But if you could spin and throw a top far enough away from the Earth so that it would not meet with friction or resistance of any kind, it would go on spinning forever just like the planets. =How to Plot the Position of a Planet.=—One of the tests which a Boy Scout must pass in order to obtain a merit badge for starcraft is to “plot on at least two nights per month for six months the positions of all naked eye planets between sundown and one hour thereafter. The plot of each planet shall contain at least three fixed stars with their names and designations, colors of planets and stars to be recorded by him.” Now, by looking at your almanac under the head of Morning and Evening Stars you will find all the planets which are listed as Evening Stars, together with the dates when they can best be seen. From your almanac for 1915 you will learn that _Mercury_ is an evening star, and can be seen about Feb. 5, May 31 and September 27 in the west, just after sunset; that _Venus_ will be an evening star from September 12 for the rest of the year; that _Jupiter_ will be an evening star until February 24; after that a morning star until September 17, and then an evening star for the rest of the year, and that _Saturn_ will be an evening star until June 28. The first thing to do is to find what constellation is on your _meridian_ at 9 P. M. for the month that the planet you wish to plot is to be seen. This you can do by looking at the map of the stars shown in Fig. 67. You can see any of the stars or constellations on your meridian by looking for them at 9 o’clock P. M. on the months marked above them. This done, consult your almanac and find out what time the Sun sets on the day that the planet you are looking for can be seen. As an example let’s take Mercury, which the almanac says is an evening star about February 5, and which can be seen in the west just after sunset. The almanac will also tell you that the Sun sets on February 5 at 5 o’clock. [Illustration: FIG. 67.—MAP OF STARS ON SUN’S PATH.] The star map (Fig. 67) will show you that the constellation of _Gemini_, the Twins, is one which can be seen in February on your meridian at 9 o’clock at night, and you know that Mercury can be seen close to the western horizon from 3 to 4 hours earlier. Since Gemini, the Twins, is on the meridian at 9 o’clock, _Taurus_, the Bull, which is the next constellation to it, will be on the meridian at 7 o’clock, and _Aries_, the Ram, will be on the meridian at 5 o’clock. Now the next constellation to the west of Aries, the Ram, is _Pisces_, the Fishes, and the next one to Pisces, the Fishes, is _Aquarius_, the Water Bearer, and as this constellation sets about an hour after the Sun, it is in this constellation that you will find Mercury in the early February evenings. [Illustration: FIG. 68.—DIAGRAM OF POSITION OF CONSTELLATIONS.]