Roughly speaking he is about 490,000,000 miles distant from the sun and his periodical revolution is about twelve Earth-years, his enormous bulk is about 1400 times greater than Earth and his day and night about ten Earth-hours. He travels in his orbit at over 29,000 miles per hour, and the equatorial parts rotate at 28,000 miles an hour. At the time the _Regina_ was christened, in the old days, the days of King Edward the Seventh, Jupiter had six moons—the _Regina_ gave him another, the one she had stolen—making seven: since then six more had been discovered, and the travellers saw there were four others, making in all, seventeen; this alone was worth coming for. Also as they drew nearer they saw that his equatorial velocity of rotation, compared with Earth, was so great that if they landed they would be so light as to be flung off into space and it would be necessary for them to be made heavier, but if this were done, would their physical strength enable them to bear the increased weight, and would the extra atmospheric pressure so oppress them as to cause congestion of the brain, or in other ways be fatal? However, the risk had to be taken, otherwise it would be difficult to get the insects they had come so far to obtain, if they were unable to leave the vessel. Whilst they were discussing the point they were drawing sufficiently near to elucidate several controversial matters. For centuries it had been thought that the belts of Jupiter were vapour or clouds and nothing more, but now the voyagers distinctly saw what would be hidden and probably unknown to the Jovians themselves, who from their position on the underside of their atmosphere could not be aware of its appearance as seen from the outside. It was unmistakable that the belts were caused by millions of fine particles, like dust, which were constantly coming through the atmosphere, being of too little gravity to remain on the planet, the rapid revolution of which flung them off into space by centrifugal force, and reaching the outside, they revolved round the planet’s atmosphere at a distance of over a thousand miles; these particles were coming from all parts of the planet, eventually to become attracted to one or other of the belts on which they settled. These belts were consequently slowly widening, though they remained isolated and distinct by their own force of gravity and repulsion and were visible to Earth, with an addition of but a few inches in each century.