The million-monkey method
Thomas Alva Edison is often called an `electrical genius' or `the wizard
of Menlo Park' (Edison's labs were in Menlo Park, New Jersey, and later
in Menlo Park, California). It is certainly true that Edison's company
either invented or promoted quite a few things electrical. Edison
held an enormous number of patents. But in my opinion, he was not
really a genius at all, at least not with regards to electricity and energy.
He was not terribly well-educated, and his approach -- which he himself
described as `1% inspiration and 99% perspiration' -- was something of
the `shotgun method': fire lots of small pellets and hope that one
of them hits the target. For instance, when working on the electric
light bulb, he had an assistant test over 1000 separate filament materials.
Someone else did all the hard work; Edison just put up the cash, collected
the credit, and held the patents.
Nikola Tesla, on the other hand, was definitely a genius -- and a nut.
He came up with the concept for three-phase AC as a teenager in Eastern
Europe. (According to a biography I read, the idea just sprang
into his head one day.) He went to an actual university and studied
actual electrical theory. He would decide to build something, work
out the details -- usually in his head -- and then build it and it would
just work. He had no business sense at all, though; after coming
up with a simple, reliable, reasonably-efficient and sensible method of
generating, transmitting, and using electricity, he sold the patents to
George Westinghouse. Today `Westinghouse' is a famous brand name,
while `Tesla' is known only for his coils.
The AC/DC wars
In any case, back in the early days of electrification, Edison and Tesla
(and of course Westinghouse) became involved in propaganda wars.
Edison held patents on Direct Current systems, while Westinghouse held
patents on Alternating Current. DC was easier for any ordinary
uneducated slob to understand, of course -- it required no calculus, nor
the sort of `mental vision' of voltage and current flows creating rotating
magnetic fields that would spin a motor -- but AC clearly held the technical
edge for centralized power generation and long-distance transmission.
Either worked fine for simple applications like lighting (although something
called the `Edison effect' made light bulbs burn out at one end and thus
not last as long as with AC), but AC's easy transformability made it far
more practical. To use DC, one would have to put a coal-burning generator
on every street corner. Edison no doubt saw his patents becoming
worthless, and set out to demonize AC.
The first electric chair execution, held in upstate New York, used AC.
Exactly why, I am not sure. It is true that AC, especially around
50 to 60 Hz, can paralyse muscles; it causes them to lock up, so that someone
who accidentally gets hold of two bare high-voltage wires can find himself
unable to let go. DC tends to cause a more `one-way' contraction.
Either can kill, but without the `locked muscle' effect, it is easier to
free oneself of a DC current. (An old electrician's trick, by
the way, is to test a supposedly-dead circuit using the back of
the hand, rather than a finger-tip. If the circuit is still energized,
the hand will clench shut, because the finger-closing muscles are stronger
than the finger-opening ones. The clenched-shut hand will tend to
jerk away from the wire, rather than grabbing hold of it. It is an
old electrician's trick because the young ones who use it and get shocked
live to become old electricians....)
In any case, in what amounted to a publicity stunt, Edison arranged
for news reports on the `killer AC' that his competitors planned to string
up all over the city of New York. Despite this, AC was so obviously
superior that it won out anyway.