(string music playing)
- The internet has been referred to
as a series of tubes,
but long before e-mail
people transmitted messages rapidly
across cities through
networks of penumatic tubes.
These are pipelines that use air pressure
to propel canisters
from point a to point b.
You can still see them at
the drive through windows
of some banks and
pharmacies, but when I say
long before e-mail, I don't
mean the way groovy 60's, man
or even the rip roaring
20's, I'm talking about
the mid 1800's, which I don't
have a specific accent for.
The idea of using pressurized gas
to produce mechanical
motion goes all the way back
to a Ptolemaic Greek mathematician called
Hero of Alexandria, but the first
practical application of the concept
sped mail and telegrams though London
starting in the 1850's.
By 1886, London had 34 miles of mail tubes
underneath the city transmitting
32,000 messages a day
at up to 51 miles per hour.
Cities like New York, Boston,
Paris, Berlin and Vienna
had similar systems by
the turn of the century,
though the World Wars and the
growing automobile industry
shut most of them down by the 1950's.
The technology is still in use today
to transport materials
through manufacturing plants,
medical samples through hospitals,
and your bank deposit slips to you,
but how, you demand of
your computer screen?
Well, it's inanimate and I'm pre-recorded
but I've got the answer for you anyway.
These pneumatic systems
start with an air tight tube
with seal-able hatches at either end.
You put your thing what needs transporting
in a canister that's smaller
than the tube that has
flexible skirts on
either end that can form
to the interior edges of the tube.
You put your canister in a hatch
and press the go button.
The button activates a
motor at the other end
of the tube which opens a vent
and turns on a fan.
The fan drives particles of air
from the tube, out through the vent
and into the wild blue yonder,
thus creating a difference in the density
of the air in front of the
canister and behind it.
The denser air behind the canister
pushes it to its destination.
A trap door closes behind the canister,
the motor stops breaking
the partial vacuum
created in the tube by the fan
and your buddy can open the
hatch and take the canister.
It's basically the same thing that happens
when you drink through a straw.
Your suction creates
an area of low pressure
at the top of the straw.
The higher pressure liquid at the bottom
pushes a sip up into your face.
Of course that's the simple version.
Complex pneumatic systems may have dozens
of branching tubes containing switches
and transfer points that house extra fans.
By using computer systems
to carefully regulate
the fans, and thus, the air pressure,
even delicate lab samples
can arrive safely.
So, I've got a question for you.
Do you think it's time for a
pneumatic mail tube revival?
Let me know in the comments.
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and for lots more technological knowledge,
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