Two weeks were devoted to final preparations for the remarkable adventure. A powerful, adjustable searchlight had now been installed within a socket in the bottom of the _Sphere_ to facilitate night travel and landings in the future. Petrol tanks were filled to capacity, and a supply of water taken on, some of which would be used in the cooling coils of the engines. A liberal quantity of life-giving oxygen was forced into the high-pressure tanks. Without this to constantly freshen the air within the _Sphere_, they could not live, as, after passing beyond the Earth’s envelope of atmosphere into the void of space, they would have no means of replenishing their air supply. A small supply of nitrogen was also added as a precaution against the total loss of the little ball of atmosphere guarded by the walls of the _Sphere_. While oxygen had to be replenished as their respiration consumed it, the supply of nitrogen would remain virtually the same except for a slight seepage through the sealed walls when the protecting pressure of the Earth’s atmosphere was removed. The atmospheric pressure within the _Sphere_ would be about fifteen pounds to the square inch, with the absolute vacuum of space hungrily enveloping the exterior. An apparatus for absorbing the carbonic acid gas thrown off by their lungs was also a part of the _Sphere’s_ equipment. Robert tinkered about the _Sphere_, constantly inspecting every part with painstaking care. The resilient rubber window strips, insuring against the loss of the precious atmosphere, were looked to with especial care. The heavy glass panes were examined minutely for possible signs of fracture, or flaws. Such a defect would prove disastrous if it should give way under the pressure within when they were in space. They would then be placed in a vacuum in which no living body can exist. So sudden would such a disaster be that they would have no opportunity, nor means, of saving themselves. All windows, however, were equipped with double panes for safety as well as warmth. They were also fitted outside with guards of heavy wire net. The lubricating reservoirs of the gyrostats were filled carefully; the bearings were cleaned perfectly. Engines were tuned, and, in short, every bit of mechanism was tested and regulated to a point of perfection. On the first day of August everything was in readiness for the start of the momentous journey. Provisions, chiefly of the non-perishable and concentrated variety, had been generously stored in the _Sphere’s_ food chests. There was a sufficient quantity to last them for months. Although the world at large understood that the _Sphere_ would start on its trip about this time, Robert and the professor had decided to withhold information as to the exact day or hour of their departure. Neither one desired a public demonstration. In spite of the pleas of divers reporters who besieged them, they refused to divulge the time set for their departure.