Uranus is twice as far from the sun as Saturn is, and nineteen times as far as the earth. Its mean distance from the sun is 1,784,732,000 miles, and at this distance more than two hours and a half would be required for light to travel from the sun to the planet. Viewed from the planet, the sun would appear only about two and a half times larger than Jupiter appears to us, and the earth would be a very small telescopic body, if, indeed, it would be visible at all. Even at this great distance from the sun, and with the sun showing so small as it does, the planet would still have more than a thousand times as much light as we get from our moon, and so in this respect might be fairly comfortably provided for even for eyes constructed like those of human beings. The heat the sun’s radiant energy furnishes to Uranus is, from our point of view, almost a negligible quantity. If there were no other source of supply, the normal temperature of the planet would be more than three hundred degrees below zero, Fahrenheit. There is no reason to think, however, that this is the temperature that prevails on Uranus. As far as we can tell, it has a dense and extensive atmosphere, and probably very considerable internal heat. Uranus is smaller than either Jupiter or Saturn; but it is much larger than Mars, Venus, Mercury and the earth combined. Its diameter is nearly thirty-three thousand miles. Its volume is sixty-five times as great as that of the earth; but its mass is only about fourteen times the mass of the earth, which shows it to be a very much expanded body. It is slightly more dense than water, but only about two-tenths as dense as the earth. Its force of gravity is small for so large a body--only about nine-tenths that of the earth. There is every indication that the planet is not a solid body at all, and that it is, perhaps, largely vapor. We undoubtedly cannot see the surface of it; but through the telescope it faintly shows the same belted appearance that we see on Jupiter and on Saturn, though it is difficult to see the belted region, which is near the equator, because the axis of the planet is so inclined to its orbit that much of the time the poles are pointed almost toward us. The spectroscope indicates something of the same materials in its atmosphere that the other large and faraway planets have, and there is no reason to doubt that the planet is in a much earlier stage of development than any of the terrestrial planets.