"Solar generators, tide-motors, and wave-motors, all at once!" ejaculated Seaton. "_Some_ power-plant! Folks, I'm going to take a look at that if I have to drill in with a ray!"
[Illustration: Some power plant! Folks, I'm going to take a look at that....]
They circumnavigated the island without revealing any door or other opening--the entire thirty miles was one stupendous battery of the generators. Back at the starting point, the _Skylark_ hopped over the structure and down to the surface of the small central lagoon previously noticed. Close to the water, it was seen that there was plenty of room for the vessel to move about beneath the roof of reflectors, and that the island was one solid stand of tide-motors. At one end of the lagoon was an open metal structure, the only building visible, and Seaton brought the space-cruiser up to it and through the huge opening--for door there was none. The interior of the room was lighted by long, tubular lights running around in front of the walls, which were veritable switchboards. Row after row and tier upon tier stood the instruments, plainly electrical meters of enormous capacity and equally plainly in full operation, but no wiring or bus-bar could be seen. Before each row of instruments there was a narrow walk, with steps leading down into the water of the lagoon. Every part of the great room was plainly visible, and not a living being was even watching that vast instrument-board.
"What do you make of it, Dick?" asked Crane, slowly.
"No wiring--tight beam transmission. The Fenachrone do it with two matched-frequency separable units. Millions and millions of kilowatts there, if I'm any judge. Absolutely automatic too, or else----" Seaton's voice died away.
"Hold it, Dicky! Remember I had to put you to bed after that last hunch you had!"
"Here it is, anyway. Mart, what would be the logical line of evolution when the planet has become so old that all the land has been eroded to a level below that of the ocean? You picked us out an old one, all right--so old that there's no land left. Would a highly civilized people revert to fish? That seems like a backward move to me, but what other answer is possible?"
"Probably not to true fishes--although they might easily develop some fish-like traits. I do not believe, however, that they would go back to gills or to cold blood."