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"If you turn away from the natural gifts that God has given you, or the universe has given you, you're going to grow old too soon."
- Ray Bradbury
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| Electrified Fence | ||
| A wire fence carrying an electrical charge sufficient to deter crossing the boundary. |
| Well, how have you arranged the fence?"
"I start twelve immensely strong wires--naked, not insulated --from a big dynamo in the cave--dynamo with no brushes except a positive and a negative one--" "Yes, that's right." "The wires go out from the cave and fence in a circle of level ground a hundred yards in diameter; they make twelve independent fences, ten feet apart--that is to say, twelve circles within circles--and their ends come into the cave again." "Right; go on." "The fences are fastened to heavy oaken posts only three feet apart, and these posts are sunk five feet in the ground." "That is good and strong." "Yes. The wires have no ground-connection outside of the cave. They go out from the positive brush of the dynamo; there is a ground-connection through the negative brush; the other ends of the wire return to the cave, and each is grounded independently." "No, no, that won't do!" "Why?" "It's too expensive--uses up force for nothing. You don't want any ground-connection except the one through the negative brush. The other end of every wire must be brought back into the cave and fastened independently, and _without_ any ground-connection. Now, then, observe the economy of it. A cavalry charge hurls itself against the fence; you are using no power, you are spending no money, for there is only one ground-connection till those horses come against the wire; the moment they touch it they form a connection with the negative brush _through the ground_, and drop dead. |
| From A Connecticut Yankee in King Arthur's Court,
by Mark Twain. Published by Not known in 1889 Additional resources -
|
Many sources credit Twain as the earliest source for this idea - but I think there is at least one earlier reference that should count.
In his 1875 epic 20,000 Leagues Under the Sea, Jules Verne writes about electrifying a stair rail or cable to prevent unwanted intrusions onto the Nautilus.
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'A worker replaced by a nubot... had to be compensated.'
'... forcing the energy transfer which allowed him to regrow his lost fingers.'
'The car surged and lifted, clearing its top by a negligible margin.'
Science fiction authors are serious about sleep, too.
'I had explained," said Nessus, "that our civilisation was dying in its own waste heat.'
'Just what did I want Flexible Frank to do? - any work a human being does around a house.'
SF writers have thought about this since the 19th century.
