"I believe I can do it, Mr. Secretary," was Hart Jones' simple comment. "At least I will try. But you must let me have an experienced astronomer at once with whom to consult." "Astronomer?" "Yes--immediately. I have a theory, but am not enough of a student of astronomy myself to work it out." "You shall have the best man in the Air Naval Observatory at once." Secretary Simler chewed his cigar savagely. "And anything else you might need," he concluded. "There is nothing else, sir." Hart turned from the great men who regarded him solemnly, some with expressions of hope, others with plain distrust written large on their countenances. * * * * * They left in silence and we returned to our work with renewed vigor. Within an hour there arrived by fast plane an undersized, thick-spectacled man who presented himself as Professor Linquist from the government observatory. He was immediately taken into the office by Hart and the two remained behind closed doors for the best part of four hours. Meanwhile the hangar hummed with activity as usual. We in the chemical laboratory were engaged in compounding the high explosive used as fuel in the _Pioneer_. This was being compressed to its absolute limit and was stored in long steel cylinders in the form of a liquid of extremely low temperature. These cylinders were at once transferred to a special steel vault where the temperature was kept at a low enough point to prevent expansion and consequent loss of the explosive, not to speak of the danger of destroying the entire lot of us in its escape. The generating apparatus of the _Pioneer_ was to be dispensed with for this trip, since it was of no value outside the atmosphere where there was no air from which to extract the elements necessary for the production of the explosive. Instead, the entire supply of fuel for the trip was to be carried aboard the vessel in the cylinders we were engaged in filling. Hart had calculated that there was just sufficient room to store fuel for a trip of about two hundred thousand miles from the earth and a safe return. We hoped this would be enough. * * * * * On the scaffolding around the _Pioneer_ there were now so many workers that it seemed they must forever be in one another's way. But the work was progressing with extreme rapidity. Already there projected from her blunt nose a slender rod of shining metal which was the projector of one of the destructive rays whose generator and auxiliaries were being installed under the supervision of the government experts. The force had been trebled and was now working in shifts of two hours each, the pace being so exhausting that highest efficiency was obtained by using these short periods.