electricity itself, of course, but elements so prepared that a simple
touch will start into motion a powerful current, able to perform almost
any task I may ask of it. This case, you see, is so small and light that
it is no burden, and yet it contains power enough to serve me for many
days. Of course, all our work of a fixed character has appliances with the
power permanently attached, and these portable reservoirs are carried
about with us only for detached and unexpected tasks."

To my experienced eye the doctor's face looked a little skeptical at this
last remark, and he said:

"But how can the power be applied in these emergencies? Suppose, for
example, it were necessary for you to go from here to the other end of
this vessel in half a second, how would the electricity in your box help
you do it?"

"If I really thought, Doctor, you wanted to be rid of me I would be
tempted to try it; but, as I told your companion just now, you had better
learn all you can of our history before you begin to see what we can do.

"I haven't told you half of the wonders performed by this marvelous power.
It has long been our chief reliance for rapid traveling. You find us in
this ship; but, although navigation is a perfected science, this mode of
traveling is tedious, and ships are used only for pleasure and such out-
of-the-way trips as this. Journeys from place to place over established
routes are made in large tubes, in which the cars are propelled by
electricity. These tubes run both on land and water, being suspended in
the latter a little way below the surface. Both tubes and cars are air-
tight, and the adjustment is so perfect that the cars slide along with the
greatest ease. Riding in an air-tight chamber would not be pleasant if