This is one loop, you will understand, out of an immense number which Mars makes in journeying round the earth, regarded as fixed. He retreats to a great distance, swoops inward again toward the earth, making a loop as in Fig. 2, and retreating again. Then he comes again, makes another swoop, and a loop on another side, and so on. He behaves, in fact, like that "little quiver fellow," a right martialist, no doubt, who, as Justice Shallow tells us, "would about and about, and come you in, and come you in,--and away again would a go, and again would a come." The loops are not all of the same size. The one shown in Fig. 2 is one of the smallest. I have before me a picture which I have made of all this planet's loops from 1875 to 1892, and it forms the most curiously intertwined set of curves you can imagine,--rather pretty, though not regular, the loops on one side being much larger than those on the other. I would show the picture here, but it is too large. One of these days, it will be given in a book I am going to write about Mars, who is quite important enough to have a book all to himself. I want you, now, to understand me that Mars really does travel in a most complicated path, when you consider the earth as at rest. If a perfect picture of all his loopings and twistings since astronomy began could be drawn,--even on a sheet of paper as large as the floor of a room,--the curves would so interlace that you would not be able to track them out, but be always leaving the true track and getting upon one crossing it slightly aslant,--just like the lines by which trains are made to run easily off one track on to another. The unfortunate astronomers of old times, who had to explain, _if they could_, this complicated behavior of Mars (and of other planets, too), were quite beaten. The more carefully they made their observations, the more peculiar the motions seemed. One astronomer gave up the work in despair, just like that unfortunate Greek philosopher who, because he could not understand the tides of the Euboean Sea, drowned himself in it. So this astronomer, who was a king,--Alphonsus of Portugal,--unable to unravel the loops of the planets, said, in his wrath, that if he had been called on by the Creator to assign the planets their paths, he would have managed the matter a great deal better. The plates of the old astronomical books became more and more confusing, and cost more and more labor, as astronomers continued to ... "Build, unbuild, contrive To save appearances, to gird the sphere With centric and eccentric scribbled o'er, Cycle and epicycle, orb in orb."