, we nearly collided with the comet? If we are in danger of hitting another one of those things, or even a meteor, we'll steer out of the way, won't we?" "Of course. I forgot about that," admitted Jack. "Yes," declared Professor Roumann, "we'll have to be on the lookout for wandering meteors or other stray heavenly bodies. But our instruments will give us timely warning of them. Now, I think we can leave the projectile to herself while I make sure that all the machinery is running smoothly. You boys may stay here if you like, though there isn't much to see."