Redgrave checked the R. Force and the _Astronef_ fell obliquely across the pole towards the equator. As they approached the luminous clouds Redgrave turned it on again, and they sank slowly through a glowing mist of innumerable colours, until the surface of Ganymede came into plain view about ten miles below them. What they saw then was the strangest sight they had beheld since they had left the Earth. As far as their eyes could reach the surface of the Ganymede was covered with vast orderly patches, mostly rectangular, of what they at first took for ice, but which they soon found to be a something that was self-illuminating. "Glorified hot-houses, as I'm alive," exclaimed Redgrave. "Whole cities under glass, fields, too, and lit by electricity or something very like it. Zaidie, we shall find human beings down there." "Well, if we do I hope they won't be like the half-human things we found on Mars! But isn't it all just lovely! Only there doesn't seem to be anything outside the cities, at least nothing but bare, flat ground with a few rugged mountains here and there. See, there's a nice level plain there near the big glass city, or whatever it is. Suppose we go down there." Redgrave checked the after engine which was driving them obliquely over the surface of the satellite, and the _Astronef_ fell vertically towards a bare, flat plain of what looked like deep yellow sand, which spread for miles alongside one of the glittering cities of glass. "Oh, look, they've seen us!" exclaimed Zaidie. "I do hope they're going to be as friendly as those dear people on Venus were." "I hope so," replied Redgrave, "but if they're not we've got the guns ready." As he said this about twenty streams of an intense bluish light suddenly shot up all round them, concentrating themselves upon the hull of the _Astronef_, which was now about a mile and a half from the surface. The light was so intense that the rays of the Sun were lost in it. They looked at each other, and found that their faces looked almost perfectly white in it. The plain and the city below had vanished. To look downwards was like staring straight into the focus of a ten thousand candle-power electric arc lamp. It was so intolerable that Redgrave closed the lower shutters, and meanwhile he found that the _Astronef_ had ceased to descend. He shut off more of the R. Force, but it produced no effect. The _Astronef_ remained stationary. Then he ordered Murgatroyd to set the propellers in motion. The engineer pulled the starting-levers, and then came up out of the engine-room and said to him: "It's no good, my Lord; I don't know what devil's world we've got into now, but they won't work. If I thought that engines could be bewitched----"