ffect they got.

Morey divided his time between piloting the ship while Arcot rested, and
observing the system. By the end of the third day, he had made very
creditable progress with his map.

He had located only six planets, but he was certain there were others.
For the sake of simplicity, he had assumed circular orbits and
calculated their approximate orbital velocities from their distance from
the sun. He had determined the mass of the sun from direct weighings
aboard their ship. He soon had a fair diagram of the system constructed
mathematically, and experimental observation showed it to be a very
close approximation.

The planets were rather more massive than those of Sol. The innermost
planet had a third again the diameter of Mercury and was four million
miles farther from the primary. He named it Hermes. The next one, which
he named Aphrodite, the Greek goddess corresponding to the Roman Venus,
was only a little larger than Venus and was some eight million miles
farther from its primary--seventy-five million miles from the central
sun.

The next, which Morey called Terra, was very much like Earth. At a
distance of a hundred and twenty-four million miles from the sun, it
must have received almost the same amount of heat that Earth does, for
this sun was considerably brighter than Sol.

Terra was eight thousand two hundred miles in diameter, with a fairly
clear atmosphere and a varying albedo which indicated clouds in the
atmosphere. Morey had every reason to believe that it might be
inhabited, but he had no proof because his photographs were consistently
poor due to the glare of the sun.

The rest of the planets proved to be of little interest. In the place
where, according to Bode's Law, another planet, corresponding to Mars,
should have been, there was only a belt of asteroids. Beyond this was
still another belt. And on the other side of the double asteroid belt
was the fourth planet, a fifty-thousand-mile-in-diameter methane-ammonia
giant which Morey named Zeus in honor of Jupiter.

He had picked up a couple of others on his plates, but he had not been
able to tell anything about them as yet. In any case, the planets
Aphrodite and Terra were by far the most interesting.

"I think we picked the right angle to come into this system," said
Arcot, looking at Morey's photographs of the wide bands of asteroids.
They had come into the planetary group at right angles to the plane of
the ecliptic, which had al