2. That the Sun is much larger than all the Planets (our Earth included) taken together.
3. That Jupiter is the greatest Planet in our solar system.
4. That Saturn is the second Planet with regard to magnitude.
5. That Herschel ranks third.
6. That the Earth ranks fourth; but that
7. Each of the other Planets and the Moon are smaller than the Earth.
8. That either of the Planets Ceres, Vesta, Juno, Pallas is smaller than the Moon.
§ 11. If you cut a ball or a sphere in halves, and through the centre of one of the flat surfaces, draw a straight line across the whole surface, then this line is called the Diameter of the ball or sphere.—Now as the Sun and the Planets are nothing else but large balls or spheres (Lesson I, § 4), we may also speak of their Diameters.—Thus we say, “the Diameter of the Sun is so many times larger than that of the Earth; the Diameter of Jupiter is so many times larger than that of Venus,” etc.
You will now easily understand what the straight line means, which, in plate No. [III] is drawn through the centre of the circle, which represents the Sun; also the straight lines which are drawn through the circles which represent the Planets.—You will also perceive from the first figure on plate No. [III], that the Sun’s Diameter is larger than the Diameters of all the Planets taken together.
§ 12. Plate No. [IV] represents the surfaces of the Planets, compared to that of the Sun.—For you must know that it is possible to measure the surface of a sphere; which is done by supposing it to be spread out, and then seeing how many square inches, feet or yards it contains. This we have supposed to be done with the surfaces of the Sun and Planets, and accordingly, have drawn their square measurements, in Plate No. [IV]. in proportion to each other.