One object on Jupiter, the great "+Red Spot+," has been under observation since 1878, and possibly for 200 years before that. It is a large, oval object fitted in a frame of the same shape. The spot itself has often faded and been lost since 1878, but the frame has remained. The spot is in size and position relative to Jupiter much as Australia is to the Earth, but while Australia moves solidly with the rest of the Earth in the daily rotation, neither gaining on South America nor losing on Africa, the Red Spot on Jupiter sees many other spots and clouds pass it by, and does not even {78} retain the same rate of motion itself from one year to another. No other marking on Jupiter is so permanent as this. From time to time great round white clouds form in a long series as if shot up from some eruption below, and then drawn into the equatorial current. From time to time the belts themselves change in breadth, in colour, and complexity. Jupiter is emphatically the planet of change. And such change means energy, especially energy in the form of heat. If Jupiter possessed no heat but that it derived from the Sun, it would be colder than Mars, and therefore an absolutely frozen globe. But these rushing winds and hurrying clouds are evidences of heat and activity--a native heat much above that of our Earth. While Mars is probably nearer to the Moon than to the Earth in its condition, Jupiter has probably more analogies with the Sun. The one unrivalled distinction of SATURN is its Ring. Nothing like this exists elsewhere in the solar system. Everywhere else we see spherical globes; this is a flat disc, but without its central portion. It surrounds the planet, lying in the plane of its equator, but touches it nowhere, a gap of 7000 miles intervening. It appears to be circular, and is 42,000 miles in breadth. Yet it is not, as it appears to be, a flat continuous surface. It is in reality made up of an infinite number of tiny satellites, mere dust or pebbles for the most part, but so numerous as to look from our distance like a continuous ring, or rather like three or four concentric rings, for certain divisions have been noticed in it--an inner broad division called after its discoverer, CASSINI, and an outer, fainter, narrower one discovered by ENCKE. The innermost part of the ring is dusky, fainter {79} than the planet or the rest of the ring, and is known as the "crape-ring." Of Saturn itself we know little; it is further off and fainter than Jupiter, and its details are not so pronounced, but in general they resemble those of Jupiter. The planet rotates quickly--in 10 h. 14 m.--its markings run into parallel belts, and are diversified by spots of the same character as on Jupiter. Saturn is probably possessed of no small amount of native heat.