CHAPTER VI. INSTRUCTIVE CONVERSATION. On the fourth of December, the Projectile chronometers marked five o'clock in the morning, just as the travellers woke up from a pleasant slumber. They had now been 54 hours on their journey. As to lapse of time, they had passed not much more than half of the number of hours during which their trip was to last; but, as to lapse of space, they had already accomplished very nearly the seven-tenths of their passage. This difference between time and distance was due to the regular retardation of their velocity. They looked at the earth through