t?" I asked. "It is just the opposite of a fish's tail. You have the
widened end near the projectile and the narrow end extending."

"Yes, and with good reason. You will note that the rudder slides into
the rear end of the projectile so that none of it extends out. This is a
variable steering apparatus, adapted to every sort of atmosphere.
Naturally, a rudder that would steer in the water, might not steer the
same craft in the air. There is probably a vaster difference between air
and ether than between water and air. It is necessary, therefore, to
have a small rudder with but little extending surface in thick
atmosphere; but when it becomes thinner the rudder must be pushed out,
so that a greater surface will offer resistance. When we start, the
smallest portion of this rudder moved but the sixteenth of an inch, up,
down, or to either side, will quickly change our course correspondingly.
When we have reached the ether, the full surface of the rudder pushed
out and exposed broadside may not have much effect in changing our
course. This is one of the things that we cannot possibly know till we
try. However, if ether is anything at all but a name, if it is the
thinnest, lightest conceivable gas, and we are rushing through it at a
speed of a thousand miles a minute, our rudder certainly should have
some effect."

"But suppose you cannot steer at all in the ether, what then?" I
interposed, hunting all the trouble possible.

"Even that will not be so very dreadful, provided we have taken a true
course for Mars while coming through the Earth's atmosphere. There is no
other planet or star nearer to us than Mars when in opposition.
Therefore there will be nothing to attract us out of our correct course;
and if we can manage to come anywhere near the true course, the
gravitational attraction of Mars will draw us to him in a straight line.
The Moon might give us some trouble, and we shall be obliged, either to
avoid her entirely by starting so as to cross her orbit when she is on
the opposite side of the Earth, or else go directly to the Moon, land
there, and make a new start. But if the ether which surrounds the Moon
(for she has no atmosphere so far as we know) has no resisting power
whatever, we might have rather a difficult time there. The only thing we
could do would be to land on the side toward the Earth, then disembark
and carry the projectile on our shoulders around the Moon to the
opposite side, making a new start fro