The heavy black line drawn lengthwise through the middle of the strip in Fig. 172 represents the line of the ecliptic which is the yearly path the Sun seems to take. The planets also take the same course, though they may be on one side or the other of the Sun’s path by 8 degrees, thus making the zodiac 16 degrees wide; hence, the lighter parallel lines on either side of the black line, or path of the Sun, is the farthest away that the planets ever get. If you were to cut the strip of paper, Fig. 172, out of the book and paste the ends together, you would have a band, or circle representing the zodiac more nearly as it is; but instead of cutting the book you had better draw the signs and constellations on a strip of cardboard 2 inches wide and 24 inches long and glue the ends together, as shown in Fig. 173; you will now have a zodiac with which you can do a little experimenting. [Illustration: FIG. 173.--CARDBOARD ZODIAC.] Place a candlelight in the center of the cardboard ring and suspend a marble from a thread, by means of a drop of sealing wax, and let the marble hang between the light and the cardboard zodiac. As seen from the marble, which represents the earth, the candle, representing the sun, is in the constellation directly opposite the one in which the shadow of the marble falls. In the almanacs our year begins with January and as the Sun is then in the sign Aquarius, this month is represented by a picture of Aquarius, the Water Bearer; but in marking out the signs of the zodiac on a flat strip of paper we begin with Aries, which the Sun enters in the month of March, and read them from right to left. The reason for this is because the Earth travels round the Sun counter-clockwise as seen from the north and this makes the Sun appear to move eastward through the constellations of the zodiac. [Illustration: FIG. 174.--CONSTELLATIONS OF ZODIAC IN CIRCLE.] This makes all the months follow each other in the proper order when the strip of paper is glued together, as shown in Fig. 173, or when the constellations are arranged in a circle, as shown in Fig. 174. This latter diagram shows plainly that when the Earth is at that part of its orbit marked A the constellation of Taurus is back of the Sun. If we are on that side of the Earth which is toward the Sun of course we cannot see Taurus for the Sun, which is shining in our eyes. Still Taurus is the background of the Sun just the same, and so when the almanac says the Sun is in Taurus you will know that the Sun is directly between the Earth and Taurus. The same thing is true of all the planets. Take Mars, for example; whenever Mars is in that part of its orbit so that we can see it at night, as shown at B, Fig. 172, we also see the constellation back of it--in this case it is Libra, the Balance--and since a planet and a fixed star look exactly alike to the naked eye it is easy to think of Mars as being in that constellation; and it is the same with all the other planets.