a half to seven
The sides , roof , and floor were to consist of two sheets , each one third of an inch thick and six inches apart , the space between to be filled with mineral wool , as a protection against the intense cold of space . There were also to be several keels and supports underneath , on which the car should rest . Large , toughened plate-glass windows were to be let into the roof and sides , and smaller ones in the floor , all to be furnished with thick shades and curtains . Ayrault also decided to have it divided into two stories , with ceilings six and a half to seven and a half feet high , respectively , with a sort of crow 's nest or observatory at the top ; the floors to be lattice - work , like those in the engine-room of a steamer , so that when the carpets were rolled up they should not greatly obstruct the view . The wide , flat base and the low centre of gravity would , he saw , be of use in withstanding the high winds that he knew often prevailed on Jupiter . As soon as possible he awarded the contract , and then entering his smart electric trap , steered for Vassar University along what was the old post-road -- though its builders would not have recognized it with its asphalt surface , straightened curves , and easy grades -- to ask his idol to christen the Callisto when it should be finished . Starting from the upper end of Central Park , he stopped to buy her a bunch of violets , and then ran to Poughkeepsie in two hours .