are really more than 3,000 stars among the Pleiades.
Some of them can be seen only with the biggest telescopes. Others are
revealed only by the spectroscope. And some can be found only by means
of photography.

But the most amazing thing about the Pleiades is the distances between
them. They look so close together that you would probably say "the moon
seems bigger than all of them put together." Sometimes the moon comes
near the Pleiades, and you expect that the moon will blot them all out.
But the astronomers say the full moon sails through the Pleiades and
covers only one of them at a time, as a rule. They even say it is
possible for the moon to pass through the Pleiades without touching one
of them! I should like to see that. If anything like it is going to
occur, the magazine I spoke of in the first chapter will tell me about
it. And you'd better believe I will stay up to see that, if it takes all
night!

There are two more constellations in the southern part of the sky that
ought to be interesting, because they are the two hunting dogs that help
Orion fight the Bull. But I can't trace these animals, and I don't
believe it is worth while. The brightest stars in them everybody can see
and admire--Sirius, the Bigger Dog, and Procyon, the Smaller Dog.

Every one ought to know Sirius, because he is the brightest star of all.
(Of course, he is not so bright as Venus and Jupiter, but they are
planets.) To find him, draw a line from the eye of the Bull through the
belt of Orion and extend it toward the southeast about twenty degrees.
They call him the Dog star because he follows the heels of Orion. And
people still call the hottest days of summer "dog days" because 400
years before Christ the Romans noticed that the Dog star rose just
before the sun at that time. The Romans thought he chased the sun across
the sky all day and therefore was responsible for the great heat. But
that was a foolish explanation. And so is the old notion that dogs are
likely to go mad during the dog days "because the dog star is in the
ascendant." So is the idea that Sirius is an unlucky star.

There are no lucky or unlucky stars. These are all superstitions, and we
ought to be ashamed to believe any superstition. Yet for thousands of
years before we had public schools and learned to know better, people
believed that every one was born under a lucky star or an unlucky one,
and they believe that farmers ought to plant or not plant, according t