1
00:00:02,960 --> 00:00:07,800
In 1807, maverick Cornish chemist
Humphry Davy

2
00:00:07,800 --> 00:00:11,560
attempted something
no one had dared try before.

3
00:00:13,000 --> 00:00:17,000
He harnessed a newly discovered
force, electricity,

4
00:00:17,000 --> 00:00:21,400
to rip apart a caustic chemical
called potash.

5
00:00:21,400 --> 00:00:23,920
And he discovered a new element.

6
00:00:27,000 --> 00:00:30,160
Vivid, violent potassium.

7
00:00:33,160 --> 00:00:40,560
Davy had found a new way of
cracking open the natural world
to reveal its building blocks.

8
00:00:42,760 --> 00:00:47,760
This is the story of one of
the biggest questions there is.

9
00:00:47,760 --> 00:00:51,280
What is everything
in our world made of?

10
00:00:53,760 --> 00:00:59,760
The quest to find out would
ultimately lead to
an extraordinary insight -

11
00:00:59,760 --> 00:01:05,680
that everything,
from the diversity of nature
to the complexity of man,

12
00:01:05,680 --> 00:01:09,000
was made from just 92 elements.

13
00:01:12,840 --> 00:01:14,800
'I'm Jim Al-Khalili.

14
00:01:14,800 --> 00:01:20,640
'I've studied physics all my life,
but I couldn't have gained my
knowledge of the subatomic world

15
00:01:20,640 --> 00:01:25,760
'without the work of the chemists
who first unravelled
the mysteries of matter.'

16
00:01:25,760 --> 00:01:28,120
Brilliant.
That was really beautiful.

17
00:01:28,120 --> 00:01:31,920
Finding and understanding
the elements would turn out

18
00:01:31,920 --> 00:01:37,000
to be one of the greatest detective
stories in the history of science.

19
00:01:37,000 --> 00:01:41,320
A staggeringly difficult task
that would span centuries.

20
00:01:41,320 --> 00:01:46,360
I'm going to retrace the steps of
the chemists who risked their lives

21
00:01:46,360 --> 00:01:49,320
to prise secrets
from the natural world.

22
00:01:49,320 --> 00:01:51,920
It's instantly disfiguring,
instant blindness.

23
00:01:51,920 --> 00:01:53,800
It is really hideously dangerous.

24
00:01:53,800 --> 00:01:57,720
I'll find out
how scientists struggled

25
00:01:57,720 --> 00:02:02,320
to crack one of the most
important codes in the universe.

26
00:02:04,800 --> 00:02:11,760
And I'll discover how our
fascination with the elements led
to the making of the modern world

27
00:02:11,760 --> 00:02:16,880
and pushed the human race
to the edge of destruction.

28
00:02:16,880 --> 00:02:20,280
EXPLOSION

29
00:02:20,280 --> 00:02:24,880
Our compulsion to seek answers
at almost any cost,

30
00:02:24,880 --> 00:02:27,680
and to search
for fundamental truths,

31
00:02:27,680 --> 00:02:30,400
has powered scientific endeavour.

32
00:02:30,400 --> 00:02:33,120
And it underpins this story.

33
00:02:33,120 --> 00:02:37,920
Our quest to unravel
the mysteries of the elements.

34
00:02:53,320 --> 00:02:56,120
It's hard to imagine
what it must have been like

35
00:02:56,120 --> 00:03:00,480
to look around and not have a clue
what the world is made of.

36
00:03:00,480 --> 00:03:04,040
Not to know what this contained.

37
00:03:04,040 --> 00:03:07,480
To be mystified by fire,
to have no idea that

38
00:03:07,480 --> 00:03:12,360
oxygen is essential to make it burn
or that oxygen even existed.

39
00:03:12,360 --> 00:03:17,360
Not to know that hydrogen
is a vital ingredient of the ocean

40
00:03:17,360 --> 00:03:22,280
or that sodium and chlorine
combine to give its salty taste.

41
00:03:25,440 --> 00:03:30,120
It's only in the last 200 years
that we've known what an element is.

42
00:03:30,120 --> 00:03:35,200
It's a substance that can't be
broken down into a simpler one
by a chemical reaction.

43
00:03:37,840 --> 00:03:43,200
The ancient Greeks already knew
of lead, copper, gold, silver,

44
00:03:43,200 --> 00:03:45,840
iron, mercury, tin.

45
00:03:45,840 --> 00:03:48,640
But to them these were just metals.

46
00:03:48,640 --> 00:03:54,440
They were convinced that
the whole world was made of earth,
air, fire and water.

47
00:03:55,200 --> 00:03:58,320
For more than 1,000 years
we had no way

48
00:03:58,320 --> 00:04:01,280
of breaking open the natural world

49
00:04:01,280 --> 00:04:07,640
and no choice
but to base our concept of elements
on what was visible around us.

50
00:04:12,680 --> 00:04:16,960
By the 16th century,
things were starting to change.

51
00:04:16,960 --> 00:04:21,960
Alchemists began to penetrate
the substances around them

52
00:04:21,960 --> 00:04:25,560
in their bid
to turn base metals into gold.

53
00:04:25,560 --> 00:04:32,400
They kept secret notes of
their experiments written
in mysterious codes and symbols.

54
00:04:32,400 --> 00:04:35,680
And they dreamed of immortality.

55
00:04:35,680 --> 00:04:39,080
From the Far East,
through Europe to London,

56
00:04:39,080 --> 00:04:47,040
the backstreets and cellars
were a seething, bubbling hotbed
of alchemical research.

57
00:04:51,360 --> 00:04:55,440
It was an alchemist
who first challenged the Greek idea

58
00:04:55,440 --> 00:05:00,440
that everything was made from earth,
fire, air and water,

59
00:05:00,440 --> 00:05:04,520
in a story
which begins in Basel, Switzerland.

60
00:05:07,400 --> 00:05:12,640
It starts with Philippus
Theophrastus Aureolus Bombastus
von Hohenheim who,

61
00:05:12,640 --> 00:05:17,440
thankfully for me
because I'm not saying that again,

62
00:05:17,440 --> 00:05:20,840
adopted
the nom de plume Paracelsus.

63
00:05:23,440 --> 00:05:27,360
Paracelsus was not
just an alchemist trying to unlock

64
00:05:27,360 --> 00:05:32,040
the mysteries of matter,
he was also a physician and surgeon.

65
00:05:32,040 --> 00:05:36,560
And he wasn't afraid to challenge
the orthodoxy of the day.

66
00:05:44,360 --> 00:05:49,880
In 1526 the city of Basel
was famous for its printing.

67
00:05:49,880 --> 00:05:54,520
And its most sought after printer,
Frobenius, had just been told by

68
00:05:54,520 --> 00:06:00,520
his doctors that unless he had
his leg amputated he would die.

69
00:06:00,520 --> 00:06:04,720
So Frobenius called for Paracelsus,

70
00:06:04,720 --> 00:06:08,200
who wouldn't accept the
medical orthodoxy of the day.

71
00:06:08,200 --> 00:06:13,600
He also wasn't
afraid to mix medicine with alchemy

72
00:06:13,600 --> 00:06:17,640
to concoct
new potions and remedies.

73
00:06:17,640 --> 00:06:22,680
He created a cure that not
only saved Frobenius's life,

74
00:06:22,680 --> 00:06:26,840
but established Paracelsus
as a true radical.

75
00:06:26,840 --> 00:06:31,720
He proposed a groundbreaking new
idea, suggesting that the world

76
00:06:31,720 --> 00:06:34,520
was actually
made of three elements -

77
00:06:34,520 --> 00:06:37,760
salt, sulphur and mercury.

78
00:06:40,760 --> 00:06:47,320
Paracelsus
saw these as the core ingredients
to make metals and medicines.

79
00:06:47,320 --> 00:06:52,400
He reckoned salts would heal wounds,
sulphur was combustible

80
00:06:52,400 --> 00:06:57,360
and mercury, known then as
quicksilver, was fluid and volatile.

81
00:07:00,760 --> 00:07:03,320
Now, mercury is an
incredible substance.

82
00:07:03,320 --> 00:07:07,800
It's the only metal
that's liquid at room temperature.

83
00:07:07,800 --> 00:07:10,160
It's also remarkably heavy.

84
00:07:10,160 --> 00:07:12,960
Just this small amount here
feels very, very heavy.

85
00:07:12,960 --> 00:07:16,360
But I've got a much
larger amount here.

86
00:07:16,360 --> 00:07:19,680
And if I try and lift it...

87
00:07:22,040 --> 00:07:27,760
That's not stuck to the table,
it's 14 times heavier than water.

88
00:07:27,760 --> 00:07:32,040
It's also toxic, so I'm wearing
a triple layer of gloves here.

89
00:07:32,040 --> 00:07:35,600
Cos I'm going to do something
I've always wanted to do,

90
00:07:35,600 --> 00:07:37,800
which is dunk my hand in mercury.

91
00:07:39,000 --> 00:07:41,160
It feels very, very strange.

92
00:07:41,160 --> 00:07:43,120
It's pushing my hand up.

93
00:07:45,280 --> 00:07:49,480
It's nothing like
any liquid that I know of.

94
00:07:51,000 --> 00:07:56,120
It feels very cold as well,
even through the three layers of
gloves I can feel its coolness.

95
00:07:58,520 --> 00:08:04,640
And just to give you an idea of
how weird this stuff is,
I've got a steel bolt here.

96
00:08:04,640 --> 00:08:09,200
Let's see what happens if I put it
in the mercury.

97
00:08:09,200 --> 00:08:13,160
Mercury is so much denser
than steel. It floats.

98
00:08:19,880 --> 00:08:23,120
Mercury - silvery and mirror-like,

99
00:08:23,120 --> 00:08:28,880
it's one of the most beautiful
and elusive of all the elements.

100
00:08:28,880 --> 00:08:31,840
It's rarely
found in its natural form.

101
00:08:31,840 --> 00:08:38,680
But heating a red rock, cinnabar,
will reveal molten
mercurial lava hidden within.

102
00:08:41,600 --> 00:08:46,600
The phrase "mad as a hatter"
was coined when hat makers

103
00:08:46,600 --> 00:08:50,600
who used it
suffered from mercury madness.

104
00:08:53,040 --> 00:08:57,720
In the mines of South America,
treasure hunters risked their lives

105
00:08:57,720 --> 00:09:02,400
by using toxic mercury
to extract another element - gold.

106
00:09:03,920 --> 00:09:10,960
And floating on mercury
gave smooth motion to the revolving
light of some Victorian lighthouses.

107
00:09:15,280 --> 00:09:20,680
Paracelsus didn't manage to convince
the establishment with his idea of

108
00:09:20,680 --> 00:09:24,400
the three elements,
mercury, sulphur and salt.

109
00:09:24,400 --> 00:09:31,880
In fact, he'd enraged them
by ignoring their medical texts
and creating alchemical cures.

110
00:09:31,880 --> 00:09:34,640
He was too radical for his time.

111
00:09:34,640 --> 00:09:37,440
In a dramatic gesture

112
00:09:37,440 --> 00:09:43,120
to show his contempt for the medical
authorities, he burned their books.

113
00:09:46,560 --> 00:09:51,160
He was forced to leave Basel
University and fled to Germany,

114
00:09:51,160 --> 00:09:54,480
where he could carry on practising
medicine and alchemy.

115
00:10:01,080 --> 00:10:05,160
But he'd paved the way for a new era
of questioning,

116
00:10:05,160 --> 00:10:08,800
at a time when many alchemists
were more interested in making gold.

117
00:10:08,800 --> 00:10:13,320
They would heat metals
in scorching furnaces.

118
00:10:13,320 --> 00:10:15,680
They'd boil, they'd distill.

119
00:10:16,920 --> 00:10:21,600
And it was the pursuit of gold that
lead to the first major breakthrough

120
00:10:21,600 --> 00:10:24,680
in the hunt to discover elements.

121
00:10:26,200 --> 00:10:30,160
For the alchemists,
gold was like the holy grail.

122
00:10:30,160 --> 00:10:35,640
They believed
it possessed spiritual, magical,
even medical properties.

123
00:10:35,640 --> 00:10:38,640
It was the stuff of power,
the colour of the sun.

124
00:10:38,640 --> 00:10:41,680
It was made into crowns and coins.

125
00:10:41,680 --> 00:10:46,600
It adorned kings, queens,
palaces and temples
for over thousands of years.

126
00:10:50,480 --> 00:10:56,000
In ancient Egypt, gold was
thought to be the skin of the gods.

127
00:10:57,680 --> 00:11:02,800
To the Inca civilisation,
gold was the sweat of the sun.

128
00:11:05,760 --> 00:11:10,720
The alchemists
didn't yet know what an element was.

129
00:11:10,720 --> 00:11:16,640
But some unwittingly
touched on the idea that they could
be hidden within other substances

130
00:11:16,640 --> 00:11:21,760
when they suggested that gold might
be concealed within the human body.

131
00:11:25,640 --> 00:11:30,240
The relentless pursuit of
this obsession led one alchemist

132
00:11:30,240 --> 00:11:35,520
to become the first person credited
with the discovery of a new element.

133
00:11:35,520 --> 00:11:37,320
Hennig Brand.

134
00:11:39,680 --> 00:11:43,920
He was searching for a way of
extracting gold from the body

135
00:11:43,920 --> 00:11:47,600
when he hit upon
what seemed like a smart idea,

136
00:11:47,600 --> 00:11:53,760
a gold coloured liquid
in plentiful supply - urine.

137
00:11:56,760 --> 00:12:04,480
It was 1669 and in the dark,
smelly basement of his
Hamburg House, Brand's expensive

138
00:12:04,480 --> 00:12:10,720
alchemical experiments were
rapidly eating through the funds
of his wealthy wife, Margeretha.

139
00:12:10,720 --> 00:12:18,080
But now, with his urine brainwave,
Brand believed that he was on the
threshold of a momentous discovery.

140
00:12:18,080 --> 00:12:21,480
He was about to make his name
and restore his family fortune.

141
00:12:21,480 --> 00:12:25,040
All he needed was another
fifty buckets of urine.

142
00:12:27,880 --> 00:12:32,360
'Chemist Dr Andrea Sella
has been studying Brand's work

143
00:12:32,360 --> 00:12:36,200
'and is going to attempt to
find the hidden element.'

144
00:12:36,200 --> 00:12:38,240
If you pass me the urine.

145
00:12:38,240 --> 00:12:42,480
You're welcome.
And this is courtesy of myself.

146
00:12:42,480 --> 00:12:45,280
I'm already holding my breath.

147
00:12:45,280 --> 00:12:48,880
Ahh, you know,
you know you mustn't over-react.

148
00:12:48,880 --> 00:12:51,040
So what would Brand have done?

149
00:12:51,040 --> 00:12:54,160
What Brand was trying to do was
to get to the heart of the matter.

150
00:12:54,160 --> 00:12:58,920
To start boiling it down,
to get rid of the unimportant parts.

151
00:12:58,920 --> 00:13:01,760
That, of course,
was principally the water.

152
00:13:01,760 --> 00:13:05,320
There is an additional feature
and it's not really surprising.

153
00:13:05,320 --> 00:13:08,720
But, you know,
have a quick waft of that.

154
00:13:08,720 --> 00:13:11,360
Yeah, it's pretty bad.

155
00:13:12,880 --> 00:13:15,960
Brand must have had some very,
very patient neighbours.

156
00:13:15,960 --> 00:13:21,680
I really don't know what his romantic
life must have been like, but I can't
imagine he was all that popular.

157
00:13:22,840 --> 00:13:26,960
You see, I can understand
urine being gold coloured.

158
00:13:26,960 --> 00:13:30,240
But Brand was looking to make gold.
What is the connection?

159
00:13:30,240 --> 00:13:36,960
First of all it seems tremendously
laughable to us to use something as
disgusting a waste product as urine.

160
00:13:36,960 --> 00:13:41,880
One of the alchemical views
was that man was really a microcosm
of the universe and, therefore,

161
00:13:41,880 --> 00:13:47,680
urine actually carried within it some
of that vital force. The life force.

162
00:13:47,680 --> 00:13:51,000
So a sort of metaphysical
symbol of life?

163
00:13:51,000 --> 00:13:55,080
Absolutely. And so, really,
this was a substance of power.

164
00:13:55,080 --> 00:14:00,200
Brand was determined to
persevere with his quest for gold.

165
00:14:00,200 --> 00:14:02,480
He distilled the
urine down to a paste,

166
00:14:02,480 --> 00:14:07,920
then heated it at a phenomenal
temperature for several days.

167
00:14:07,920 --> 00:14:13,800
Eventually,
wisps of smoke revealed tiny
fragments that combusted in air.

168
00:14:13,800 --> 00:14:17,080
But what was this fiery substance?

169
00:14:17,080 --> 00:14:22,600
It wasn't golden like the sun,
but it burned brighter
than any medieval candle.

170
00:14:35,920 --> 00:14:40,720
So this is what
Brand isolated from urine.

171
00:14:40,720 --> 00:14:42,400
It's not gold.

172
00:14:42,400 --> 00:14:45,200
This is phosphorus.

173
00:14:45,200 --> 00:14:53,160
Brand had discovered,
completely by accident,
a new element, never seen by man.

174
00:14:53,160 --> 00:14:56,080
Fiery phosphorus.

175
00:14:57,560 --> 00:15:00,760
He was looking for riches
but didn't realise that he'd

176
00:15:00,760 --> 00:15:08,440
unearthed a fundamental notion,
that elements could be
concealed within a hidden world.

177
00:15:08,440 --> 00:15:11,280
Phosphorus is biologically
very, very important.

178
00:15:11,280 --> 00:15:15,640
If you think of our bones
they're composed predominantly
of calcium hydroxy phosphates.

179
00:15:15,640 --> 00:15:17,560
There's lots of phosphate there.

180
00:15:17,560 --> 00:15:21,360
It's in our DNA,
it's in all sorts of our tissues, and

181
00:15:21,360 --> 00:15:26,680
as a result there's always phosphate
in the blood and some of it, excess,
is transferred into the urine.

182
00:15:26,680 --> 00:15:29,640
A little bit less than
about a gram per litre.

183
00:15:29,640 --> 00:15:31,720
This stuff is a complete tiger.

184
00:15:31,720 --> 00:15:37,080
You can see that it starts to smoke
very gently in air.

185
00:15:37,080 --> 00:15:42,800
And this is really a warning to us
that things are going to happen
if we don't deal with it quickly.

186
00:15:42,800 --> 00:15:46,080
So we're going to drop
it into this flask.

187
00:15:46,080 --> 00:15:48,440
The flask is actually
filled with oxygen.

188
00:15:48,440 --> 00:15:50,760
And so it's sitting in sand

189
00:15:50,760 --> 00:15:55,000
just to keep the heat
from attacking the glass.

190
00:15:55,000 --> 00:15:58,160
And now I'm going to touch
it with a hot glass rod.

191
00:16:07,280 --> 00:16:09,480
And so there it is.

192
00:16:09,480 --> 00:16:11,680
That's fantastic

193
00:16:11,680 --> 00:16:14,720
and it sort of feels cold.
It's not hot.

194
00:16:14,720 --> 00:16:17,080
That's quite beautiful.

195
00:16:17,080 --> 00:16:19,520
Because it shone so vividly,

196
00:16:19,520 --> 00:16:25,960
yet was cold enough to hold,
Brand called his
discovery "Icy Nocta Luca."

197
00:16:25,960 --> 00:16:28,560
Cold night light.

198
00:16:31,560 --> 00:16:36,400
Phosphorus. It's in
every cell in the human body.

199
00:16:36,400 --> 00:16:42,720
It's used in drugs to
promote bone growth,
treating diseases like osteoporosis.

200
00:16:43,840 --> 00:16:49,400
153 million tonnes of phosphorus
are produced every year.

201
00:16:49,400 --> 00:16:56,320
Its phosphate is consumed
as a food supplement,
and is an ingredient of toothpaste.

202
00:16:56,320 --> 00:16:59,920
But eating just 100 milligrams
of pure phosphorous,

203
00:16:59,920 --> 00:17:03,520
enough to coat a finger tip,
could be fatal.

204
00:17:04,520 --> 00:17:07,720
And it has an even darker side.

205
00:17:07,720 --> 00:17:15,280
In the Second World War, phosphorus
was used in the thousands
of bombs dropped on Hamburg.

206
00:17:15,280 --> 00:17:18,360
The city where Brand discovered it.

207
00:17:27,800 --> 00:17:32,000
Brand hoped that phosphorus would
make him a fortune,

208
00:17:32,000 --> 00:17:37,360
but his cash ran out
and he sold the secret of his
discovery for a paltry sum.

209
00:17:38,880 --> 00:17:43,160
Before long
phosphorous was being touted round
the royal courts of Europe.

210
00:17:44,680 --> 00:17:49,760
And in 1677 it arrived
at the court of King Charles II.

211
00:17:49,760 --> 00:17:55,360
Soon after, wealthy alchemist Robert
Boyle, witnessed its luminous magic

212
00:17:55,360 --> 00:17:59,240
and determined
to investigate its properties.

213
00:17:59,240 --> 00:18:05,040
Dr Andrea Sella and I are going to
follow Boyle's own instructions

214
00:18:05,040 --> 00:18:09,040
to attempt one of his
most significant
experiments on phosphorus.

215
00:18:09,040 --> 00:18:12,800
So I have here extracts
from Robert Boyle's book,

216
00:18:12,800 --> 00:18:17,400
New Experiments and Observations
Made Upon the Icy Nocte Luca.

217
00:18:17,400 --> 00:18:21,720
Having put together about half a
grain of our dry nocte luca matter.

218
00:18:21,720 --> 00:18:23,640
How much is half a grain?

219
00:18:23,640 --> 00:18:25,880
Well, half a grain
really isn't very much.

220
00:18:25,880 --> 00:18:29,160
There's 7000 grains to the pound.

221
00:18:29,160 --> 00:18:31,040
So you can work it out.

222
00:18:31,040 --> 00:18:32,680
You're the physicist.

223
00:18:32,680 --> 00:18:37,440
OK, and six times its weight
of common flowers of sulphur.

224
00:18:37,440 --> 00:18:40,080
OK, so we'll
just put a little piece...

225
00:18:40,080 --> 00:18:45,120
So that's just sulphur powder,
is it? Yes, it's
essentially finely powdered sulphur.

226
00:18:45,120 --> 00:18:49,400
Right and it says,
they were lodged in the fold of
a piece of white paper.

227
00:18:49,400 --> 00:18:51,960
He rubbed it
with the haft of a knife.

228
00:18:51,960 --> 00:18:55,360
Well, I haven't got a knife
but I do have a spatula.

229
00:18:55,360 --> 00:18:58,720
That'll do. So we'll use that.
OK. It's beginning to smoke. OK.

230
00:18:58,720 --> 00:19:02,080
It's beginning to kindle. We've got
a little bit of fire there already.

231
00:19:02,080 --> 00:19:03,840
The main lump of phosphorus...

232
00:19:03,840 --> 00:19:06,920
Oh, look there it goes. Oh,
there it goes. There it goes. Whoa!

233
00:19:08,200 --> 00:19:11,200
Didn't have time to bruise it.
It didn't need bruising. It went up.

234
00:19:11,200 --> 00:19:15,080
So you've basically recreated
what is the precursor to the match.

235
00:19:15,080 --> 00:19:19,240
Yes, and I've also got some
splendid smoke rings here.

236
00:19:20,760 --> 00:19:25,920
I mean this would really
radically transform things because
what you had was fire on demand.

237
00:19:25,920 --> 00:19:30,880
Boyle had stumbled upon the
essential ingredient of a match.

238
00:19:32,880 --> 00:19:36,960
A huge industry was spawned
from this single experiment.

239
00:19:36,960 --> 00:19:41,560
But Boyle wasn't really
interested in the money making
potential of phosphorus,

240
00:19:41,560 --> 00:19:44,640
just understanding the properties
of this element

241
00:19:44,640 --> 00:19:46,360
was reward enough for him.

242
00:19:58,680 --> 00:20:02,840
So phosphorus did have
transformational powers after all.

243
00:20:04,200 --> 00:20:12,160
It may not have changed lead into
gold, but it turned an alchemist
into the first modern chemist.

244
00:20:12,160 --> 00:20:16,360
Boyle had set the stage
for future element hunters.

245
00:20:16,360 --> 00:20:19,680
Unlike most alchemists,
he shared his methods

246
00:20:19,680 --> 00:20:25,680
and was able to pass on the tools
they needed to help
unlock the mysteries of matter.

247
00:20:28,320 --> 00:20:33,360
I've come to search the vaults
of the Royal Society in London.

248
00:20:33,360 --> 00:20:40,960
What I am looking for was deposited
here in 1661, just one year
after the Society was formed.

249
00:20:44,520 --> 00:20:46,360
Here it is.

250
00:20:46,360 --> 00:20:48,720
The Sceptical Chemist.

251
00:20:48,720 --> 00:20:54,440
It was written by Robert Boyle,
who was one of the founders
of the Royal Society.

252
00:20:55,440 --> 00:21:01,880
Dr Anna Marie Roos, a specialist
in the history of chemistry,
has studied Boyle's writings.

253
00:21:01,880 --> 00:21:04,960
I've got a copy of Boyle's,
Sceptical Chemist.

254
00:21:04,960 --> 00:21:06,840
Why was this book so important?

255
00:21:06,840 --> 00:21:10,560
This was really considered to be one
of one of the books

256
00:21:10,560 --> 00:21:14,400
that signifies a transition
from alchemy to chemistry

257
00:21:14,400 --> 00:21:17,680
and some scholars have thought
it's the first book of chemistry.

258
00:21:17,680 --> 00:21:22,680
The fact that book was written
in plain English
was also quite a new thing.

259
00:21:22,680 --> 00:21:28,200
'You only have to
compare Boyle's book to the cryptic
writings of another alchemist.'

260
00:21:28,200 --> 00:21:33,080
That great man of science,
Isaac Newton,
to appreciate its innovation.

261
00:21:33,080 --> 00:21:37,600
And we can see here that it's in
Latin and we also can see that

262
00:21:37,600 --> 00:21:42,560
there are several alchemical symbols
being used for the chemical elements.

263
00:21:42,560 --> 00:21:46,040
It really does remind me
of astrology

264
00:21:46,040 --> 00:21:48,560
and Egyptian hieroglyphics.
Absolutely.

265
00:21:48,560 --> 00:21:54,360
And I compare that with Boyle
where he says things like,
"He took 200 pounds of earth,

266
00:21:54,360 --> 00:21:58,240
"dried in an oven, having put it
in an earthen vessel and melted it."

267
00:21:58,240 --> 00:22:01,200
He's describing a chemical process.

268
00:22:01,200 --> 00:22:05,920
Absolutely. What made Boyle a bit
different is that he was willing to

269
00:22:05,920 --> 00:22:11,120
divulge some of his chemical
secrets for the good of
the scientific community.

270
00:22:14,280 --> 00:22:21,640
Boyle was bringing alchemy
out of the shadows and
into an enlightened, rational age.

271
00:22:21,640 --> 00:22:25,480
He was opening up the scientific
method for everyone to see.

272
00:22:25,480 --> 00:22:29,400
The alchemists must have feared
he was giving away their secrets.

273
00:22:29,400 --> 00:22:32,360
But he wasn't so much interested
in debunking alchemy,

274
00:22:32,360 --> 00:22:35,600
as getting
rid of its metaphysical baggage

275
00:22:35,600 --> 00:22:39,760
and replacing it with a more
rigorous scientific approach.

276
00:22:43,880 --> 00:22:49,000
A new age of scientific
experimentation had begun.

277
00:22:55,400 --> 00:23:00,480
And with a more open exchange of
ideas came a rejection of tradition.

278
00:23:00,480 --> 00:23:04,360
It heralded an era
in which the ancient Greek doctrines

279
00:23:04,360 --> 00:23:08,800
were re-evaluated
and new concepts introduced.

280
00:23:10,640 --> 00:23:16,920
Copernicus challenged the ancient
idea that the Earth was
at the centre of the universe,

281
00:23:16,920 --> 00:23:22,200
proposing instead that it
was just one of a number of
planets orbiting around the sun.

282
00:23:22,200 --> 00:23:25,800
Vesalius mapped the human body.

283
00:23:25,800 --> 00:23:29,840
It was an exciting and liberating
time in which Europe was being

284
00:23:29,840 --> 00:23:34,120
dragged out of its dark ages
and into an age of reason.

285
00:23:38,680 --> 00:23:41,800
But just because people were
thinking differently,

286
00:23:41,800 --> 00:23:45,000
didn't necessarily mean that
they were getting it right.

287
00:23:45,000 --> 00:23:50,680
And while a new generation of
scientists were keen to come up
with modern elements to replace the

288
00:23:50,680 --> 00:23:57,920
four ancient ones, their enthusiasm
didn't stop them from buying
into completely false theories.

289
00:23:57,920 --> 00:24:04,160
And so it was that science went up
one of the greatest blind alleys
in the history of chemistry.

290
00:24:06,440 --> 00:24:11,120
It was 1667, a year after
the Great Fire of London

291
00:24:11,120 --> 00:24:14,760
had razed one of Europe's
greatest cities to the ground.

292
00:24:16,520 --> 00:24:21,360
The mysteries of fire were at the
forefront of everyone's minds.

293
00:24:21,360 --> 00:24:25,960
But no-one really understood what
fire was or how it was created.

294
00:24:27,680 --> 00:24:31,880
German chemist, Johann Becher,
proposed that the destructive

295
00:24:31,880 --> 00:24:37,720
power of fire was caused by an
ethereal entity named phlogiston.

296
00:24:37,720 --> 00:24:41,480
It was thought to be
an odourless, colourless,

297
00:24:41,480 --> 00:24:48,880
tasteless and weightless substance,
that causes things to burn,
reducing them to their true form.

298
00:24:48,880 --> 00:24:52,840
This burning wood produces ash.

299
00:24:52,840 --> 00:24:58,400
So wood must be made up
of ash, pure wood, plus phlogiston.

300
00:25:00,360 --> 00:25:05,360
The notion of phlogiston seemed so
credible in the 17th century

301
00:25:05,360 --> 00:25:08,880
that it
consumed the scientific community.

302
00:25:08,880 --> 00:25:12,880
It was accepted as a truth,
virtually paralysing our ability

303
00:25:12,880 --> 00:25:17,960
to discover more elements and map
the contours of the natural world.

304
00:25:17,960 --> 00:25:24,080
One great chemist who
experimented with gases
even claimed to have isolated it.

305
00:25:25,600 --> 00:25:29,480
On the same day every week for
50 years

306
00:25:29,480 --> 00:25:35,200
a rather peculiar scientist came to
the Royal Society Dinner Club

307
00:25:35,200 --> 00:25:38,240
to discuss the
latest scientific ideas.

308
00:25:43,080 --> 00:25:50,480
Henry Cavendish has been described
as "the richest of the learned,
and the most learned of the rich".

309
00:25:50,480 --> 00:25:56,200
He was a major shareholder
in the Bank of England,
and had royal connections.

310
00:25:56,200 --> 00:26:01,280
But it's remarkable he came
to a social gathering at all.

311
00:26:01,280 --> 00:26:06,200
Cavendish was painfully shy
and lived in virtual isolation.

312
00:26:06,200 --> 00:26:11,560
At home,
he insisted that his servants only
communicate with him in writing.

313
00:26:11,560 --> 00:26:15,600
Colleagues at the Dinner Club said
that he'd often be found outside,

314
00:26:15,600 --> 00:26:17,760
trying to pluck up
the courage to go in.

315
00:26:17,760 --> 00:26:25,000
And when speaking to him it was best
to look into the air with vacancy
rather than directly at him.

316
00:26:25,000 --> 00:26:28,920
Despite signs of what we might
recognise today as autism,

317
00:26:28,920 --> 00:26:33,440
Cavendish made a vital contribution
to the discovery of the elements.

318
00:26:36,640 --> 00:26:40,920
I'm going to investigate how
Cavendish's experiments with airs

319
00:26:40,920 --> 00:26:45,400
led him to find the first element
that's a gas.

320
00:26:49,760 --> 00:26:55,720
Cavendish added a metal,
zinc, to an acid.

321
00:26:55,720 --> 00:26:57,680
It was deceptively simple.

322
00:26:57,680 --> 00:27:00,000
And pretty soon...

323
00:27:00,000 --> 00:27:04,440
bubbles began to appear
on the surface of the zinc.

324
00:27:04,440 --> 00:27:11,080
Cavendish started to collect
this gas, which I'm going to do
in this test tube.

325
00:27:11,080 --> 00:27:16,640
It didn't smell of anything,
it didn't taste of anything,
in fact it was completely invisible.

326
00:27:16,640 --> 00:27:21,040
Cavendish soon realised
this was no ordinary gas.

327
00:27:21,040 --> 00:27:23,280
And then...

328
00:27:23,280 --> 00:27:25,680
he set light to it.

329
00:27:27,200 --> 00:27:28,600
POP

330
00:27:29,600 --> 00:27:33,120
Cavendish had no idea
he'd discovered a new element,

331
00:27:33,120 --> 00:27:38,320
in fact he thought he'd found
a new kind of air,
different to the air we breath.

332
00:27:38,320 --> 00:27:42,400
He called it, not surprisingly,
"inflammable air".

333
00:27:42,400 --> 00:27:48,480
And he believed his inflammable air
had to be the mysterious phlogiston.

334
00:27:50,080 --> 00:27:56,560
It was, odourless,
tasteless, colourless and
most importantly, it caught fire.

335
00:27:56,560 --> 00:27:58,960
It HAD to be phlogiston.

336
00:27:58,960 --> 00:28:01,120
But he was wrong.

337
00:28:01,120 --> 00:28:07,120
Cavendish didn't realise it but he'd
isolated a new element, hydrogen.

338
00:28:08,320 --> 00:28:12,280
He investigated the
characteristics of his new air and

339
00:28:12,280 --> 00:28:17,480
calculated that it was eleven times
lighter than the air we breathe.

340
00:28:18,480 --> 00:28:21,400
Now, I've got Asma here to help me.

341
00:28:21,400 --> 00:28:25,720
She's pumping hydrogen
through into this washing up liquid

342
00:28:25,720 --> 00:28:29,040
and creating bubbles of hydrogen
coming up through this funnel.

343
00:28:29,040 --> 00:28:31,240
Because hydrogen is so
much lighter than air,

344
00:28:31,240 --> 00:28:34,800
at some point these bubbles will
separate and start to float up.

345
00:28:38,400 --> 00:28:41,160
Brilliant,
that was really beautiful.

346
00:28:42,680 --> 00:28:46,600
'It was lighter than air
and burst into flames.

347
00:28:46,600 --> 00:28:49,840
'You can see why Cavendish
thought it was phlogiston.'

348
00:28:49,840 --> 00:28:52,240
Cor, they're getting better!

349
00:28:53,280 --> 00:29:00,880
But this belief meant Cavendish
wasn't credited with the discovery
of hydrogen during his lifetime.

350
00:29:02,720 --> 00:29:06,480
Nor would he witness its full force.

351
00:29:11,600 --> 00:29:16,840
Hydrogen -
produced just after the Big Bang
alongside helium and lithium,

352
00:29:16,840 --> 00:29:21,640
it's the most abundant and
lightest element in the universe.

353
00:29:23,520 --> 00:29:29,040
The suns energy comes from
the nuclear fusion of hydrogen.

354
00:29:29,040 --> 00:29:33,760
The same principle
harnessed in the hydrogen bomb.

355
00:29:37,320 --> 00:29:41,400
Hydrogen's highly flammable nature
was witnessed

356
00:29:41,400 --> 00:29:48,440
when it ignited the
Hindenburg zeppelin airship in 1937,
killing 36 people.

357
00:30:01,760 --> 00:30:08,200
'Like so many other element hunters,
Cavendish didn't realise the
significance of his discovery.

358
00:30:08,200 --> 00:30:13,960
'But he did observe something that
would play a crucial role in our
understanding of the natural world.'

359
00:30:17,040 --> 00:30:20,760
Each time he set light to the gas,

360
00:30:20,760 --> 00:30:25,960
a dewy liquid began to appear
on the surface of the glass.

361
00:30:25,960 --> 00:30:28,280
It was water.

362
00:30:28,280 --> 00:30:32,440
Now this had incredible implications
back in the 1700's because back then

363
00:30:32,440 --> 00:30:37,280
they believed in the ancient Greek
idea that water was an element.

364
00:30:37,280 --> 00:30:41,400
But if you can make water
out of two other constituents,

365
00:30:41,400 --> 00:30:47,720
then it couldn't be an element.
In fact, water is a compound.

366
00:30:54,640 --> 00:31:01,320
'This struck right to the heart
of the ancient concept
of four elements.

367
00:31:01,320 --> 00:31:06,800
'Cavendish's observations
could have shaken the foundations
of accepted belief.

368
00:31:06,800 --> 00:31:12,520
'But they didn't, because he was
thrown off-course by phlogiston.

369
00:31:12,520 --> 00:31:17,120
'He reckoned that the airs
must contain a form of water

370
00:31:17,120 --> 00:31:20,080
'modified by the presence
of phlogiston.

371
00:31:20,080 --> 00:31:26,760
'It simply didn't occur to him
that water was a compound.'

372
00:31:26,760 --> 00:31:31,400
So while he was very close to
destroying the temple
of the ancient four elements,

373
00:31:31,400 --> 00:31:34,960
he couldn't quite yet
disprove them.

374
00:31:34,960 --> 00:31:39,480
The pillars of that temple were
now standing on very shaky ground,

375
00:31:39,480 --> 00:31:43,120
and it wouldn't be too long
before they'd come crashing down.

376
00:31:43,120 --> 00:31:48,080
But it wasn't Cavendish's water
that would finally disprove
the ancient theory.

377
00:31:48,080 --> 00:31:50,280
It was air.

378
00:31:55,880 --> 00:32:01,600
'19 of what we now call elements
had been found so far,

379
00:32:01,600 --> 00:32:05,920
'but 18th-century scientists were
still grappling to work out

380
00:32:05,920 --> 00:32:07,880
'what the world was made of.'

381
00:32:09,600 --> 00:32:13,200
'The Royal Society
had commissioned its members

382
00:32:13,200 --> 00:32:15,960
'to investigate
the invisible airs.'

383
00:32:19,680 --> 00:32:26,600
By the mid-1700s, there were
three known types of air, or gases.

384
00:32:26,600 --> 00:32:30,240
There was the common air,
that we breathe, inflammable air,

385
00:32:30,240 --> 00:32:35,240
now known as hydrogen,
and fixed air, or carbon dioxide.

386
00:32:35,240 --> 00:32:40,000
And experimenting with these airs
was a favourite pastime

387
00:32:40,000 --> 00:32:45,360
of clergyman and amateur chemist
Joseph Priestley.

388
00:32:45,360 --> 00:32:51,920
'Priestley lived next to a brewery,
and spent rather a lot of time
there, especially considering

389
00:32:51,920 --> 00:32:57,040
'he was a Unitarian minister,
known for his extreme sermons.'

390
00:32:59,040 --> 00:33:01,880
But he wasn't here for the beer.

391
00:33:01,880 --> 00:33:07,200
Priestley was interested in the gas
that's produced
in the fermentation process.

392
00:33:07,200 --> 00:33:14,000
He called it brewery gas,
but of course it was well known
by that time as fixed air.

393
00:33:14,000 --> 00:33:17,760
We know it today as carbon dioxide.

394
00:33:17,760 --> 00:33:20,840
Carbon dioxide is being produced
inside this vat,

395
00:33:20,840 --> 00:33:25,680
and because it's heavier than air,
it's pouring out and cascading down.

396
00:33:25,680 --> 00:33:29,960
Now we can't see it, but
an experiment that Priestley himself

397
00:33:29,960 --> 00:33:36,200
carried out involved seeing what
carbon dioxide does to a lit flame.

398
00:33:36,200 --> 00:33:40,880
So if I hold this flame here,

399
00:33:40,880 --> 00:33:44,560
it's not in the path of the gas
at the moment,
but if I bring it down...

400
00:33:46,360 --> 00:33:48,680
You can see it immediately
extinguishes.

401
00:33:48,680 --> 00:33:52,160
You can even see the trail of smoke
following the path of the gas.

402
00:33:54,920 --> 00:33:58,280
'Priestley
was fascinated by fixed air.

403
00:33:58,280 --> 00:34:03,760
'He mixed it with water, and so
invented the first fizzy drink.

404
00:34:03,760 --> 00:34:07,640
'In time it would spawn an industry
worth millions,

405
00:34:07,640 --> 00:34:10,560
'but he earned
almost nothing from it.

406
00:34:10,560 --> 00:34:13,840
'Instead,
Priestley's passion for science

407
00:34:13,840 --> 00:34:17,240
'led to an invitation to
Bowood House in Wiltshire,

408
00:34:17,240 --> 00:34:22,960
'to tutor the children of the future
Prime Minister, Lord Shelburne.'

409
00:34:23,960 --> 00:34:29,480
Priestley lacked the wealth
of earlier chemists
like Boyle and Cavendish.

410
00:34:29,480 --> 00:34:34,400
And he made little money from his
inventions and his radical writings.

411
00:34:34,400 --> 00:34:37,520
Lord Shelburne was offering him
financial stability

412
00:34:37,520 --> 00:34:43,120
and the chance to continue
with his scientific experiments,
in return for teaching.

413
00:34:43,120 --> 00:34:46,960
He became the first professional,
salaried chemist.

414
00:34:46,960 --> 00:34:51,840
And it was here that he continued
his experiments with airs.

415
00:34:56,000 --> 00:35:00,360
On 1st August 1774, he performed

416
00:35:00,360 --> 00:35:04,120
one of the most important
experiments in chemical history.

417
00:35:05,640 --> 00:35:11,160
'Priestley was gripped by unlocking
the elemental secrets of the airs.

418
00:35:11,160 --> 00:35:16,600
'On this occasion he started with
a powder he knew as mercuric calx.

419
00:35:16,600 --> 00:35:18,960
'Mercuric oxide.

420
00:35:18,960 --> 00:35:23,960
'He put it in a test tube to collect
any gas it might give off
when he heated it.'

421
00:35:26,000 --> 00:35:30,760
'Then he filled the test tube with
mercury, which would trap the gas.'

422
00:35:30,760 --> 00:35:34,600
So I now place my finger
over the top of the tube,

423
00:35:34,600 --> 00:35:39,440
invert it, so that it's submerged
into the mercury bath.

424
00:35:39,440 --> 00:35:45,360
I now have the mercuric oxide powder
at the very top of the tube.

425
00:35:45,360 --> 00:35:49,120
What Priestley did next
was heat up this powder.

426
00:35:51,640 --> 00:35:55,040
The level of the mercury
in the tube is dropping.

427
00:35:56,560 --> 00:36:01,400
What's going on is a gas
is being produced that is
pushing the mercury down.

428
00:36:01,400 --> 00:36:04,920
What in fact is happening is that
this mercuric oxide powder

429
00:36:04,920 --> 00:36:08,360
is being broken up
into its two components.

430
00:36:09,880 --> 00:36:14,280
I'm now going to see what gas
Priestley had made.

431
00:36:14,280 --> 00:36:21,040
If I take this splint and blow it
out so I just have a glowing ember,

432
00:36:21,040 --> 00:36:23,080
it bursts back into flame again.

433
00:36:23,080 --> 00:36:28,120
'We now know that Joseph Priestley
had found oxygen.

434
00:36:28,120 --> 00:36:33,080
'But because he believed in the idea
of phlogiston, he thought the splint

435
00:36:33,080 --> 00:36:37,800
'was introducing phlogiston
to the new air and catching fire.

436
00:36:37,800 --> 00:36:42,840
'He concluded that his air
must be without phlogiston.

437
00:36:42,840 --> 00:36:47,320
'So he called it
dephlogisticated air.'

438
00:36:47,320 --> 00:36:51,520
Priestley's experiments with
his new air didn't stop there.

439
00:36:51,520 --> 00:36:53,880
In fact, they got stranger.

440
00:36:53,880 --> 00:36:58,760
He placed a mouse inside a sealed
container filled with this new air,

441
00:36:58,760 --> 00:37:01,320
expecting it to live for
just 15 minutes.

442
00:37:01,320 --> 00:37:06,080
Instead, he found it alive and well
after half an hour.

443
00:37:06,080 --> 00:37:09,640
He then tried breathing it himself
and noted...

444
00:37:09,640 --> 00:37:16,040
"I fancy my breast felt particularly
light and easy after some time.

445
00:37:16,040 --> 00:37:19,720
"Who can tell but that, in time,
this pure air

446
00:37:19,720 --> 00:37:23,400
"may become a fashionable article
of luxury.

447
00:37:23,400 --> 00:37:28,760
"Hitherto only two mice and I have
had the privilege of breathing it."

448
00:37:29,840 --> 00:37:36,000
'Little did Priestley know
that everyone had had the privilege
of breathing it.'

449
00:37:38,760 --> 00:37:43,760
'Oxygen is the third most abundant
element in the universe

450
00:37:43,760 --> 00:37:48,040
'and makes up over half the weight
of a human body.

451
00:37:48,040 --> 00:37:55,200
'At minus 183 degrees Celsius,
it condenses to a pale blue liquid.

452
00:37:55,200 --> 00:38:01,160
'Steel smelting
uses more than half of the world's
commercially produced oxygen.

453
00:38:01,160 --> 00:38:04,400
'It's also used in rocket fuel.'

454
00:38:06,080 --> 00:38:10,160
'Around 21% of air is oxygen.

455
00:38:10,160 --> 00:38:13,080
'A few percent less
and we couldn't breathe.

456
00:38:13,080 --> 00:38:17,440
'A few percent more
and any organic matter ignited

457
00:38:17,440 --> 00:38:20,520
'would burn out of control.'

458
00:38:26,600 --> 00:38:30,640
'Although Priestley knew
he'd found something special,

459
00:38:30,640 --> 00:38:33,880
'he didn't realise
he'd isolated an element.'

460
00:38:35,840 --> 00:38:39,480
'He was still hampered
by his belief in phlogiston.

461
00:38:39,480 --> 00:38:43,320
'But his path was about to cross
with a visionary

462
00:38:43,320 --> 00:38:46,880
'who was also
thinking about gases and airs.'

463
00:38:51,600 --> 00:38:55,400
In October 1774,
Priestley accompanied

464
00:38:55,400 --> 00:39:00,560
his benefactor Lord Shelburne
on a Grand Tour of Europe.

465
00:39:05,560 --> 00:39:09,320
They headed to Paris,
where they were invited to

466
00:39:09,320 --> 00:39:12,760
dine with some of the country's
most pre-eminent scientists.

467
00:39:12,760 --> 00:39:17,680
It must have been quite an occasion
for a down-to-earth
Yorkshireman like Priestley.

468
00:39:17,680 --> 00:39:22,800
One of the guests was the stellar
French scientist Antoine Laviosier.

469
00:39:22,800 --> 00:39:28,960
By the age of 28
he had already been elected
to the French Academy of Sciences.

470
00:39:28,960 --> 00:39:34,080
This guy was incredible.
He'd published everything from
the mineralogy of the Pyrenees

471
00:39:34,080 --> 00:39:38,960
through to locating the best sites
for abattoirs in Paris.

472
00:39:45,720 --> 00:39:50,240
'Lavoisier was not only a member of
a newly emerging scientific elite,

473
00:39:50,240 --> 00:39:56,240
'but a tax collector
and an extremely wealthy
member of the bourgeoisie.

474
00:39:56,240 --> 00:40:01,920
'And he was determined to crack open
the mysteries of the natural world.'

475
00:40:02,920 --> 00:40:07,720
When Lavoisier and Priestley met
over dinner, they talked chemistry.

476
00:40:07,720 --> 00:40:15,240
And conversation soon turned to
Priestley's exciting new discovery
of dephlogisticated air.

477
00:40:15,240 --> 00:40:18,880
Lavoisier, intrigued,
pressed him for details,

478
00:40:18,880 --> 00:40:23,320
and Priestley clearly found him
a very attentive listener

479
00:40:23,320 --> 00:40:26,840
because he told him
all about his experiment.

480
00:40:29,840 --> 00:40:34,080
'Lavoisier and Priestley
were like chalk and cheese.'

481
00:40:34,080 --> 00:40:38,520
Lavoisier had the best-equipped
laboratory in Europe,

482
00:40:38,520 --> 00:40:44,440
with more than 10,000 pieces
of precision technology.

483
00:40:44,440 --> 00:40:47,000
Priestley worked in a makeshift lab

484
00:40:47,000 --> 00:40:50,560
with equipment
he'd just cobbled together.

485
00:40:50,560 --> 00:40:56,160
Lavoisier weighed, measured,
re-weighed and calculated precisely

486
00:40:56,160 --> 00:40:58,960
before and after every reaction.

487
00:40:58,960 --> 00:41:05,960
And he applied this approach
to investigate the great mystery
of phlogiston.

488
00:41:05,960 --> 00:41:12,000
Lavoisier's breakthrough came
when he turned his fanatical
attention to detail

489
00:41:12,000 --> 00:41:16,680
to the weight of substances
before and after they were heated.

490
00:41:16,680 --> 00:41:21,720
He first weighed a metal
very precisely - in this case, tin.

491
00:41:25,280 --> 00:41:30,280
And if I check the reading,
it's 150.07 grams.

492
00:41:30,280 --> 00:41:34,280
'Heating tin and then reweighing it

493
00:41:34,280 --> 00:41:38,120
'revealed a nagging problem
with the theory of phlogiston.

494
00:41:38,120 --> 00:41:42,960
'If phlogiston is given off
when a substance is heated,
it should weigh less.'

495
00:41:42,960 --> 00:41:47,440
But here the reading is 153.6 grams.

496
00:41:47,440 --> 00:41:51,320
That's nearly four grams more
than before it was heated.

497
00:41:51,320 --> 00:41:54,840
Here's where Lavoisier
had his flash of inspiration.

498
00:41:54,840 --> 00:41:58,320
Maybe phlogiston isn't given off
when a substance is heated.

499
00:41:58,320 --> 00:42:01,760
Instead, maybe it absorbs
some kind of air.

500
00:42:01,760 --> 00:42:04,120
That would explain this increase.

501
00:42:04,120 --> 00:42:08,720
But if that was true,
what was it that was being added?

502
00:42:13,240 --> 00:42:17,800
'Fresh from his conversation with
Priestley, Lavoisier decided to

503
00:42:17,800 --> 00:42:22,720
'repeat Priestley's experiment,
only in reverse.'

504
00:42:26,000 --> 00:42:29,640
He heated some mercury
inside a sealed container

505
00:42:29,640 --> 00:42:34,280
until it turned into mercuric oxide,
which is the same substance

506
00:42:34,280 --> 00:42:37,640
that Priestley had used
in his experiment.

507
00:42:37,640 --> 00:42:43,040
He measured the amount of air
that was absorbed by the mercury
when it was heated.

508
00:42:43,040 --> 00:42:45,400
He then heated the mercuric oxide

509
00:42:45,400 --> 00:42:50,240
and observed that the amount of air
released was exactly the same

510
00:42:50,240 --> 00:42:54,320
as the amount of air that had been
absorbed by the mercury
when it was heated.

511
00:42:54,320 --> 00:42:58,880
So in a flash of inspiration, he
realised that something in the air

512
00:42:58,880 --> 00:43:03,160
had been taken in by the mercury
to make the mercuric oxide.

513
00:43:03,160 --> 00:43:05,960
And that same gas
had then been released.

514
00:43:05,960 --> 00:43:11,560
He had the courage to conclude
that this gas had nothing
to do with phlogiston.

515
00:43:11,560 --> 00:43:14,960
In fact, it was a brand new element.

516
00:43:14,960 --> 00:43:17,640
Lavoisier called it oxygen.

517
00:43:17,640 --> 00:43:23,320
So thanks to Priestley's experiment,
Lavoisier had exposed the truth

518
00:43:23,320 --> 00:43:27,120
of the red herring that had
hampered chemistry for a century.

519
00:43:27,120 --> 00:43:32,920
Finally, Lavoiser had shown that
phlogiston simply didn't exist.

520
00:43:35,560 --> 00:43:40,280
'Lavoisier had freed chemistry
from the shackles of phlogiston,

521
00:43:40,280 --> 00:43:43,240
'the remnants
of the medieval worldview.

522
00:43:43,240 --> 00:43:45,480
'And he'd pioneered
a scientific method

523
00:43:45,480 --> 00:43:50,000
'and so could make rapid progress
in mapping the elements.

524
00:43:50,000 --> 00:43:55,680
'But to Priestley's anger, Lavoisier
claimed HE had discovered oxygen,

525
00:43:55,680 --> 00:43:59,280
'because he recognised it
as a new element.'

526
00:43:59,280 --> 00:44:05,360
Trying to resolve who should get the
glory proved to be a messy business.

527
00:44:05,360 --> 00:44:10,280
An embittered war of words
and reputations broke out
between England and France.

528
00:44:10,280 --> 00:44:15,080
Priestley was enraged that Lavoisier
had tried to steal his thunder,

529
00:44:15,080 --> 00:44:19,720
and he had a point because
Lavoisier's experiments on oxygen

530
00:44:19,720 --> 00:44:23,640
weren't completed
until after he'd met Priestley.

531
00:44:25,160 --> 00:44:28,240
'Lavoisier
may not have discovered oxygen,

532
00:44:28,240 --> 00:44:31,120
'but he had recognised
its significance.

533
00:44:31,120 --> 00:44:34,400
'And it is Lavoisier, not Priestley,

534
00:44:34,400 --> 00:44:38,240
'who is known as
the Father of Chemistry.

535
00:44:38,240 --> 00:44:43,240
'The discovery of oxygen
had finally crushed any vestiges

536
00:44:43,240 --> 00:44:46,760
'of the Greek concept
of the four elements.'

537
00:44:46,760 --> 00:44:50,400
Water was made of hydrogen
and oxygen.

538
00:44:50,400 --> 00:44:55,160
Earth and air were a whole
hotchpotch of different elements.

539
00:44:55,160 --> 00:44:59,920
And fire, well,
that wasn't an element at all.

540
00:45:04,720 --> 00:45:08,200
Chemistry was being hauled into
the modern era.

541
00:45:08,200 --> 00:45:11,320
It was an age when chemists
were splitting matter,

542
00:45:11,320 --> 00:45:13,160
making great discoveries,

543
00:45:13,160 --> 00:45:16,520
just trying to understand
what our world was made of.

544
00:45:16,520 --> 00:45:20,160
But there still didn't
seem to be any order,

545
00:45:20,160 --> 00:45:22,600
any logic to their findings,

546
00:45:22,600 --> 00:45:26,080
just random elements dotted around
the chemical landscape.

547
00:45:31,120 --> 00:45:36,200
'Lavoisier was the first scientist
to define what an element was -

548
00:45:36,200 --> 00:45:42,800
'a substance
that could not be decomposed
by existing chemical means.'

549
00:45:42,800 --> 00:45:44,720
This is the manuscript.

550
00:45:44,720 --> 00:45:50,080
'And he set about drawing up a
definitive list of all the elements.

551
00:45:50,080 --> 00:45:55,120
'Now, 33 replaced the ancient four.'

552
00:45:55,120 --> 00:45:57,480
Wow!

553
00:45:57,480 --> 00:46:03,560
So this is it. This is Lavoisier's
original list of elements.

554
00:46:03,560 --> 00:46:06,720
It's in French
and it's in his handwriting,

555
00:46:06,720 --> 00:46:09,840
but I can still sort of pick out
what it says.

556
00:46:09,840 --> 00:46:14,080
He's divided them up into four
groups. Four categories of elements.

557
00:46:14,080 --> 00:46:20,680
There's the gases, the non-metals,
metals and earths.

558
00:46:20,680 --> 00:46:25,200
You can see among the gases
he's got oxygen and hydrogen.

559
00:46:25,200 --> 00:46:26,840
He didn't get it all right.

560
00:46:26,840 --> 00:46:32,680
I see he lists here arsenic
and antimony among his metals.

561
00:46:32,680 --> 00:46:35,920
Today, they're not considered
to be metals.

562
00:46:35,920 --> 00:46:39,960
But even more fascinating,
he has lumiere, or light,

563
00:46:39,960 --> 00:46:45,640
and calorique, heat, listed
among his elements in the gases.

564
00:46:45,640 --> 00:46:49,400
Of course light and heat,
we know now to be just pure energy.

565
00:46:49,400 --> 00:46:55,120
But these mistakes apart, this was
a huge leap forward in chemistry.

566
00:46:55,120 --> 00:46:59,960
It was an early realisation
that perhaps there was
some order to the elements.

567
00:46:59,960 --> 00:47:04,440
Some grand pattern to
the building blocks of our world.

568
00:47:04,440 --> 00:47:07,840
'And Lavoisier didn't stop there.

569
00:47:07,840 --> 00:47:13,280
'He created a system to classify the
discoveries of many other chemists,

570
00:47:13,280 --> 00:47:18,640
'and set out to transform
the language of chemistry.'

571
00:47:18,640 --> 00:47:22,760
He began a revolution
of scientific vocabulary,

572
00:47:22,760 --> 00:47:26,600
replacing the picturesque and poetic
with precision.

573
00:47:26,600 --> 00:47:31,360
So dephlogisticated air
became oxygen.

574
00:47:31,360 --> 00:47:35,040
Astringent mars saffron

575
00:47:35,040 --> 00:47:37,240
became iron oxide.

576
00:47:37,240 --> 00:47:40,880
Oil of vitriol
became sulphuric acid,

577
00:47:40,880 --> 00:47:46,080
and philosophical wool
became zinc oxide.

578
00:47:46,080 --> 00:47:51,120
At last there was a universal
language to identify the elements.

579
00:47:51,120 --> 00:47:55,400
Maybe it's a shame that
some of these exotic names
have been replaced,

580
00:47:55,400 --> 00:47:59,080
but in a way I admire
Lavoisier's logic.

581
00:47:59,080 --> 00:48:01,840
He revolutionised chemistry,

582
00:48:01,840 --> 00:48:04,680
but other revolutions
were in the air.

583
00:48:07,000 --> 00:48:12,120
'In 1789, the French Revolution
would have terrible consequences

584
00:48:12,120 --> 00:48:15,640
'for both Lavoisier
and his rival Priestley.

585
00:48:15,640 --> 00:48:19,720
'In England, Priestley's
sympathies for the uprising

586
00:48:19,720 --> 00:48:22,280
'gained him unwelcome attention.'

587
00:48:22,280 --> 00:48:25,960
Things came to a head in 1791
when an angry mob,

588
00:48:25,960 --> 00:48:29,520
frightened that revolution
would find its way to England,

589
00:48:29,520 --> 00:48:34,280
descended on his new home
and burnt it to the ground.

590
00:48:35,480 --> 00:48:39,480
'Thanks to a tip-off,
Priestley escaped unharmed,

591
00:48:39,480 --> 00:48:43,080
'but decided to flee to America.'

592
00:48:43,080 --> 00:48:46,080
Lavoisier was not so lucky.

593
00:48:46,080 --> 00:48:48,400
Despised for his government work,

594
00:48:48,400 --> 00:48:52,280
Lavoisier and 28 other
tax collectors were tried

595
00:48:52,280 --> 00:48:55,960
and found guilty of conspiring
against the people of France.

596
00:48:55,960 --> 00:49:02,080
He was brought here to Le Place
de la Revolution that same day -
May 8th, 1794.

597
00:49:02,080 --> 00:49:05,960
And in 35 minutes,
they were all executed.

598
00:49:05,960 --> 00:49:09,680
The next day the French
mathematician Joseph Legrange

599
00:49:09,680 --> 00:49:13,680
commented, "It took them just
an instant to cut off that head,

600
00:49:13,680 --> 00:49:17,880
"but another 100 years may pass
before another like it is seen."

601
00:49:20,120 --> 00:49:23,480
'Lavoisier left
an incredible legacy.

602
00:49:23,480 --> 00:49:28,600
'He had cast out old dogma
and replaced it with
an empirical approach.'

603
00:49:31,160 --> 00:49:33,520
'There was no going back.'

604
00:49:35,040 --> 00:49:40,560
'Experimentation could now prove or
disprove the most radical of ideas.

605
00:49:40,560 --> 00:49:45,680
'But scientists were still convinced
that more elements must be out there

606
00:49:45,680 --> 00:49:49,640
'and were desperate to find
new ways of revealing them.

607
00:49:49,640 --> 00:49:53,760
'Matter remained
fundamentally impenetrable.

608
00:49:53,760 --> 00:49:57,560
'And it would take a powerful
and dangerous force

609
00:49:57,560 --> 00:50:00,600
'to find a new way
of splitting it apart.'

610
00:50:03,120 --> 00:50:08,440
'Enter Humphry Davy, a wild,
charismatic Cornish scientist

611
00:50:08,440 --> 00:50:11,560
'who frequently courted jeopardy.

612
00:50:11,560 --> 00:50:16,160
'He was Professor of Chemistry
at the Royal Institution in London.

613
00:50:16,160 --> 00:50:21,960
'On 6th October 1807, Davy
was working away in the basement

614
00:50:21,960 --> 00:50:26,640
'where he'd adapted the servants'
quarters to make a lab.'

615
00:50:26,640 --> 00:50:32,320
He had been working with some
crystalline salts...called potash.

616
00:50:32,320 --> 00:50:35,360
Lavoisier had been
unable to break it down,

617
00:50:35,360 --> 00:50:37,880
and reckoned that
it was an element.

618
00:50:37,880 --> 00:50:40,160
But Davy wasn't convinced.

619
00:50:40,160 --> 00:50:43,760
He suspected that potash was
made up of more than one element.

620
00:50:43,760 --> 00:50:48,960
But no matter how hard people had
tried, potash had defeated them.

621
00:50:48,960 --> 00:50:52,760
There didn't seem to be any way
that chemistry could break it down.

622
00:50:56,640 --> 00:50:59,680
'Now Davy had a new idea.

623
00:50:59,680 --> 00:51:03,040
'The first electric battery
had recently been invented.'

624
00:51:04,600 --> 00:51:09,200
'It was very simple.
Rows of metal plates and cardboard,

625
00:51:09,200 --> 00:51:11,600
'soaked in salt water.'

626
00:51:13,400 --> 00:51:17,640
'But it made the world's first
continuous current.

627
00:51:17,640 --> 00:51:21,880
'I'm going to use the same principle
to try to create electricity.'

628
00:51:24,960 --> 00:51:28,880
I've got a copper coin connected to
a zinc washer via a copper wire,

629
00:51:28,880 --> 00:51:33,120
and if I have enough of these
linking up these wine glasses

630
00:51:33,120 --> 00:51:37,120
filled only with salt water,
then I can create a circuit.

631
00:51:37,120 --> 00:51:41,720
Now if I connect up the copper
coin on one side, via a lamp,

632
00:51:41,720 --> 00:51:44,400
with the zinc washer on the other,

633
00:51:44,400 --> 00:51:47,000
I've created electricity.
The light's come on.

634
00:51:47,000 --> 00:51:52,480
I've made electricity just from
glasses filled with salt water
and two different metals.

635
00:51:52,480 --> 00:51:57,400
Most chemists at the time thought
that the effect had something to do
with the different metals.

636
00:51:57,400 --> 00:52:00,560
But Davy believed
there was a deeper reason.

637
00:52:00,560 --> 00:52:05,960
That it was a chemical reaction that
was causing the electric current.

638
00:52:05,960 --> 00:52:10,760
'But if that were the case, then
perhaps the reverse could be true,

639
00:52:10,760 --> 00:52:15,080
'and an electric current
could cause a chemical reaction.

640
00:52:15,080 --> 00:52:19,040
'Davy resolved to find out.

641
00:52:19,040 --> 00:52:24,640
'Chemist Dr Hal Sosabowski and I are
going to attempt Davy's experiment

642
00:52:24,640 --> 00:52:27,840
'to find out what Davy
actually witnessed.'

643
00:52:27,840 --> 00:52:29,960
Welcome to the lab. Thank you.

644
00:52:29,960 --> 00:52:33,160
Right, so we're going
to be splitting potash.

645
00:52:33,160 --> 00:52:36,600
The first thing we are going to
have to do is melt the potash.

646
00:52:36,600 --> 00:52:40,160
It's got a relatively low melting
point of 360, which means we can

647
00:52:40,160 --> 00:52:43,960
melt it with a Bunsen flame
and a blowtorch.

648
00:52:47,440 --> 00:52:53,600
So almost straight away
you're seeing that glistening
of the liquid forming.

649
00:52:53,600 --> 00:52:57,200
It's melting back
into the receptacle.

650
00:52:57,200 --> 00:53:02,280
This, I gather in the melted state
is very dangerous, very caustic?

651
00:53:02,280 --> 00:53:08,520
Exceptionally so. If it splashed
on to us it would be instantly
disfiguring, instant blindness.

652
00:53:08,520 --> 00:53:10,200
In a solid state it's bad enough,

653
00:53:10,200 --> 00:53:13,320
but in the molten state
it's really hideously dangerous.

654
00:53:13,320 --> 00:53:16,920
So it's scary then to think what it
must have been like in Davy's lab.

655
00:53:16,920 --> 00:53:20,000
People losing fingers and eyes
and getting disfigured?

656
00:53:20,000 --> 00:53:22,400
Yes, it was an innocent age
in some regards.

657
00:53:22,400 --> 00:53:25,800
He would have been standing there in
his tweeds and bow tie, no glasses.

658
00:53:25,800 --> 00:53:28,560
That's the way science was.
They were all pioneers.

659
00:53:28,560 --> 00:53:31,400
And don't forget, Davy didn't know
what he was looking for.

660
00:53:31,400 --> 00:53:36,880
He didn't know he was looking for
a very reactive metal that
would actually catch fire in air.

661
00:53:36,880 --> 00:53:39,320
So there was a double danger,
if you will.

662
00:53:40,480 --> 00:53:42,840
Over here
this is a modern-day lorry battery.

663
00:53:42,840 --> 00:53:45,280
It provides 12 volts.
Enough for our experiment.

664
00:53:45,280 --> 00:53:48,320
And we've got carbon electrodes,
and some jump leads.

665
00:53:48,320 --> 00:53:50,320
So we're all ready
to split our potash.

666
00:53:50,320 --> 00:53:53,360
We just don't know what it's
going to do when we put this in.

667
00:53:55,120 --> 00:53:58,280
'The electric currents passing
through the melted potash

668
00:53:58,280 --> 00:54:02,400
'is creating an unpredictable
and volatile chemical reaction,

669
00:54:02,400 --> 00:54:06,360
'wrenching apart the electrically
charged particles in the potash.

670
00:54:06,360 --> 00:54:10,080
'But is it enough to split it?'

671
00:54:10,080 --> 00:54:12,400
It's all changed colour.

672
00:54:12,400 --> 00:54:15,920
The electrodes are being consumed
because it's a caustic environment.

673
00:54:15,920 --> 00:54:19,000
Oh, look, there it is!
Oh, that pink flash?

674
00:54:19,000 --> 00:54:23,480
Yes - that's where the potassium
is being produced.
And it's reacting straight away.

675
00:54:23,480 --> 00:54:27,480
That's the potassium on the surface
burning quickly in oxygen.

676
00:54:27,480 --> 00:54:29,760
There's another one, look.
Yes, it's reacting.

677
00:54:29,760 --> 00:54:33,240
Just like a tiny pink matchstick
popping on the surface.

678
00:54:33,240 --> 00:54:37,560
Exactly. And that sort of noise,
almost like a match flare,
is the potassium flaring off.

679
00:54:39,160 --> 00:54:42,200
And that's what he would have seen.
Just there and then.

680
00:54:42,200 --> 00:54:44,360
A beautiful lilac flame.

681
00:54:44,360 --> 00:54:48,640
'Where others had failed,
Davy succeeded.

682
00:54:48,640 --> 00:54:53,160
'He'd split potash into its
most fundamental ingredients,

683
00:54:53,160 --> 00:54:59,080
'forcing out an element never seen
before. Potassium.'

684
00:54:59,080 --> 00:55:04,320
I can't possibly imagine
the excitement Davy would have felt.

685
00:55:04,320 --> 00:55:07,440
He was discovering this new element
for the very first time.

686
00:55:07,440 --> 00:55:09,440
No-one else in the world
had seen it.

687
00:55:09,440 --> 00:55:15,280
His assistant reckoned that Davy
did a quick dance around the lab
when he made the discovery.

688
00:55:18,040 --> 00:55:20,680
'Potassium.

689
00:55:20,680 --> 00:55:26,040
'It's a soft, silvery metal
which can be cut like cheese.

690
00:55:26,040 --> 00:55:32,400
'For a minute it shimmers
like steel, then tarnishes in air.

691
00:55:32,400 --> 00:55:36,600
'Potassium
is essential to human life.

692
00:55:36,600 --> 00:55:39,120
'Our bodies need a constant supply

693
00:55:39,120 --> 00:55:42,280
'to keep the muscles
and kidneys working.

694
00:55:42,280 --> 00:55:46,000
'It also helps to transmit
nerve impulses.

695
00:55:46,000 --> 00:55:48,080
'But it's a killer, too.

696
00:55:48,080 --> 00:55:52,960
'A large dose of potassium chloride
can result in a fatal heart attack.'

697
00:55:56,280 --> 00:56:00,600
'When potassium touches water,
it reacts explosively,

698
00:56:00,600 --> 00:56:03,960
'releasing hydrogen
and leaving behind potash.'

699
00:56:06,040 --> 00:56:09,000
'But it's abundant
as a salt in seawater.'

700
00:56:11,080 --> 00:56:16,960
'It took Humphry Davy to prise it
from nature and make it visible.'

701
00:56:18,880 --> 00:56:25,160
Davy seemed to be able to
penetrate further into the seemingly
unfathomable world of the elements -

702
00:56:25,160 --> 00:56:28,000
further even than Lavoisier
had thought possible.

703
00:56:28,000 --> 00:56:31,000
But potassium
was just the beginning.

704
00:56:33,720 --> 00:56:38,240
In time, Davy added six new elements
to Lavoisier's list,

705
00:56:38,240 --> 00:56:44,120
and he confirmed that substances
like chlorine and iodine
were also elements.

706
00:56:44,120 --> 00:56:47,280
He was a maverick
in the world of chemistry -

707
00:56:47,280 --> 00:56:51,600
fearless, even reckless in the face
of a hazardous experiment.

708
00:56:51,600 --> 00:56:54,680
For him,
danger was part of the territory.

709
00:56:54,680 --> 00:56:59,720
And it was probably his inhalations
of those chemicals over the course
of his life that took their toll.

710
00:56:59,720 --> 00:57:05,400
He died in May 1829, aged 50.

711
00:57:05,400 --> 00:57:12,000
'His quest for knowledge,
to delve deeper into
the concealed natural world,

712
00:57:12,000 --> 00:57:15,000
'perhaps cost him his life.

713
00:57:15,000 --> 00:57:20,320
'But the step he made for scientific
progress is immeasurable.'

714
00:57:20,320 --> 00:57:26,480
By the time of Davy's death,
the idea of the elements
was firmly established.

715
00:57:26,480 --> 00:57:31,080
55 of our planet's building blocks
had been identified.

716
00:57:31,080 --> 00:57:36,000
And the world had a new science -
chemistry.

717
00:57:41,640 --> 00:57:46,240
'Next time,
I'm going to take up the quest
of the chemical pioneers...'

718
00:57:46,240 --> 00:57:47,920
Well, my arm's burning up.

719
00:57:47,920 --> 00:57:51,960
'..as they struggled to make sense
of elemental chaos.

720
00:57:51,960 --> 00:57:55,440
'I'll find out
how a scientist's dream

721
00:57:55,440 --> 00:57:59,000
was to become one of our
most beautiful creations -

722
00:57:59,000 --> 00:58:01,680
'the periodic table.

723
00:58:01,680 --> 00:58:06,200
'And I'll delve into
the subatomic world to reveal

724
00:58:06,200 --> 00:58:11,160
'the hidden pattern of the universe,
the order of the elements.'

725
00:58:26,440 --> 00:58:29,800
Subtitles by Red Bee Media Ltd

726
00:58:29,800 --> 00:58:33,240
E-mail subtitling@bbc.co.uk