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A VOYAGE IN SPACE

these tiny bits of rock. It is quite possible that they have their inhabitants on a small scale; they may be like dolls' houses, which are always most attractive; but we have to make calls at more important dwellings. The main point of our visit was to notice how the gap in Bode's Law was filled, and how it came in consequence to be called Bode's Law; and the next two big planets in the list have also something to say about filling vacant places. There were no more gaps to fill in the middle of the series, but we can have any number of places at the end. Before Uranus and Neptune were discovered the series stopped short at Saturn, with 4 + 96 = 100; and it naturally seemed to confirm the law when Uranus was found by Herschel, and its distance was seen to agree closely with the next term, 4 + 192 = 196. This had a good deal to do with Bode's formation of "the Astronomical Police."

I have already told you of Herschel' s discovery of Uranus, when we were talking about his telescope. He thought at first he had found a comet, and it was not until after some time that the true nature of the discovery became clear. Then it created an immense sensation, for never before in the memory of man had any one found a new planet. All those previously known had been known for ages; they give their names to the days of the week, Satur(n)-day, Sun-day, Mo(o)n-day are called after Saturn, the Sun, the Moon. Our English names for the other days do not remind us of the planets, but the French names (Mar-di for Mars, Mercre-di for Mercury, Jeudi for Jupiter, Vendredi for Venus) are probably known to you. We have for some reason put instead of