half past nine
At nine o'clock I had again lost sight of land to the eastward , but not before I became aware that the balloon was drifting rapidly to the N. N. W . The convexity of the ocean beneath me was very evident indeed , although my view was often interrupted by the masses of cloud which floated to and fro . I observed now that even the lightest vapors never rose to more than ten miles above the level of the sea . `` At half past nine I tried the experiment of throwing out a handful of feathers through the valve . They did not float as I had expected ; but dropped down perpendicularly , like a bullet , en masse , and with the greatest velocity -- being out of sight in a very few seconds . I did not at first know what to make of this extraordinary phenomenon ; not being able to believe that my rate of ascent had , of a sudden , met with so prodigious an acceleration . But it soon occurred to me that the atmosphere was now far too rare to sustain even the feathers ; that they actually fell , as they appeared to do , with great rapidity ; and that I had been surprised by the united velocities of their descent and my own elevation .