"Well, I'm going up after the generators of this mysterious force that is destroying our cross-country ships and killing our people," asserted Hart. "The rays came from high above, but the _Pioneer_ can go as high as anything that ever flew--_higher_." He snapped a switch and a beam of light that rivalled the so-called pillar of fire bored far into the night, dimming the stars by its brilliance. Again his fingers strayed to the rows of white keys and the rocket tubes shrieked in response to his pressure. This time I was prepared for the shock of acceleration, but the action was maintained for several seconds and I found the pressure against my back growing painful. Then it was relieved, and I glanced at the altimeter. Its needle had reached the end of the scale, which was graduated to eighty thousand feet! "Good Lord!" I exclaimed. "Do you mean to tell me that we are more than sixteen miles in the air?" "Nearly thirty," replied Hart, pointing to another dial which I had not seen. This one was graduated in miles above sea-level, and its needle wavered between the twenty-nine and thirty mark! * * * * * Again Hart pressed the rocket buttons, and we shot still higher into the heavens. Thirty, forty, fifty miles registered the meter, and still we climbed. "Great Scott!" blurted a voice I knew was my own, though I had no consciousness of willing the speech. "At this rate we'll reach the moon!" "We could, if we wished," was Hart's astounding reply; "I wish you wouldn't say too much about it when we return. We have oxygen to breathe and an air-tight vessel to retain it. With the fuel we are using, we could easily do it, provided a sufficient supply were available. However, the _Pioneer_ does not have large enough storage tanks as yet, and, of course, we cannot now replenish our supply with sufficient rapidity, for the atmosphere has become very rare indeed--where we are. My ultimate object, though, in building the _Pioneer_, was to construct a vessel that is capable of a trip to the moon." "You think you could reach a great enough velocity to escape the gravitational pull of the earth?" I asked, marveling more and more at the temerity and resourcefulness of my science-minded friend. "Absolutely," he replied. "The speed required is less than seven miles a second, and I have calculated that the _Pioneer_ can do no less than twenty." Mentally I multiplied by sixty. I could hardly credit the result. Twelve hundred miles a minute! "But, how about the acceleration?" I ventured. "Could the human body stand up under the strain?" "That is the one problem remaining," he replied; "and I am now working on a method of neutralizing it. From the latest results of our experiments, George and I are certain of its feasibility." * * * * *