These are some of Faraday's
objects that we've got on
display in our collections.
I'm interested in fluorine,
because it represents one of
the very few failures that
Michael Faraday-- who worked
in their Royal Institution, in
the early part of the 19th
century, made.
In 1834 and 1835 he sought to
isolate fluorine using the
sorts of electro-chemical
techniques that Davy used to
isolate sodium potassium a
generation or so before.
Faraday was an extraordinary
meticulous worker.
He kept a very detailed set
of laboratory notes which
ultimately ran to
just over 16,000
paragraphs, that he numbered.
Fluorine is an extraordinarily
reactive substance.
It was first discovered--
well, the mineral which contains
fluorine was first
discovered in late
18th century.
And people sought to try and
isolate fluorine for the
following 50 years.
And in 1834 and 1835, Faraday
spent a huge amount of time
trying to isolate fluorine
for the first time.
This is his entry for the 10th
of February, 1834, paragraph
1477, starting with
the wonderful
line, "Worked for fluorine.
Used a small strong platina
vessel, like a little
crucible, and having made a tube
of platina soldered by
gold, soldered it
onto the former.
Adjusted a thick, plat wire,
P, so as to go into it.
Touching nowhere, but dipping
into fused fluoride of lead,
which was kept in that state
within by the heat of a spirit
lamp without."
And what Faraday basically honed
in on, as a method to
try and isolate fluorine, was
to heat up lead fluoride.
And it's really surprising that
when he got molten lead
fluoride he didn't die as a
consequence, as they are both
really nasty materials.
And then use electrolysis to
try and dissociate the
fluorine out of the compound.
So here you have this spirit
lamp down there taking off
electric current--
positive pole there, negative
pole there,
But the problem with
fluorine is it's
such a reactive substance.
As soon as it was liberated it
would react with another gas,
like oxygen, for example.
And so Faraday never ever
got pure fluorine.
And indeed, it was such a
difficult problem that it took
another 50 years before Henri
Moissan, a French chemist, in
1886 isolated fluorine
for the first time.
And for that he won
the Nobel Prize in
the early 20th century.
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