y were longer than cylinders, thirty feet in
diameter, and there was a group of four main machines fully a hundred
twenty feet long! There were many smaller mechanisms--yet these smaller
ones would easily have constituted a complete power supply for the
average big city. Along each wall ran a bank of transformers, cast in
the same heroic mold. These seemed connected with the smaller machines,
there being four conductors leading into each of the minor units, two
intake, and two, apparently, output leads, suggesting rotary converters.
The multiple units and the various types and sizes of transformers made
it obvious that many different frequencies were needed. Some of the
transformers had air cores, and led to machines surrounded with a
silvery white metal instead of the usual iron. These, apparently, were
generating current at an extremely high frequency.

"Well," Morey commented, "they ought to have power enough. But do you
notice that those four main units have their leads radiating in
different directions? The one on the left there seems to lead to that
big power board at the front--or better, bow. I think it would be worth
investigating."

Arcot nodded. "I had the same idea. You notice that two of the main
power units are still working, but that those other two have stopped?
Probably the two dead ones have something to do with the motion of the
ship. But there's one point I think is of even greater interest. All the
machines we have seen, all the conspicuous ones, are secondary power
sources. There are no primary sources visible. Notice that those two
main conduits lead over to the right, and toward the bow. Let's check
where they go to."

As they talked they followed the huge conductors back to their point of
convergence. Suddenly they rounded one of the huge main power units, and
saw before them, at the center of square formed by these machines, a low
platform of transparent light-metal. At the exact center of this
platform, which was twenty feet in diameter, there was a table, about
seven feet across and raised about five feet above the level of the
platform on stout light-metal legs. On the table were two huge cubes of
solid silver, and into these cubes ran all the conductors they had seen.

In the space of about six inches left between the blocks of metal, there
was a small box constructed of some strange new material. It was the
most perfect reflecting surface that any of the men had ever imagined.
Indeed,