1
00:00:19,412 --> 00:00:21,039
Know what this is?

2
00:00:21,181 --> 00:00:22,978
Invisible technology.

3
00:00:23,116 --> 00:00:24,208
Well, it is, isn't it?

4
00:00:24,350 --> 00:00:26,079
I mean, something
you hardly think about.

5
00:00:26,219 --> 00:00:28,119
And yet
what extraordinary connections

6
00:00:28,254 --> 00:00:29,812
this humdrum stuff has.

7
00:01:00,487 --> 00:01:02,580
And just this once,
I'm going to tell you in advance

8
00:01:02,722 --> 00:01:04,781
where it's going to lead us to
at the end of the show:

9
00:01:04,924 --> 00:01:09,418
back here to something in this scene
you're already looking at.

10
00:01:09,562 --> 00:01:11,029
See if you can spot it.

11
00:01:11,164 --> 00:01:14,065
Okay, now I've given you a clue,
it should be easy.

12
00:01:14,200 --> 00:01:15,690
By the end of the show,

13
00:01:15,835 --> 00:01:18,804
if you have not already decided
where it is we're headed,

14
00:01:18,938 --> 00:01:20,633
it'll be "High Time."

15
00:01:43,830 --> 00:01:45,695
2125.

16
00:01:45,832 --> 00:01:47,094
502.

17
00:01:56,543 --> 00:02:00,707
The story begins here,
deep below London, in 1940.

18
00:02:00,847 --> 00:02:01,836
Battle of Britain.

19
00:02:01,981 --> 00:02:04,040
British air defense headquarters.

20
00:02:04,184 --> 00:02:05,981
England, France.

21
00:02:06,119 --> 00:02:08,417
Okay.

22
00:02:08,555 --> 00:02:12,116
We are here.
The Germans are here.

23
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Or rather here, here, and here,
coming across the Channel towards us.

24
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No problem.

25
00:02:18,798 --> 00:02:21,995
Radar stations
here, here, and here

26
00:02:22,135 --> 00:02:24,865
will spot them and save us all.

27
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But the radar aerials
along the British coastline

28
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are so big,
they're a very easy target.

29
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The answer:

30
00:02:33,546 --> 00:02:35,173
cling wrap.

31
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Technical term: polythene.

32
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First discovered by accident in 1933

33
00:02:41,321 --> 00:02:44,313
when there was an explosion
in an English chemical lab--

34
00:02:44,457 --> 00:02:46,288
they were actually looking
for dye--

35
00:02:46,426 --> 00:02:50,658
and there, stuck to the bits of glass,
was polythene.

36
00:02:50,797 --> 00:02:53,027
By the time they got it
into production,

37
00:02:53,166 --> 00:02:55,634
it was just what
the defense staff here needed

38
00:02:55,768 --> 00:03:00,364
and just in time for the first
of the really massive air raids.

39
00:03:13,353 --> 00:03:16,720
In all the wartime movies,
it looks a piece of cake, doesn't it?

40
00:03:16,856 --> 00:03:19,416
Spot the enemy aircraft
on your glowing radar screens,

41
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then guide the fighters
to their targets.

42
00:03:21,894 --> 00:03:23,589
Tally ho and all that.

43
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Except the easiest target for the enemy
is big radar aerials.

44
00:03:32,372 --> 00:03:33,862
Small aerials are safer,

45
00:03:34,007 --> 00:03:37,033
but they make small signals
that need special insulation.

46
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But what insulation?

47
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Polythene turned out
to be great insulation.

48
00:03:50,456 --> 00:03:51,616
One of the ways
you make polythene

49
00:03:51,691 --> 00:03:54,057
is by blowing bubbles of it
when it's melted.

50
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Makes thin films like this.

51
00:03:57,530 --> 00:03:59,862
Just like soap bubbles like this.

52
00:04:01,334 --> 00:04:02,858
They're both colloids.

53
00:04:03,002 --> 00:04:03,991
That's molecules

54
00:04:04,137 --> 00:04:07,129
that make squeezy, stretchy,
slippery stuff.

55
00:04:07,273 --> 00:04:10,003
So a lot of what polythene
people know about polythene

56
00:04:10,143 --> 00:04:12,839
comes from what soap people know
about soap.

57
00:04:12,979 --> 00:04:14,503
Interesting things, soap bubbles.

58
00:04:14,647 --> 00:04:17,411
A Scottish scientist
once kept a soap bubble alive,

59
00:04:17,550 --> 00:04:19,381
so to speak, for three years.

60
00:04:21,621 --> 00:04:23,555
Of course, the bible on soap
was written

61
00:04:23,690 --> 00:04:25,214
at the beginning
of the 19th century

62
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by a fellow who did
most of his work in Paris

63
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name of Chevreul.

64
00:04:30,496 --> 00:04:34,125
And Chevreul's contribution
to the sum of total knowledge

65
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was that he found out
why soap makes you clean.

66
00:04:43,843 --> 00:04:47,006
Turned out, it pulls
the particles of dirt off you

67
00:04:47,146 --> 00:04:50,309
and kind of hooks them onto
the surrounding water molecules,

68
00:04:50,450 --> 00:04:53,476
so when you rub,
the dirt floats off your skin,

69
00:04:53,619 --> 00:04:55,314
into the water,
and then gets grabbed

70
00:04:55,455 --> 00:04:58,515
by groups of big soapy molecules
called micelles

71
00:04:58,658 --> 00:05:00,990
that stop it
sticking back onto you again.

72
00:05:01,127 --> 00:05:04,028
So you get clean
and stay clean.

73
00:05:04,163 --> 00:05:08,031
Meanwhile, why did he
get into soap at all?

74
00:05:08,167 --> 00:05:10,135
Because he was really a dyer,

75
00:05:10,269 --> 00:05:14,069
and dyes interact with cloth fibers
just like soap does.

76
00:05:14,207 --> 00:05:18,371
And Chevreul's obsession
was to make intense color dyes

77
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that wouldn't wash or fade out.

78
00:05:21,381 --> 00:05:25,818
So instead of looking at the dyes,
he looked at how you see color.

79
00:05:25,952 --> 00:05:28,113
Chevreul called
what he then discovered

80
00:05:28,254 --> 00:05:30,688
"simultaneous contrast."

81
00:05:30,823 --> 00:05:36,318
He said any color's intensity
depends on what you put next to it.

82
00:05:37,964 --> 00:05:39,124
You see the effect

83
00:05:39,265 --> 00:05:41,460
with these different-colored
tapestry threads

84
00:05:41,601 --> 00:05:44,229
the further back
from the tapestry you go.

85
00:05:46,105 --> 00:05:47,538
These, as it happens,

86
00:05:47,673 --> 00:05:49,971
are the greatest tapestries
of all time,

87
00:05:50,109 --> 00:05:54,239
made in the 18th century at the
Gobelin tapestry factory here in France

88
00:05:54,380 --> 00:05:56,644
to warm up the walls
of the king's palaces,

89
00:05:56,783 --> 00:05:59,547
like Versailles,
which is far from hot.

90
00:05:59,685 --> 00:06:02,779
And that's why Chevreul was doing
what he was doing with soap,

91
00:06:02,922 --> 00:06:06,358
because he was director of dying
at the Gobelin tapestry factory,

92
00:06:06,492 --> 00:06:09,552
and, as I said earlier,
the way a dye acts on fiber

93
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is very much like the way soap does.

94
00:06:11,564 --> 00:06:13,259
Anyway, take a look

95
00:06:13,399 --> 00:06:15,890
at a few million dollars' worth
of colored thread.

96
00:06:50,837 --> 00:06:53,397
I'll do just one more bit
of art gallery stuff,

97
00:06:53,539 --> 00:06:55,564
and then we're off
to exotic foreign locations

98
00:06:55,708 --> 00:06:58,370
on this trail
that started with cling wrap.

99
00:06:58,511 --> 00:07:00,638
50 years before Chevreul,

100
00:07:00,780 --> 00:07:03,578
Gobelin tapestry design
suddenly went very subtle,

101
00:07:03,716 --> 00:07:04,876
because they started working

102
00:07:05,017 --> 00:07:06,609
with a new kind
of interlocking stitch

103
00:07:06,752 --> 00:07:09,243
so you could weave
very subtle designs.

104
00:07:09,388 --> 00:07:12,118
So the then boss hired
a couple of painters

105
00:07:12,258 --> 00:07:14,749
to design this kind of pattern.

106
00:07:18,731 --> 00:07:20,858
Subtle needlework, right?

107
00:07:21,000 --> 00:07:22,524
But you've probably
already guessed

108
00:07:22,668 --> 00:07:25,262
you're not looking
at a European design.

109
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And these Chinese figures
are a clue

110
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to why the world-famous
Gobelin factory

111
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didn't begin life
as a tapestry factory at all.

112
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The reason was that back
in the early 17th century,

113
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the West had rediscovered
the mysterious East,

114
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and in spite of the fact
that getting out here

115
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involved months at sea
in leaky boats

116
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with rotten food and scurvy,

117
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people were lining up
for the privilege,

118
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because the marketplaces
of China and Japan

119
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were full of the kind of stuff

120
00:07:55,368 --> 00:07:57,859
that would make any
European antiques dealer

121
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seriously rich seriously quick.

122
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That's because in the early part
of the 18th century,

123
00:08:08,948 --> 00:08:11,348
the hot stuff
for doing up your house

124
00:08:11,484 --> 00:08:15,648
was anything from the Far East:
rugs, silks, porcelain,

125
00:08:15,788 --> 00:08:17,619
and the one thing
the market turned up

126
00:08:17,757 --> 00:08:19,520
that was to turn out
to be a real craze

127
00:08:19,659 --> 00:08:23,561
and the reason the Gobelin factory
was set up in the first place,

128
00:08:23,696 --> 00:08:28,963
not to make tapestries at all;
to make fake lacquer furniture.

129
00:08:29,101 --> 00:08:31,626
The real lacquerwork stuff
was turning up in Europe

130
00:08:31,771 --> 00:08:33,830
from out here by 1610,

131
00:08:33,973 --> 00:08:37,238
but it was such a smash hit,
prices went through the roof.

132
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So the French cornered
the market with cheap imitations.

133
00:08:41,547 --> 00:08:45,574
Of course, it wasn't
just furniture that cost a lot;

134
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a dealer could make 150%
on pretty much anything

135
00:08:48,955 --> 00:08:50,718
he wanted to bring back
from the Far East.

136
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And there was one particular
bunch of Europeans

137
00:08:53,426 --> 00:08:55,291
who could never resist
the opportunity

138
00:08:55,428 --> 00:08:57,896
to make that kind of profit:
the Dutch.

139
00:08:58,030 --> 00:09:01,727
By the 17th century, Europe's
number one mail-order company.

140
00:09:01,867 --> 00:09:04,427
"We will get you anything,"
they said, "from anywhere...

141
00:09:04,570 --> 00:09:07,130
for the right price."

142
00:09:07,273 --> 00:09:08,797
Which is why
they were among the first

143
00:09:08,941 --> 00:09:10,875
to rendezvous out here
in southeast Asia

144
00:09:11,010 --> 00:09:13,877
with the trading junks bringing cargos
of lacquered furniture

145
00:09:14,013 --> 00:09:17,540
and all kinds of other
profitable goodies out of China.

146
00:09:27,326 --> 00:09:29,521
Unfortunately, right from the start,

147
00:09:29,662 --> 00:09:30,822
the Dutch had a small problem

148
00:09:30,963 --> 00:09:34,091
with actually getting
to the rendezvous.

149
00:09:34,233 --> 00:09:35,723
Take a look at this map.

150
00:09:36,936 --> 00:09:37,994
We are here.

151
00:09:38,137 --> 00:09:39,263
Now, at the time,

152
00:09:39,405 --> 00:09:41,373
there's only two ways
to get here from Holland:

153
00:09:41,507 --> 00:09:43,907
this way,
south and across the Pacific;

154
00:09:44,043 --> 00:09:46,739
and this way,
south around Africa.

155
00:09:46,879 --> 00:09:49,143
This route is sewn up
by the Portuguese

156
00:09:49,281 --> 00:09:51,408
and this route by the Spanish.

157
00:09:51,550 --> 00:09:54,883
You try either way,
and you got blown out of the water,

158
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which wasn't going to stop the Dutch.

159
00:09:57,256 --> 00:09:58,951
All the explorers and investors

160
00:09:59,091 --> 00:10:01,457
from the six main Dutch ports
got together,

161
00:10:01,594 --> 00:10:04,392
set up a joint venture called
the Dutch East India Company,

162
00:10:04,530 --> 00:10:07,021
and started looking at ways
around this minor problem

163
00:10:07,166 --> 00:10:09,464
of how to get at
all that profit out East.

164
00:10:09,602 --> 00:10:12,435
And once they'd started
really thinking about the problem,

165
00:10:12,571 --> 00:10:15,540
the solution appeared
to be idiotically simple.

166
00:10:15,675 --> 00:10:18,439
lf you couldn't go south,
go north.

167
00:10:18,577 --> 00:10:21,671
You're smiling,
because you know what they didn't,

168
00:10:21,814 --> 00:10:23,304
because it wasn't on their maps,

169
00:10:23,449 --> 00:10:25,144
because they didn't know
it existed.

170
00:10:25,284 --> 00:10:26,751
This:

171
00:10:37,563 --> 00:10:39,224
The polar ice pack.

172
00:10:39,365 --> 00:10:40,662
Still, ignorance is bliss.

173
00:10:40,800 --> 00:10:44,236
And so on April the 23rd, 1607,

174
00:10:44,370 --> 00:10:46,429
it was off out here
to meet these junks

175
00:10:46,572 --> 00:10:48,870
for an English captain
called Henry Hudson

176
00:10:49,008 --> 00:10:50,305
that the Dutch had hired

177
00:10:50,443 --> 00:10:54,436
and, as it was to turn out,
sent in the wrong direction.

178
00:10:58,017 --> 00:10:59,177
Now, in the modern world,

179
00:10:59,318 --> 00:11:02,287
we're so used to going straight
where we want to go

180
00:11:02,421 --> 00:11:05,788
that you might be amused
at the way Hudson went about it.

181
00:11:05,925 --> 00:11:06,914
Here's his mission:

182
00:11:07,059 --> 00:11:09,425
to find a northwest passage
through here

183
00:11:09,562 --> 00:11:10,654
to get to the Far East.

184
00:11:10,796 --> 00:11:13,560
So over four months,
thanks to the pack ice,

185
00:11:13,699 --> 00:11:15,394
here's what Henry did.

186
00:11:15,534 --> 00:11:18,628
London, Shetland,

187
00:11:18,771 --> 00:11:21,899
Iceland, Greenland,

188
00:11:22,041 --> 00:11:26,603
Spitsbergen, Spitsbergen,

189
00:11:26,746 --> 00:11:31,410
Spitsbergen,
Greenland, Greenland,

190
00:11:31,550 --> 00:11:33,745
give up and go home.

191
00:11:33,886 --> 00:11:36,354
Failure?
Not a bit of it.

192
00:11:36,489 --> 00:11:38,548
Because all that bumping
into Spitsbergen meant

193
00:11:38,691 --> 00:11:40,181
he charted the place pretty well,

194
00:11:40,326 --> 00:11:42,521
so when he got back,
he was at least able

195
00:11:42,661 --> 00:11:45,186
to tell his Dutch bosses
where to land their whales,

196
00:11:45,331 --> 00:11:49,529
because up north, apart from ice,
all he'd seen was whales,

197
00:11:49,668 --> 00:11:53,195
at that time the most
financially rewarding thing afloat

198
00:11:53,339 --> 00:11:55,364
this side
of a Spanish treasure ship.

199
00:11:58,244 --> 00:12:01,236
A whale is basically bone,
blubber, and oil.

200
00:12:01,380 --> 00:12:04,781
They used whalebone
anywhere we'd use plastic today.

201
00:12:04,917 --> 00:12:08,409
Blubber went into candles and soap,
and the oil lit lamps.

202
00:12:08,554 --> 00:12:12,354
So you could get very rich
by just doing this.

203
00:12:20,633 --> 00:12:22,430
Arctic whaling lasted 300 years,

204
00:12:22,668 --> 00:12:26,104
and it's a perfect example
of the strange way history works,

205
00:12:26,238 --> 00:12:29,503
because Henry Hudson wouldn't
have even had a bad map

206
00:12:29,642 --> 00:12:31,906
if it hadn't been
for a fellow here in Belgium

207
00:12:32,044 --> 00:12:36,310
who sold French underwear,
fancy leather, wine, mirrors,

208
00:12:36,448 --> 00:12:38,541
and holy books.

209
00:12:38,684 --> 00:12:42,347
This was his printing shop
in Antwerp,

210
00:12:42,488 --> 00:12:46,083
and he was the hottest publisher
in the 16th century,

211
00:12:46,225 --> 00:12:50,559
and his name
was Christopher Plantin.

212
00:12:53,799 --> 00:12:55,164
Why he was such a big shot

213
00:12:55,301 --> 00:12:58,464
is because he'd talked himself
into the biggest print job ever:

214
00:13:03,475 --> 00:13:06,933
over 1,000 copies of what
his sales pitch referred to

215
00:13:07,079 --> 00:13:10,776
as "an amazing new scientific
version of the Bible."

216
00:13:10,916 --> 00:13:13,817
Eight volumes
in all five biblical languages

217
00:13:13,953 --> 00:13:16,820
and, of course,
copiously illustrated

218
00:13:16,956 --> 00:13:18,753
and costing a fortune.

219
00:13:18,891 --> 00:13:21,758
Plantin's client was so impressed
by the scientific angle,

220
00:13:21,894 --> 00:13:24,658
he promptly ordered a lot
of other sacred books, as well.

221
00:13:24,797 --> 00:13:26,924
40,000 copies.

222
00:13:27,066 --> 00:13:29,296
What a client he was.

223
00:13:34,106 --> 00:13:35,471
Philip II of Spain,

224
00:13:35,608 --> 00:13:38,839
the kind of client
every publisher dreams of.

225
00:13:40,779 --> 00:13:44,271
And how all this got
Henry Hudson to Spitsbergen

226
00:13:44,416 --> 00:13:46,077
has to do
with the scientific spin

227
00:13:46,218 --> 00:13:47,947
Plantin put on his proposition.

228
00:13:48,087 --> 00:13:51,853
This was going to be a Bible,
he said, with a database attached.

229
00:13:51,991 --> 00:13:54,459
Something in the Bible
you wanted to know more about,

230
00:13:54,593 --> 00:13:57,926
here it was in an appendix.

231
00:13:58,063 --> 00:14:00,964
Plantin pulled in experts
to write these appendices:

232
00:14:01,100 --> 00:14:04,536
linguists, zoologists,
historians, draftsmen, bankers,

233
00:14:04,670 --> 00:14:06,831
and of course cartographers

234
00:14:06,972 --> 00:14:09,736
to do the all-important maps
of the Holy Land.

235
00:14:11,076 --> 00:14:12,907
And when they'd done their stuff
for Plantin,

236
00:14:13,045 --> 00:14:15,445
they went out
and set up for themselves.

237
00:14:15,581 --> 00:14:18,141
Caused a kind
of knowledge fallout

238
00:14:18,284 --> 00:14:19,444
that in a way helped to kick off

239
00:14:19,585 --> 00:14:21,985
what we in the modern world
call science.

240
00:14:22,121 --> 00:14:23,952
One of these fallout people

241
00:14:24,089 --> 00:14:26,614
was a Calvinist minister
called Plancius,

242
00:14:26,759 --> 00:14:29,728
who was a pupil
of the great mapmaker Mercator,

243
00:14:29,862 --> 00:14:31,022
who was also published here.

244
00:14:31,163 --> 00:14:35,156
So Plancius was very keen
on things nautical.

245
00:14:35,301 --> 00:14:36,768
And it was Plancius
who persuaded

246
00:14:36,902 --> 00:14:39,803
the Dutch East India Company
to hire Henry Hudson,

247
00:14:39,939 --> 00:14:41,702
and it was Plancius
who thought up

248
00:14:41,840 --> 00:14:43,364
the northerly route to China

249
00:14:43,509 --> 00:14:46,535
that got Henry Hudson nowhere
but Spitsbergen.

250
00:14:50,482 --> 00:14:52,143
And that's how
the printing press

251
00:14:52,284 --> 00:14:54,479
ended up doing
for the poor old whales.

252
00:14:54,620 --> 00:14:56,383
That's history for you.

253
00:14:56,522 --> 00:14:59,184
And remember we got here
from cling wrap.

254
00:14:59,325 --> 00:15:01,190
But why here?

255
00:15:01,327 --> 00:15:04,421
Why did Philip II need
so many holy books?

256
00:15:10,803 --> 00:15:13,533
Because the Catholic church
was in trouble.

257
00:15:13,672 --> 00:15:15,537
In mid-16th century,

258
00:15:15,674 --> 00:15:20,168
Luther was persuading Catholics
to go Protestant in droves.

259
00:15:20,312 --> 00:15:24,339
In 1565, after a top-level meeting,
Rome decided,

260
00:15:24,483 --> 00:15:27,782
one, get the crowds back
with music and decor like this;

261
00:15:27,920 --> 00:15:32,653
two, get people like Plantin
to publish standardized holy texts;

262
00:15:32,791 --> 00:15:35,351
three, start a Jesuit crackdown;

263
00:15:35,494 --> 00:15:40,431
four, discourage free thinking
with a list of prohibited books.

264
00:15:44,703 --> 00:15:46,898
One of the first books on that list

265
00:15:47,039 --> 00:15:49,439
was written by a Pole
called Copernicus,

266
00:15:49,575 --> 00:15:53,341
who reckoned that the Earth
wasn't the center of the universe,

267
00:15:53,479 --> 00:15:55,276
which Rome said it was.

268
00:15:56,982 --> 00:16:00,782
Now, nobody much took
what Copernicus had said seriously

269
00:16:00,919 --> 00:16:05,185
until 1610 when here,
just outside Florence,

270
00:16:05,324 --> 00:16:07,849
an Italian math professor
called Galileo

271
00:16:07,993 --> 00:16:10,427
living in the nearby village of Arcetri

272
00:16:10,562 --> 00:16:13,554
published descriptions
of what he'd seen the previous year

273
00:16:13,699 --> 00:16:15,223
when he'd looked up at the sky

274
00:16:15,367 --> 00:16:17,995
through an amazing
new Dutch gizmo.

275
00:16:31,617 --> 00:16:33,517
It was called a telescope.

276
00:16:33,652 --> 00:16:35,176
Now, being a helpful chap,

277
00:16:35,320 --> 00:16:37,845
Galileo drew pictures
of what he'd seen through it.

278
00:16:37,990 --> 00:16:39,890
Shocking pictures.

279
00:16:40,025 --> 00:16:43,461
I mean, that little circle is Jupiter,

280
00:16:43,595 --> 00:16:46,223
and those little "X"s
on either side of it

281
00:16:46,365 --> 00:16:48,128
are Jupiter's moons.

282
00:16:48,267 --> 00:16:50,701
Now, if the church was right

283
00:16:50,836 --> 00:16:53,566
and the Earth really was
the center of everything,

284
00:16:53,705 --> 00:16:55,502
then what business
had those little moons

285
00:16:55,641 --> 00:16:57,632
going 'round anything else?

286
00:16:57,776 --> 00:17:00,506
Well, that put Galileo's work
on the Pope's hit list right off,

287
00:17:00,646 --> 00:17:02,705
because he was seeing things
in the sky

288
00:17:02,848 --> 00:17:04,907
you weren't supposed to see,

289
00:17:05,050 --> 00:17:08,383
like mountains on the moon
that the church said

290
00:17:08,520 --> 00:17:11,956
was supposed to be a perfect,
featureless heavenly body.

291
00:17:13,659 --> 00:17:15,388
Meanwhile, back on Earth,

292
00:17:15,527 --> 00:17:17,995
what got most ordinary people
all excited

293
00:17:18,130 --> 00:17:19,791
wasn't that theological stuff.

294
00:17:19,932 --> 00:17:22,901
It was the fact that telescopes
had now improved enough

295
00:17:23,035 --> 00:17:25,629
for you to get really good fixes
on stars.

296
00:17:25,771 --> 00:17:27,705
Great news for ships' captains.

297
00:17:27,840 --> 00:17:30,138
Take a star you want to fix on.

298
00:17:30,275 --> 00:17:32,175
Okay, using a good telescope,

299
00:17:32,311 --> 00:17:35,178
you find the angle
that the star is at up in the sky.

300
00:17:35,314 --> 00:17:38,283
Then you look that angle up
in your book of star tables,

301
00:17:38,417 --> 00:17:40,885
and they tell you where on Earth
you have to be

302
00:17:41,019 --> 00:17:44,978
to see the star at that angle
at that time.

303
00:17:45,124 --> 00:17:47,718
Trouble was,
the star tables were based

304
00:17:47,860 --> 00:17:49,987
on the Earth being
a perfect sphere,

305
00:17:50,129 --> 00:17:51,687
but if it wasn't,

306
00:17:51,830 --> 00:17:55,197
you could be miles away
from where you thought you were.

307
00:17:57,503 --> 00:17:59,471
lf the Earth
were a perfect sphere,

308
00:17:59,605 --> 00:18:01,596
a one-degree difference
in a star fix

309
00:18:01,740 --> 00:18:03,435
would be seen
from points on Earth--

310
00:18:03,575 --> 00:18:05,543
let me exaggerate
to make the point--

311
00:18:05,677 --> 00:18:07,372
this far apart.

312
00:18:07,513 --> 00:18:11,779
And wherever you went on Earth,
that distance would be the same.

313
00:18:11,917 --> 00:18:15,250
Well, in 1763,
a bunch of French scientists

314
00:18:15,387 --> 00:18:18,220
took some extremely precise
star fix measurements

315
00:18:18,357 --> 00:18:20,882
up in Lapland to check this out,

316
00:18:21,026 --> 00:18:23,324
and they discovered that the Earth

317
00:18:23,462 --> 00:18:26,590
was a flattened sphere,
because up north,

318
00:18:26,732 --> 00:18:30,065
thanks to the accuracy
with which they did their star fixes,

319
00:18:30,202 --> 00:18:32,636
at precisely the same time
each night,

320
00:18:32,771 --> 00:18:35,137
they found
the one-degree difference here

321
00:18:35,274 --> 00:18:38,004
was a mile longer
than down at the equator.

322
00:18:40,612 --> 00:18:42,546
They managed to do
all that precision work

323
00:18:42,681 --> 00:18:45,980
because they had one of the latest
measuring instruments with them,

324
00:18:46,118 --> 00:18:49,246
which took metalworking
to new heights.

325
00:18:54,893 --> 00:18:58,454
This is the miracle machine:
George Graham's clock.

326
00:18:58,597 --> 00:19:01,225
Most accurate ever built till then

327
00:19:01,366 --> 00:19:04,028
because of the way Graham
had shaped the pallet arms.

328
00:19:04,169 --> 00:19:07,900
That's one moving in and out
of the drive wheel teeth; see?

329
00:19:08,040 --> 00:19:11,066
Its special shape means
it releases the wheel

330
00:19:11,210 --> 00:19:13,178
at a very precise moment.

331
00:19:13,312 --> 00:19:17,408
So since the two pallet arms are
rigidly fixed to the pendulum behind,

332
00:19:17,549 --> 00:19:20,313
the drive wheel is caught and released
by one arm or the other

333
00:19:20,452 --> 00:19:22,647
with every swing
of the pendulum.

334
00:19:28,961 --> 00:19:33,057
Well, that was fine as long
as the drive wheels worked okay,

335
00:19:33,198 --> 00:19:34,688
which they don't always,

336
00:19:34,833 --> 00:19:38,291
especially when they're here,
at the top of a tower...

337
00:19:42,241 --> 00:19:46,302
where the clock can get covered
in bat droppings, old grease,

338
00:19:46,445 --> 00:19:48,606
ice, snow, that kind of gunk,

339
00:19:48,747 --> 00:19:51,045
which everybody knew
was going to be a problem

340
00:19:51,183 --> 00:19:53,048
with this particular clock.

341
00:19:54,286 --> 00:19:57,119
A lawyer called Grimshaw
saved the day.

342
00:19:57,256 --> 00:19:59,690
Here's one of the pallet arms.

343
00:19:59,825 --> 00:20:01,656
Now, instead of being fixed
to the pendulum

344
00:20:01,793 --> 00:20:04,159
like the Graham clock,
it only touches it

345
00:20:04,296 --> 00:20:06,856
via those two horizonal rods
bottom left.

346
00:20:08,934 --> 00:20:11,164
So that lets the pallet arm fall back

347
00:20:11,303 --> 00:20:13,828
to capture the drive wheel
under its own weight,

348
00:20:13,972 --> 00:20:17,874
so there's no fixed connection
to mess things up.

349
00:20:18,010 --> 00:20:22,208
So it's fail safe, which is why
what you're going to hear next

350
00:20:22,347 --> 00:20:25,373
is accurate
to within one fifth of a second.

351
00:20:51,443 --> 00:20:54,003
Well, I expect you know
the clock I was talking about:

352
00:20:54,146 --> 00:20:55,204
this one.

353
00:20:55,347 --> 00:20:57,315
Big Ben
on the Houses of Parliament

354
00:20:57,449 --> 00:20:59,349
thanks to plastic film.

355
00:20:59,484 --> 00:21:03,545
Well, I suppose it's high time
I wrap this one up.

356
00:21:03,689 --> 00:21:04,951
Bye.