Not long ago, the planet Jupiter came among the stars of our southern evening skies. Those who noted down his track found that he first advanced from west to east, then receded along a track near his advancing one, then advanced again, still running on a track side by side with his former advancing track, and so passed away from the scene, toward the part of the sky where the sun's light prevents our tracking him.
That was a useful and rather easy first lesson about the motions of the bodies called planets.
We have now to consider a rather less simple case, but one a great deal more interesting. Two planets intrude among our evening stars, each following a looped track, but the tracks are unlike; the two planets are unlike in appearance, and they are also very unlike in reality.
I hope many of my young readers have already found out for themselves that these intrusive bodies have been wandering among our fixed stars. I purposely said nothing about the visitors last August, so that those who try to learn the star-groups from my maps may have had a chance of discovering the two planets for themselves. If they have done so, they have in fact repeated a discovery which was made many, many years ago. Ages before astronomy began to be a science, men found out that some of the stars move about among the rest, and they also noticed the kind of path traveled in the sky by each of those moving bodies. It was long, indeed, before they found out the kind of path traveled really by the planets. In fact, they supposed our earth to be fixed; and if our earth were fixed, the paths of the planets about her as a center would be twisted and tangled in the most perplexing way. So that folks in those old times, seeing the planets making all manner of loops and twistings round the sky, and supposing they made corresponding loops and twistings in traveling round the earth, thought the planets were living creatures, going round the earth to watch it and rule over it, each according to his own fashion. So they worshiped the planets as gods, counting seven of them, including the sun and moon. Some they thought good to men, others evil. The two planets now twisting their way along the southern skies were two of the evil sort, viz.: Mars, called the Lesser Infortune, and Saturn, called the Greater Infortune. In the old system of star-worship, Mars ruled over Tuesday, and Saturn over Saturday,—the Sabbath of olden times,—a day which the Chaldean and Egyptian astrologers regarded as the most unlucky in the whole week.
FIG. 1. THE PATHS OF MARS AND SATURN.
The actual paths traveled among the stars by these two planets, this fall, are shown in Fig. 1. You will see how wildly the fiery Mars, the planet of war, careers round his great loop, while old Saturn, "heavy, dull, and slow" (as Armado says that lead is—the metal dedicated to Saturn), plods slowly and wearily along. Between August 6 and October 1, Mars traversed his entire backward track,—Saturn, you notice, only a small portion of his much smaller loop. On the sky, too, you will see that while Mars shines with a fierce ruddy glow, well suited to his warlike character, Saturn shines with a dull yellow light, suggestive of the evil qualities which the astrologers of old assigned to him. "My loking," says Saturn, in Chaucer's "Canterbury Tales," "is the fader of pestilence:
"Min ben also the maladies colde,
The derke treasons, and the costes olde;
Min is the drenching in the see so wan,