Yes; some planets are much nearer the sun than others. Which planet is nearest the sun? The planet called Mercury. Which is next to Mercury? The planet called Venus. And which is third in distance from the sun? Our own planet, the Earth. Are there any planets still farther from the sun? Yes; Mars, Jupiter, Saturn, Uranus, and Neptune, and many smaller planets. How does each planet move? It moves in its own track or orbit around the sun, as is represented in Fig. 2. [Illustration: Fig. 2.] Does the earth always move in the same orbit around the sun? Yes; the earth moves in the same orbit around the sun, year after year. How long does it take the earth to move around the sun? 365 days, 5 hours and 49 minutes, or one year. What makes a year to us? A year to us is the time required by the earth to move around the sun. If the earth is in a certain place at noon, on New Year’s day, when will it be in that place again? 5 hours and 49 minutes after noon on New Year’s day of the next year. What, then, does the earth do every year? The earth moves around the sun and comes back to the place whence it started, once every year. Has the earth any other motion than the one around the sun? It has; it turns over and over. Does the earth stay in one place as it turns over and over? It does not; it moves on in its track around the sun. How many times does it turn over while going around the sun? Three hundred and sixty-five times. How many times, then, does it turn over in one year? The earth turns over three hundred and sixty-five times in a year. What is the time which it takes to turn over once called? It is called a day. How many days in a year? There are three hundred and sixty-five days in a year. What two motions, then, has the earth? It turns over and over, and at the same time it moves around the sun. What change is produced on the earth by its moving around the sun? The change of Seasons. Will you name the seasons? Winter, Spring, Summer, and Autumn. Do they follow each other in regular order? They do; Spring follows Winter, Summer follows Spring, Autumn follows Summer, Winter follows Autumn, and Spring follows Winter again. How often have we these seasons? As often as the earth moves around the sun, which is once a year. What change is produced on the earth by its turning over? The change of day and night. Where is it day? It is day on that part of the earth which is turned towards the sun. Where is it night? It is night on that part of the earth which is turned away from the sun. How often do we have the change from day to night? As often as the earth turns over, which is once in twenty-four hours. What is a day? A day is the time from sunrise till sunrise again, from sunset till sunset again, from noon till noon again, or from midnight till midnight again. What does a day include? It includes the night-time as well as the day-time, of the twenty-four hours.