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Consider the following experiment.
You have two pieces of metal – copper and zinc –
which you connect to conducting wires.
And you then submerge the metals in an electrolyte –
in this case, vinegar.
You will observe that bubbles will form around the zinc –
but not on the copper.
The metals seem dissimilar in this way.
And if you then connect the two wires holding the metals,
Tiny bubbles begin to form around the copper terminal.
It seems as though something is being
pulled from the zinc, through the wire –
allowing a reaction to occur on the copper side.
And it turns out [that] this is a flow of electrical charge –
as electrons are pulled away from the zinc, towards
the copper, through the conductive path in the wire.
Think of this flow as the result of a charge imbalance –
or 'electrical pressure' – between the two metals –
as compared to the instantaneous discharge observed
with static electricity experiments.
And towards the end of the 18th century,
Alessandro Volta had been investigating this effect.
he found that chaining these cells together,
would amplify this flow of charge.
By 1800, he simplified things even further –
removing the jar – which provided more electrolyte
than was actually needed.
He writes: "[using] a few dozen small round
disks of copper (pieces of coin for example)
and [an] equal number of plates of zinc,
I prepare circular pieces of spongy matter
capable of retaining water.
I continue coupling a plate of copper with one [of] zinc,
and always in the same order,
and interpose, between each of these couples,
a moistened disk.
This continues until I have a column
as high as possible, without danger of it falling."
This is known, famously, as the 'voltaic pile' –
the first battery in history to provide
a continuous flow of electrical charge – or 'current.'
More cells resulted in an increased
'electrical pressure' at the two ends.
And 'electrical pressure' was an early term
for what we now call 'voltage' – after Volta.
Now, if the two leads of a voltaic pile were brought into
direct contact, a series of shocks could be observed.
Now, at first, the utility of electric current
as a communication method was not immediately obvious,
aside from [its ability to produce] faint sparks and bubbles.
One idea was to use
the presence of bubbles to signal letters.
And the 'bubble telegraph' used this method –
though it involved 26 difference circuits –
one for each letter.
And it was based on the fact that the battery providing
the current can be placed at a distance,
away from the jars containing the leads
creating the bubbles –
an inventive, although clumsy, system,
which was never adopted.
But very soon, everything changed,
after a famous demonstration in 1819.
It was found that if we simply pass a wire
near a compass, and connect it to a battery,
as soon as the wire made contact with the battery,
the needle jumped – without any physical contact.
The only explanation was that the current-carrying wire
was creating a temporary magnetic 'field.'
This was followed by a series of tests
to figure out the direction of this field.
First, we assumed it was pointing along the wire –
with the current – or perhaps,
emanating outwards from the wire – as heat would travel.
But eventually, it was deduced that it must be traveling
around the wire – in perpendicular circles.
So, a loop of wire would create a magnetic field
which points through the center of the loop,
and around the outside.
This led to the 'galvanometer,' which was designed
to detect – and measure – electrical current.
And it was just simply a coil of wire,
with a compass suspended in the center.
Now, when electric current was applied to the coil,
a magnetic field would push through
the middle of the coil, and around the outside.
So the needle would always point
perpendicular to the direction of the force,
which was balanced on either side of the needle.
And the stronger the current,
the stronger the deflection of the needle.
By 1824, William Sturgeon demonstrated a way
to increase the strength of this field even more.
Simply by wrapping a coil of wire
around a piece of iron – such as a nail –
a magnetic force could be amplified –
because iron seemed to be a better medium
for supporting the formation of magnetic fields.
We call this 'permeability.'
And by wrapping a wire many times,
the strength of the field could be
amplified thousands of times.
And this [kind of device] is known as an 'electromagnet.'
So, suddenly, it was possible to create magnetic fields –
which could move needles with precision and force –
using electric current applied at a distance –
using a long loop of wire, and a strong battery.
At the time, our understanding
of information was in its infancy.
People were thinking about information in a message
as the number of letters in a message.
So the goal was intuitive.
Who could come up with the fastest way to transmit letters?
Whoever had the fastest system would, therefore,
reduce the cost per message
for the sender using the system.
And a gold mine was waiting for whoever got there first.
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