"No!" cried Ardan in surprise. "Bless us! How rapidly the time passes when we are engaged in scientific conversation! Ouf! I'm getting decidedly too learned! I feel as if I had swallowed a library!" "I feel," observed M'Nicholl, "as if I had been listening to a lecture on Astronomy in the _Star_ course." "Better stir around a little more," said the Frenchman; "fatigue of body is the best antidote to such severe mental labor as ours. I'll run up the ladder a bit." So saying, he paid another visit to the upper portion of the Projectile and remained there awhile whistling _Malbrouk_, whilst his companions amused themselves in looking through the floor window. Ardan was coming down the ladder, when his whistling was cut short by a sudden exclamation of surprise. "What's the matter?" asked Barbican quickly, as he looked up and saw the Frenchman pointing to something outside the Projectile. Approaching the window, Barbican saw with much surprise a sort of flattened bag floating in space and only a few yards off. It seemed perfectly motionless, and, consequently, the travellers knew that it must be animated by the same ascensional movement as themselves. "What on earth can such a consarn be, Barbican?" asked Ardan, who every now and then liked to ventilate his stock of American slang. "Is it one of those particles of meteoric matter you were speaking of just now, caught within the sphere of our Projectile's attraction and accompanying us to the Moon?" "What I am surprised at," observed the Captain, "is that though the specific gravity of that body is far inferior to that of our Projectile, it moves with exactly the same velocity." "Captain," said Barbican, after a moment's reflection, "I know no more what that object is than you do, but I can understand very well why it keeps abreast with the Projectile." "Very well then, why?" "Because, my dear Captain, we are moving through a vacuum, and because all bodies fall or move--the same thing--with equal velocity through a vacuum, no matter what may be their shape or their specific gravity. It is the air alone that makes a difference of weight. Produce an artificial vacuum in a glass tube and you will see that all objects whatever falling through, whether bits of feather or grains of shot, move with precisely the same rapidity. Up here, in space, like cause and like effect." "Correct," assented M'Nicholl. "Everything therefore that we shall throw out of the Projectile is bound to accompany us to the Moon." "Well, we _were_ smart!" cried Ardan suddenly. "How so, friend Michael?" asked Barbican.