I can see only six of them, and there is a famous old tale about the "lost Pleiad." But I needn't describe them. Every child finds them by instinct. Some compare them to a swarm of bees; some to a rosette of diamonds; some to dewdrops. But I would not compare them to a dipper as some do, because the real Little Dipper is very different. The light that seems to drip from the Pleiades is quivering, misty, romantic, magical. No wonder many children love the Pleiades best of all the constellations. No wonder the poets have praised them for thousands of years. The oldest piece of poetry about them that I know of was written about 1,500 years before Christ. You can find it in the book of Job. But the most poetic description of the Pleiades that I have ever read is in Tennyson's poem "Locksley Hall," in which he says they "glitter like a swarm of fireflies tangled in a silver braid."
There are a great many old tales about the lost Pleiad. One is that she veiled her face because the ancient city of Troy was burned. Another story says she ceased to be a goddess when she married a man and became mortal. Some people think she was struck by lightning. Others believe the big star, Canopus, came by and ran away with her. Still others declare she was a new star that appeared suddenly once upon a time, and after a while faded away.
For myself, I do not believe any of these stories. One reason why I don't is that a seventh star is really there, and many people can really see it. Indeed, there are some people so sharp-eyed that on clear nights they can see anywhere from eight to eleven. And, what is more, they can draw a map or chart showing just where each star seems to them to be.
But the most wonderful stories about the Pleiades are the true stories. One is that there 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 to the size of the moon. Now we know that is all bosh. Those old superstitions have done more harm than good. One of the most harmful was the belief in witches. Let us resolve never to be afraid of these old tales, but laugh at them.
Why should anybody be afraid of anything so lovely as Sirius? I used to think Sirius twinkled more than any other star. But that was bad reasoning on my part. I might have noticed that every star twinkles more near the horizon than toward the zenith. I might have noticed that stars twinkle more on clear, frosty nights than when there is a little uniform haze. And putting those two facts together I might have reasoned that the stars never really twinkle at all; they only seem to. I might have concluded that the twinkling is all due to the atmosphere—that blanket of air which wraps the earth around. The nearer the earth, the thicker the air, and the more it interferes with the light that comes to us from the stars.
They say that Sirius never looks exactly alike on two successive nights. "It has a hundred moods," says Mr. Serviss, "according to the state of the atmosphere. By turns it flames, it sparkles, it glows, it blazes, it flares, it flashes, it contracts to a point, and sometimes when the air is still, it burns with a steady white light." (Quotation somewhat altered and condensed.)