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188 the satellites of the Georgium Sidus, when, after throwing aside the speculum, they stood broad before us."

From observations continued on Uranus for fifteen years, Herschel first suspected, and then became convinced that other satellites besides the two, which he discovered in 1787, attend the planet on its journey round the sun. It was labour of love not lost, or grudgingly given, but the fruits it yielded were Dead Sea apples with a fair outside and rottenness within. He believed he saw other four moons circling round Uranus apparently in an opposite direction to other planets, that is, from east to west, not from west to east. He also suspected that it had a ring round it, or two rings; then he gave up the idea; then he entered in his journal, "When the satellites are best in focus, the suspicion of a ring is the strongest"; and nine months after he adds, "The planet is not round, and I have not much doubt but that it has a ring." He used "successively powers rising from 240 to 2400," more than two years after, "without any suspicion of a ring." A fortnight later he tried magnifying powers of 2400 and 4800. In conclusion he believed in the four new satellites, but gave the ring up. A traveller in unexplored regions of the heavens may thus be as much the victim of a mirage as a wanderer in the thirsty deserts of earth. But a singular thing was observed: these moons of Uranus became invisible when they approached the planet, which those of Jupiter and Saturn never did till the planet got between them and us. What was the reason?

The cause is in the eye of the observer himself. It requires to adapt itself to the light which falls on the