This article was taken from the November 2014 issue of WIRED magazine. Be the first to read WIRED's articles in print before they're posted online, and get your hands on loads of additional content by subscribing online.
Long before tiny silicon components, the Victorians were using telegraph signals to communicate across vast distances almost instantaneously. Next time you're ever stuck somewhere with no signal, rustle up a primitive internet with the help of Lewis Dartnell, author of The Knowledge: How to Rebuild our World from Scratch (Random House, £20). Leila Johnston
Roll your own copper wire"This element is very easy to smelt," says Dartnell. "Crush some copper ore and mix it with ground charcoal -- it's a reducing agent that will strip away the oxygen, leaving pure metal.
Mix in some potash crystals (evaporated out of wood-fire ash) to help the metal melt." Your soft copper can be easily pulled into wire, ready to conduct electricity.
Build a simple battery "If you can immerse two differently reactive metals in a conducting solution -- or 'electrolyte' -- you'll soon find yourself with a dependable power source," Dartnell explains. "A pencil and some rolled-up aluminium foil should work for the positive and negative terminals, and salt water would do the trick for a conducting solution," he adds.
Connect your magnetAn electromagnet is simply copper wire wrapped into a coil around a cylindrical core of iron (eg a nail). "When switched on, the coil produces a strong magnetic field from even feeble currents," says Dartnell. "It's ideal for a message transmitted down a stretch of wire."
Construct your internetString your length of copper wire between two locations, earthed at each end. "Connect a battery and switch at one end, to send a controlled current down the wire," says Dartnell. "Your electromagnet at the other end will detect the signal, and with a Morse code book in one hand, you'll be ready to send your first basic message."
Create a relay system "Balance a metal level over the electromagnet so that it is attracted downwards," suggests Dartnell. "Then use this to close a second circuit with its own battery, and then you need to add a light or a buzzer to each end to reveal the signal that's travelling along your wire."
This article was originally published by WIRED UK
