"But then," replied the major, "you will have to give this
projectile enormous dimensions."

"No! Be so good as to listen. You know that optical
instruments have acquired great perfection; with certain
instruments we have succeeded in obtaining enlargements of 6,000
times and reducing the moon to within forty miles' distance.
Now, at this distance, any objects sixty feet square would be
perfectly visible.

"If, then, the penetrative power of telescopes has not been
further increased, it is because that power detracts from their
light; and the moon, which is but a reflecting mirror, does not
give back sufficient light to enable us to perceive objects of
lesser magnitude."

"Well, then, what do you propose to do?" asked the general.
"Would you give your projectile a diameter of sixty feet?"

"Not so."

"Do you intend, then, to increase the luminous power of the moon?"

"Exactly so. If I can succeed in diminishing the density of the
atmosphere through which the moon's light has to travel I shall
have rendered her light more intense. To effect that object it
will be enough to establish a telescope on some elevated mountain.
That is what we will do."