0:00:06 > 0:00:10This is the story of how canals changed and shaped our modern world.
0:00:15 > 0:00:18Carrying huge volumes of goods and fuel,
0:00:18 > 0:00:21they were a stimulus to Britain's great Industrial Revolution.
0:00:24 > 0:00:26But they also gave us much, much more
0:00:26 > 0:00:30and their legacy lives on today in surprising ways.
0:00:30 > 0:00:31My name's Liz McIvor
0:00:31 > 0:00:34and I've spent my life studying and talking about history.
0:00:34 > 0:00:37And now I think it's time for us to take a different look
0:00:37 > 0:00:39at our inland waterways.
0:00:42 > 0:00:44Back in the late 1700s,
0:00:44 > 0:00:46carving up our landscape with canals
0:00:46 > 0:00:49brought to light fresh discoveries about the earth below.
0:00:50 > 0:00:52The new waterways gave us clues
0:00:52 > 0:00:55into the mysteries of our planet's creation,
0:00:55 > 0:00:57decades before Darwin's theories took hold.
0:01:00 > 0:01:01So how did this happen?
0:01:01 > 0:01:04How did canal building give us a deeper understanding of the Earth
0:01:04 > 0:01:07and help create the new science of geology?
0:01:23 > 0:01:25Just off London's Piccadilly,
0:01:25 > 0:01:28behind the doorway of the Geological Society
0:01:28 > 0:01:31is a very special and very important document...
0:01:33 > 0:01:37..one which had a profound effect on our economic growth,
0:01:37 > 0:01:40our scientific knowledge and our understanding of our planet.
0:01:40 > 0:01:44And amazingly it's all the work of just one man.
0:01:46 > 0:01:48This map had its origin
0:01:48 > 0:01:52some 100 or so miles to the west of here in Somerset.
0:01:52 > 0:01:54And to understand how it was created,
0:01:54 > 0:01:56and why it's so significant,
0:01:56 > 0:01:59we need to return to a time when canals were being carved
0:01:59 > 0:02:01through the British landscape.
0:02:05 > 0:02:09This is the Kennet and Avon, 87 miles long
0:02:09 > 0:02:12and one of the jewels of Britain's canal network.
0:02:13 > 0:02:16Getting this canal built was a seriously tough challenge
0:02:16 > 0:02:19and it was partly down to the fact that geological knowledge
0:02:19 > 0:02:21was so limited at the time.
0:02:23 > 0:02:25The canal was given the go-ahead
0:02:25 > 0:02:28during the period of frenzied building in the 1790s
0:02:28 > 0:02:30known as Canal Mania.
0:02:30 > 0:02:33By linking the Kennet navigation at Newbury with the Avon at Bath,
0:02:33 > 0:02:37it would open up a route between London and Bristol.
0:02:37 > 0:02:40Horse-drawn barges would be able to get between the cities
0:02:40 > 0:02:42in just ten days,
0:02:42 > 0:02:45potentially halving the transport costs by road.
0:02:47 > 0:02:49The man hired to plot the route
0:02:49 > 0:02:51and oversee construction of the new canal
0:02:51 > 0:02:54was a rising star of civil engineering,
0:02:54 > 0:02:56the Scotsman John Rennie.
0:02:56 > 0:02:59However, he only had limited experience of canal building.
0:03:03 > 0:03:07Construction work got under way in October 1794
0:03:07 > 0:03:10when the first sod was cut at Bradford on Avon,
0:03:10 > 0:03:12six miles to the east of Bath.
0:03:16 > 0:03:20In time, the wharves here would handle the canal's main cargoes -
0:03:20 > 0:03:22coal, grain and Bath stone.
0:03:25 > 0:03:28The stretch of canal from Bradford on Avon to Bath
0:03:28 > 0:03:31provides a fantastic location for pleasure boaters today.
0:03:31 > 0:03:34But for John Rennie and his construction teams in the 1790s,
0:03:34 > 0:03:37the local landscape proved a major headache.
0:03:39 > 0:03:41Geologist Dr Janet Sumner
0:03:41 > 0:03:44understands all about the treacherous lie of the land
0:03:44 > 0:03:46in this part of the world.
0:03:46 > 0:03:49The rocks in this area consist of limestone,
0:03:49 > 0:03:52which was laid down in shallow tropical seas,
0:03:52 > 0:03:56sandstone and layers of shale and mud.
0:03:56 > 0:03:59Now the sandstone and the limestone are really hard,
0:03:59 > 0:04:01but permeable rocks,
0:04:01 > 0:04:04which wouldn't be a problem but for the layers of mud.
0:04:04 > 0:04:08And what happens is one particular layer that they call fuller's earth,
0:04:08 > 0:04:10which is a type of clay,
0:04:10 > 0:04:12when the water reached the fuller's earth layer,
0:04:12 > 0:04:15it couldn't get through, it was impermeable.
0:04:15 > 0:04:18So it waterlogged the clay and it turned it into something
0:04:18 > 0:04:21with the consistency of, like, tomato ketchup,
0:04:21 > 0:04:25which meant that the overlying layers of sandstone and limestone
0:04:25 > 0:04:27simply used it as a lubricant
0:04:27 > 0:04:30and just slid down into the cutting
0:04:30 > 0:04:32in a series of huge landslides.
0:04:32 > 0:04:34What kind of damage are we talking about?
0:04:34 > 0:04:37Well, in terms of scale, you know,
0:04:37 > 0:04:41there's an estimate the equivalent of an area of seven football pitches
0:04:41 > 0:04:45came sliding down the side into the canal cuts.
0:04:45 > 0:04:47And that meant that on this stretch,
0:04:47 > 0:04:50parts of the canal had to be repeatedly drained
0:04:50 > 0:04:52and then shored up with planks.
0:04:53 > 0:04:57The damage caused by the area's unstable geology
0:04:57 > 0:04:59had big cost implications for the canal.
0:04:59 > 0:05:03In 1800, Rennie reported that the landslips and other expenses
0:05:03 > 0:05:07would add more than £270,000 to the bill.
0:05:09 > 0:05:13With the science of geology still very much in its infancy,
0:05:13 > 0:05:17early canal engineers like Rennie really were flying blind.
0:05:17 > 0:05:19The basic problem that they had, Liz,
0:05:19 > 0:05:22was they didn't have a geological map.
0:05:22 > 0:05:25They had no idea about the different types of rocks
0:05:25 > 0:05:27and how the rocks were lying.
0:05:27 > 0:05:29And they really needed a map, but they hadn't got one.
0:05:29 > 0:05:32All they'd got was information from things like boreholes,
0:05:32 > 0:05:35which, in some cases, were miles apart.
0:05:35 > 0:05:38So they knew nothing about the geology in between.
0:05:38 > 0:05:41So the canal building crews
0:05:41 > 0:05:44frequently encountered problems like the landslips,
0:05:44 > 0:05:46natural springs, you know,
0:05:46 > 0:05:48hitting hard rock that needed blasting,
0:05:48 > 0:05:52having to dig tunnels that they thought, perhaps, would have been through earth
0:05:52 > 0:05:55and then finding out they were chipping through solid rock.
0:05:55 > 0:05:57So there were lots of problems like that that, you know,
0:05:57 > 0:06:00all added time and expense to the bill.
0:06:03 > 0:06:05- Bye.- See you.
0:06:05 > 0:06:07In spite of the challenges of the landscape,
0:06:07 > 0:06:10Rennie and his teams of navvies forged on
0:06:10 > 0:06:12and the Kennet and Avon began to take shape.
0:06:12 > 0:06:15But more geological problems lay in wait.
0:06:17 > 0:06:19To the west of Bradford,
0:06:19 > 0:06:22Rennie constructed an impressive aqueduct at Avoncliff.
0:06:22 > 0:06:25But it was blighted by poor construction materials.
0:06:28 > 0:06:30John Rennie wanted to build the aqueduct in brick,
0:06:30 > 0:06:35but the canal company overruled him and insisted on Bath stone.
0:06:35 > 0:06:38They wanted local quarry owners to feel obliged to use the canal
0:06:38 > 0:06:40to transport their goods.
0:06:40 > 0:06:43But Rennie later regretted not putting his foot down.
0:06:43 > 0:06:47Bath stone looks lovely, but it becomes easily frost-damaged
0:06:47 > 0:06:49if not properly treated after quarrying.
0:06:51 > 0:06:54As soon as the aqueduct was completed in 1801,
0:06:54 > 0:06:57its central arch started sagging
0:06:57 > 0:07:00and not surprisingly the whole structure has had to be repaired
0:07:00 > 0:07:02many times over the years,
0:07:02 > 0:07:05with bricks helping to sure up the damaged stone.
0:07:05 > 0:07:09All these problems started taking their toll
0:07:09 > 0:07:12and Rennie's canal dream threatened to turn into a nightmare.
0:07:12 > 0:07:15But was his luck about to change for the better?
0:07:16 > 0:07:19The truth of the matter was that the early canal builders
0:07:19 > 0:07:22had very little clue about what they would encounter
0:07:22 > 0:07:24when digging the trenches and tunnels.
0:07:24 > 0:07:26A lot was left to chance.
0:07:26 > 0:07:28Sometimes it would be slips and leaks,
0:07:28 > 0:07:30but at other times they'd get lucky
0:07:30 > 0:07:33and a fluke of geology would lend a helping hand.
0:07:33 > 0:07:36And that's exactly what happened here at Caen Hill,
0:07:36 > 0:07:39just outside the important trading centre of Devizes.
0:07:45 > 0:07:47For the canal to climb the hill,
0:07:47 > 0:07:49Rennie planned a series of 29 locks
0:07:49 > 0:07:52and the dramatic central section of these
0:07:52 > 0:07:54is one of the steepest flights on the whole canal network.
0:07:58 > 0:08:00The reason that the locks are here
0:08:00 > 0:08:03is because here you're climbing up the greensand,
0:08:03 > 0:08:06up to the level of Salisbury Plain
0:08:06 > 0:08:08and then the chalklands beyond.
0:08:08 > 0:08:11And that's why there's such a steep flight.
0:08:13 > 0:08:15Because of Caen Hill's steepness,
0:08:15 > 0:08:18there wasn't space to use the normal arrangements of water chambers
0:08:18 > 0:08:20between the locks.
0:08:20 > 0:08:23So Rennie had to build unusually large side ponds
0:08:23 > 0:08:26to replenish the water in each lock after use.
0:08:27 > 0:08:29Unlike on the Bradford stretch,
0:08:29 > 0:08:32this time fortune favoured the bold
0:08:32 > 0:08:34and the canal builders had a stroke of good geological luck.
0:08:36 > 0:08:38They were building the canal
0:08:38 > 0:08:40and halfway up on the right-hand side they found clay,
0:08:40 > 0:08:43gault clay, which is absolutely fantastic for brickmaking.
0:08:43 > 0:08:46They'd hit a real problem with the canal
0:08:46 > 0:08:49because lots of the locks were built of stone.
0:08:49 > 0:08:51But that was suffering very badly from frost.
0:08:51 > 0:08:53So they switched to bricks,
0:08:53 > 0:08:56they established a brickworks just up there on the right-hand side.
0:08:56 > 0:08:58And it was a major undertaking,
0:08:58 > 0:09:02because not only were they using bricks in the flight of locks that you can see,
0:09:02 > 0:09:05but also, 15 miles to the east,
0:09:05 > 0:09:07they were building a tunnel called the Bruce Tunnel.
0:09:07 > 0:09:11The landowner, the Earl of Aylesbury, he was happy for the canal to go through,
0:09:11 > 0:09:14but he didn't want to be able to see it, so they had to build a tunnel
0:09:14 > 0:09:17and they used over two million bricks in its construction.
0:09:17 > 0:09:19It's absolutely incredible.
0:09:19 > 0:09:21And it's an incredibly expensive way
0:09:21 > 0:09:23- to hide a piece of engineering, isn't it?- Absolutely.
0:09:23 > 0:09:27- It was very much a case of not in my backyard, wasn't it?- Absolutely. Nothing changes!
0:09:27 > 0:09:29How long were the brickworks open for?
0:09:29 > 0:09:31It was actually open into the 1960s
0:09:31 > 0:09:34and there were still people around who worked there.
0:09:34 > 0:09:36Of course, it's left its legacy throughout Devizes
0:09:36 > 0:09:40with the handmade bricks that are still in many buildings in the town today.
0:09:42 > 0:09:46The clay bricks were a big help in getting the canal up Caen Hill
0:09:46 > 0:09:49and then under the Earl of Aylesbury's estate.
0:09:49 > 0:09:52But Rennie encountered another problem further to the east
0:09:52 > 0:09:55at Crofton, the Kennet and Avon's highest point.
0:09:55 > 0:09:59There was no natural water supply to feed the summit of the canal
0:09:59 > 0:10:03and it looked as if another expensive tunnel would be required.
0:10:03 > 0:10:06But, instead, Rennie decided to use a huge pump
0:10:06 > 0:10:09to keep the canal topped up.
0:10:09 > 0:10:12We're going through limestone here, quite different to Caen Hill.
0:10:12 > 0:10:15He had a geological challenge here -
0:10:15 > 0:10:18how to get water to the top level where the rock is porous
0:10:18 > 0:10:21and there was no natural supply up there.
0:10:21 > 0:10:23And behind us over here is the pumping station,
0:10:23 > 0:10:26where the oldest beam engine in the world,
0:10:26 > 0:10:28the Boulton and Watt beam engine,
0:10:28 > 0:10:30draws water up in this gigantic piston.
0:10:30 > 0:10:34Each draw draws one tonne of water each time it rotates.
0:10:34 > 0:10:37And that lifts water just under 50 foot up
0:10:37 > 0:10:39to the highest point in the canal.
0:10:39 > 0:10:42The steam-powered pump could keep the summit topped up,
0:10:42 > 0:10:46but it still needed to be fed by a water supply at its base.
0:10:46 > 0:10:48Once again, though, Rennie struck lucky,
0:10:48 > 0:10:52this time by finding some springs nearby.
0:10:52 > 0:10:56The canal didn't supply enough water for what he needed on its own,
0:10:56 > 0:11:00because you've got to keep the canal in water, as well as taking water out of it.
0:11:00 > 0:11:01So he then built a reservoir
0:11:01 > 0:11:03and the springs fed the reservoir
0:11:03 > 0:11:07and that provided sufficient backup volume of water
0:11:07 > 0:11:09to keep the whole system working.
0:11:09 > 0:11:12The Crofton Pumping Station was completed in 1809,
0:11:12 > 0:11:16allowing the Kennet and Avon Canal to open for business the following year.
0:11:20 > 0:11:25Rennie may have found solutions to all the engineering challenges the landscape had posed,
0:11:25 > 0:11:29but the Kennet and Avon had still taken 16 years to complete
0:11:29 > 0:11:33at a final cost of almost £1 million,
0:11:33 > 0:11:36more than four times its original estimate.
0:11:38 > 0:11:42But even though geology presented canal builders with major stumbling blocks,
0:11:42 > 0:11:45it's worth remembering that some canals were only ever built
0:11:45 > 0:11:49because of the local geology and the minerals to be found within the landscape.
0:11:51 > 0:11:53100 miles to the north of Bath,
0:11:53 > 0:11:56the Dudley Canal Tunnel in the West Midlands Black Country
0:11:56 > 0:12:00is a labyrinth of over three miles of underground passageways.
0:12:00 > 0:12:03They were carved out in the 1770s
0:12:03 > 0:12:06to transport limestone which was being mined
0:12:06 > 0:12:09to feed the new blast furnaces of the Industrial Revolution.
0:12:09 > 0:12:14The canal linked the mines to the wider national waterways network.
0:12:14 > 0:12:17Limestone was a really useful rock.
0:12:17 > 0:12:19It was used as a flux for smelting iron,
0:12:19 > 0:12:21which made the iron a lot purer.
0:12:21 > 0:12:24It was used for agricultural reasons - they used to spread it on fields.
0:12:24 > 0:12:26It was also turned into quicklime
0:12:26 > 0:12:29and put into things like lime mortar, which created a waterproof mortar
0:12:29 > 0:12:32that they could use in building canals, in fact.
0:12:32 > 0:12:34There were lots of uses for limestone,
0:12:34 > 0:12:36which made it one of the key ingredients, really,
0:12:36 > 0:12:39of the Industrial Revolution.
0:12:39 > 0:12:41Exploiting the limestone rock seams
0:12:41 > 0:12:43may have been the whole purpose of the Dudley Canal.
0:12:43 > 0:12:46But, as with many other canals of the era,
0:12:46 > 0:12:49patchy geological knowledge left construction teams
0:12:49 > 0:12:50literally stumbling in the dark.
0:12:52 > 0:12:55The construction of the tunnel was long and laborious,
0:12:55 > 0:12:57a very difficult job.
0:12:57 > 0:13:01It involved digging out the rock with hand tools, pickaxes, things like that.
0:13:01 > 0:13:05They constructed the tunnel by sinking construction shafts down from the surface
0:13:05 > 0:13:06and then when they got to the bottom,
0:13:06 > 0:13:09went out in two directions with miners going each way.
0:13:09 > 0:13:12And then they met up, hopefully, some times better than others.
0:13:12 > 0:13:15There's a few kinks in the tunnel where they didn't quite get it right.
0:13:15 > 0:13:18And, of course, they were digging through completely foreign geology.
0:13:18 > 0:13:20They had no idea what they were going to encounter.
0:13:20 > 0:13:23As well as the limestone which was what they were looking for,
0:13:23 > 0:13:26there are various volcanic rocks down under here,
0:13:26 > 0:13:28mud, shales, all sorts of things
0:13:28 > 0:13:31that meant that the terrain for them underground was very variable
0:13:31 > 0:13:33and they could go from a very soft rock one minute
0:13:33 > 0:13:36to a very hard, difficult rock the next.
0:13:36 > 0:13:40'Right, now the tunnel we're going into is the second longest...'
0:13:44 > 0:13:46Despite these geological challenges,
0:13:46 > 0:13:49the canal tunnel became a big success once it was built.
0:13:49 > 0:13:52In 1853 alone,
0:13:52 > 0:13:55more than 41,000 boats carried limestone
0:13:55 > 0:13:58through these tunnels from the caves.
0:13:58 > 0:14:01At its height, these mines would have been absolutely packed with people,
0:14:01 > 0:14:04miners at the rock faces digging away the limestone,
0:14:04 > 0:14:06others loading the boats.
0:14:06 > 0:14:10You were talking about ten boats an hour running through the tunnel,
0:14:10 > 0:14:12so it would have been really busy,
0:14:12 > 0:14:14sort of like the motorway of its time.
0:14:14 > 0:14:17'Good morning. Look to the left and we have...'
0:14:17 > 0:14:20The Dudley Canal Tunnel may have been a triumph,
0:14:20 > 0:14:24but other canals were nearly ruined by unexpected geological problems.
0:14:24 > 0:14:27It took eight years and three attempts
0:14:27 > 0:14:30to complete the Blisworth Tunnel in Northamptonshire.
0:14:30 > 0:14:33Test boreholes failed to detect a dip in the strata
0:14:33 > 0:14:36that created an underground reservoir, causing serious flooding.
0:14:38 > 0:14:41And navvies on the Harecastle Tunnel in Staffordshire
0:14:41 > 0:14:44spent nine long years inching slowly through everything
0:14:44 > 0:14:47from hard granite and millstone grit
0:14:47 > 0:14:49to treacherous quicksand.
0:14:49 > 0:14:52The fact that the early canal engineers
0:14:52 > 0:14:56had such a basic grasp of geology was a big drawback.
0:14:56 > 0:15:00But one canal man was about to unlock the secrets of the rocks beneath our feet.
0:15:00 > 0:15:02Secrets which would, in time,
0:15:02 > 0:15:05transform our entire understanding of the planet.
0:15:07 > 0:15:10William Smith was the son of an Oxfordshire village blacksmith,
0:15:10 > 0:15:13who taught himself surveying as a teenager.
0:15:13 > 0:15:16He may have come from humble beginnings,
0:15:16 > 0:15:18with limited formal education,
0:15:18 > 0:15:21but he had a real knack for reading the landscape.
0:15:21 > 0:15:24In 1793, whilst still in his early '20s,
0:15:24 > 0:15:27he was hired by the Kennet and Avon's engineer, John Rennie,
0:15:27 > 0:15:30to work as the surveyor for a new waterway
0:15:30 > 0:15:33linking the main canal to a fresh coalfield in Somerset.
0:15:40 > 0:15:42This is the Dundas Aqueduct.
0:15:44 > 0:15:46And it's over there at the Dundas Basin
0:15:46 > 0:15:49where the Somersetshire Coal Canal joins the Kennet and Avon,
0:15:49 > 0:15:52particularly important because coal made up the lion's share
0:15:52 > 0:15:55of the Kennet and Avon's traffic.
0:15:57 > 0:16:00The Coal Canal has been long abandoned
0:16:00 > 0:16:02and parts have been redeveloped and filled in.
0:16:02 > 0:16:06Much of the course of the canal can still be traced, though,
0:16:06 > 0:16:10and this is the route that William Smith devised back in 1794.
0:16:10 > 0:16:15Professor Hugh Torrens is one of the world's leading experts on Smith's life
0:16:15 > 0:16:18and first explored the landscape around Bath
0:16:18 > 0:16:21as an undergraduate geologist in the 1950s.
0:16:21 > 0:16:24Is this the type of thing that William Smith would have used to survey
0:16:24 > 0:16:27- the Somersetshire Coal Canal? - Yes. A theodolite.
0:16:27 > 0:16:31It's a horizontometer trying to measure exact horizontality.
0:16:31 > 0:16:34This is a later model of the sort of thing that was standard fare,
0:16:34 > 0:16:37beautifully made, beautifully adjustable,
0:16:37 > 0:16:38fantastic piece of equipment.
0:16:38 > 0:16:40And, of course, the crucial thing about canals
0:16:40 > 0:16:43with this wonderful series of locks we're going through
0:16:43 > 0:16:45is that you can't make water run uphill or downhill.
0:16:45 > 0:16:48You have to have it absolutely horizontal,
0:16:48 > 0:16:51though it was a very interesting early experiment for Smith.
0:16:51 > 0:16:54He was a land surveyor and I think was very good at, basically,
0:16:54 > 0:16:56the lie of the land.
0:16:56 > 0:17:00They plotted the entire topography of this beautiful part of the world,
0:17:00 > 0:17:01most of it would have been on foot,
0:17:01 > 0:17:03just walking, walking,
0:17:03 > 0:17:06measuring, measuring, surveying, surveying,
0:17:06 > 0:17:09with an assistant to check the other end was at horizontal...
0:17:09 > 0:17:13measurement, you need somebody to hold a board up or a site up.
0:17:13 > 0:17:16And, I think, the fact that these locks are built so beautifully
0:17:16 > 0:17:18is a proof of their achievement.
0:17:18 > 0:17:22The excavation of the Coal Canal from 1795
0:17:22 > 0:17:26gave Smith an opportunity to test theories about rock strata
0:17:26 > 0:17:29that he'd been developing while looking at coal seams.
0:17:29 > 0:17:33By cutting open a long slice of the Somerset countryside,
0:17:33 > 0:17:38he would be able to see exactly how layers of rock were lying underneath the ground.
0:17:38 > 0:17:42He realised that there was an order of the strata that the rocks were in.
0:17:42 > 0:17:45This is a clay unit we're in here, above it's a limestone,
0:17:45 > 0:17:48and so you can put them in an order or a sequence.
0:17:48 > 0:17:51And when he was asked by people what he'd discovered
0:17:51 > 0:17:54and trying to get across the complexity of geology, a new science,
0:17:54 > 0:17:56he used the analogy of bread and butter.
0:17:56 > 0:17:58He used to get a pile of bread, slice it up,
0:17:58 > 0:18:01then put them in layers and tip them over and say,
0:18:01 > 0:18:04"This is what the rock strata are like and it's the same with geology."
0:18:04 > 0:18:05And in his ordering of strata,
0:18:05 > 0:18:10he actually alphabetised 22 rocks in the Bath area.
0:18:10 > 0:18:13The top one was the chalk, the bottom one was the coal.
0:18:13 > 0:18:16Where would we be indexing books or knowledge without an alphabet?
0:18:16 > 0:18:20Knowing where letter A is, and how letter L relates to it?
0:18:20 > 0:18:22For the first time in English history,
0:18:22 > 0:18:24and probably other countries' history,
0:18:24 > 0:18:27it was the first time the rocks had been ordered.
0:18:33 > 0:18:35It's really atmospheric, isn't it,
0:18:35 > 0:18:37to be able to walk through this old canal
0:18:37 > 0:18:40and look at the weathering and the damage to the stonework?
0:18:40 > 0:18:44Yes, one forgets how intense the building of the thing was.
0:18:44 > 0:18:46You have the remains of the lock gates here.
0:18:46 > 0:18:50These big oak doors and the pins, wrought iron pins to prove it.
0:18:50 > 0:18:54And this is...210 years since it was opened in 1805,
0:18:54 > 0:18:57so it's an incredible achievement.
0:18:57 > 0:19:00As well as showing Smith how the rock layers were ordered,
0:19:00 > 0:19:04building the Coal Canal gave him an opportunity to gather fossil specimens,
0:19:04 > 0:19:09which he realised were the key to identifying exactly which strata rocks were part of.
0:19:10 > 0:19:13The important thing about the rocks are - these are Bath Oolite, Great Oolite -
0:19:13 > 0:19:15these rocks have fossils in them and, of course,
0:19:15 > 0:19:18he was collecting fossils all the time he was building the canal.
0:19:18 > 0:19:21And as you go up and down the rock strata,
0:19:21 > 0:19:23you see some are rich in fossils, some are not rich in fossils.
0:19:23 > 0:19:26But it means as soon as you find a fossil,
0:19:26 > 0:19:28you can place it in your sequential order
0:19:28 > 0:19:31and identify the stratum that you've reached.
0:19:31 > 0:19:35The fossils that Smith unearthed while the Coal Canal was being dug
0:19:35 > 0:19:38can still be seen at the Natural History Museum in London.
0:19:39 > 0:19:43The fossils are kept in the order of strata
0:19:43 > 0:19:45in which William Smith kept them
0:19:45 > 0:19:48and displayed them in his home in the Strand.
0:19:48 > 0:19:50He would invite people to come and see them.
0:19:50 > 0:19:53He would even order other people's collections
0:19:53 > 0:19:56because people had been collecting fossils for a long time,
0:19:56 > 0:19:58but they didn't realise their significance.
0:19:58 > 0:20:02He would put them in the natural order in which they occurred and say,
0:20:02 > 0:20:05"Well, these ones are younger and these ones are older
0:20:05 > 0:20:07"and this is how you should arrange them,
0:20:07 > 0:20:10"because this is how they'll be useful."
0:20:10 > 0:20:12Smith was a highly practical man
0:20:12 > 0:20:16and the main application of his discoveries about strata and their fossils
0:20:16 > 0:20:21was to predict the location of mineral wealth under the ground.
0:20:21 > 0:20:24He was able to advise landowners
0:20:24 > 0:20:28what the likelihood of finding coal on their land was.
0:20:28 > 0:20:33People had wasted huge amounts of money thinking that they would be close to coal,
0:20:33 > 0:20:38but William Smith could identify that this was the Oxford Clay,
0:20:38 > 0:20:42for example, and they had no chance of finding coal on their land.
0:20:43 > 0:20:47Crucially, if Smith hadn't been working as a canal surveyor,
0:20:47 > 0:20:50he wouldn't have had the opportunity to properly test
0:20:50 > 0:20:53and develop his theories of strata.
0:20:53 > 0:20:55There's a lot of guesswork in geology.
0:20:55 > 0:20:59When you actually have a cutting like they did for the canal,
0:20:59 > 0:21:02you have the evidence in front of you...
0:21:02 > 0:21:03The different strata,
0:21:03 > 0:21:08their lithology and their fossils are there before your eyes.
0:21:08 > 0:21:09You might think, well,
0:21:09 > 0:21:13"I wonder if this layer of rock is outcropping over there."
0:21:13 > 0:21:15But until you have the cutting, you don't know for sure.
0:21:15 > 0:21:19And he had a beautiful cutting all along the length of the Somerset Coal Canal.
0:21:20 > 0:21:24Smith's ground-breaking table of the rock strata around Bath
0:21:24 > 0:21:27and their fossils was written down in 1799,
0:21:27 > 0:21:31giving birth to the area of geology known as stratigraphy.
0:21:32 > 0:21:35His discoveries are commemorated in Jerry Ortman's
0:21:35 > 0:21:37stone column sculpture,
0:21:37 > 0:21:40located near the ruins of the Coal Canal.
0:21:40 > 0:21:43It features the same types of rocks that Smith first sequenced
0:21:43 > 0:21:45over 200 years ago.
0:21:46 > 0:21:49So, Hugh, what was it about the West Country landscape
0:21:49 > 0:21:52that was particularly important for Smith's discoverers?
0:21:52 > 0:21:55I think the first point is that Bath was a social centre.
0:21:55 > 0:21:59If you wanted to come to find a mistress, take drugs, alcohol,
0:21:59 > 0:22:02relax, you know, all the features of a modern holiday,
0:22:02 > 0:22:04Bath was the social scene.
0:22:04 > 0:22:06Which meant that if you had a discovery,
0:22:06 > 0:22:08it was a good place to try and publicise it.
0:22:08 > 0:22:11Bath is a wonderful place to start geology
0:22:11 > 0:22:14because you can see, as you go round,
0:22:14 > 0:22:17that the top is very nicely horizontal,
0:22:17 > 0:22:19but the valleys are deeply incised.
0:22:19 > 0:22:20So just wandering around you can see
0:22:20 > 0:22:24that there's going to be a possibility of seeing things above and below.
0:22:24 > 0:22:27And this ordering of the strata around Bath, 1799,
0:22:27 > 0:22:29is a really rather crucial document.
0:22:29 > 0:22:33And he said, "People say that I have produced the birth of a new science.
0:22:33 > 0:22:37"If I have, I'd like to claim that Bath was its cradle,"
0:22:37 > 0:22:40which is a rather nice way of saying that if it hadn't been a Bath,
0:22:40 > 0:22:43he wouldn't have been able to do what was done, cos it wouldn't have been possible.
0:22:43 > 0:22:48You have to come to a place like this to see the rocks staring you literally in the face.
0:22:48 > 0:22:52Smith's discoveries earned the nickname of Strata Smith
0:22:52 > 0:22:55and he spent many years in the early 19th century
0:22:55 > 0:22:58continuing to study rock layers and their fossils,
0:22:58 > 0:23:03while working all over Britain as a mineral surveyor and drainage engineer.
0:23:03 > 0:23:06In 1815, he put all his findings together
0:23:06 > 0:23:09and produced something of colossal importance -
0:23:09 > 0:23:13the world's very first national geological map,
0:23:13 > 0:23:15now celebrating its 200th birthday.
0:23:17 > 0:23:19It took him 15 years on his own,
0:23:19 > 0:23:21tramping all over the British Isles,
0:23:21 > 0:23:23to create a picture,
0:23:23 > 0:23:26not just of the pastures and the meadows and the mountains,
0:23:26 > 0:23:28but the hidden underneath,
0:23:28 > 0:23:33the subterranean marvels of the complexity of England and Wales.
0:23:33 > 0:23:37The thing about this map which makes it so extraordinary is that,
0:23:37 > 0:23:39from looking at that,
0:23:39 > 0:23:41you can predict where things are...underneath.
0:23:41 > 0:23:44Previously, if you were mining coal,
0:23:44 > 0:23:46you only did so where it appeared at the ground.
0:23:46 > 0:23:49Smith was able to say, from looking at the dip of the coal
0:23:49 > 0:23:51and where it was likely to be underground,
0:23:51 > 0:23:54that, you could say, at this point,
0:23:54 > 0:23:56under Sheffield, say,
0:23:56 > 0:24:00"I predict that 4,500 feet below me will be coal."
0:24:00 > 0:24:04And so they dug a hole and indeed coal was found.
0:24:04 > 0:24:07And so the whole British mining industry
0:24:07 > 0:24:10was created on the basis of geological maps like this.
0:24:10 > 0:24:15So whenever any mineral resource is found anywhere in the world,
0:24:15 > 0:24:17underground,
0:24:17 > 0:24:19be it oil or be it uranium
0:24:19 > 0:24:21or be it platinum,
0:24:21 > 0:24:24we owe an enormous debt to this map and this man,
0:24:24 > 0:24:26because, more than anything,
0:24:26 > 0:24:30this man enabled us to predict where the treasures of the world will be.
0:24:32 > 0:24:36Smith's work also had a big influence on later thinkers,
0:24:36 > 0:24:38including Charles Darwin.
0:24:38 > 0:24:41He began this map in 1800 effectively,
0:24:41 > 0:24:48when the common belief was that the Earth was only 6,000 years old,
0:24:48 > 0:24:51but Smith said, "This isn't possible.
0:24:51 > 0:24:55"I mean, these creatures that I'm finding in the walls of the canals that I'm digging
0:24:55 > 0:24:59"are evidence that the world is hugely older than that."
0:24:59 > 0:25:02And that the variation within, let's say,
0:25:02 > 0:25:06a particular type of brachiopod or a particular type of ammonite
0:25:06 > 0:25:08was such that it triggered in Darwin,
0:25:08 > 0:25:11what, 50 years later when he was doing his work,
0:25:11 > 0:25:14that variation that led to natural selection
0:25:14 > 0:25:18which led to his book in 1859, The Origin Of The Species.
0:25:18 > 0:25:22That, essentially, Darwin's theories, and discoveries
0:25:22 > 0:25:25were rooted in what Smith discovered.
0:25:26 > 0:25:31Smith's 1850 map was an extraordinary feat for a single individual,
0:25:31 > 0:25:34but he endured some rocky patches in his personal life.
0:25:34 > 0:25:37Poor budgeting and bad business decisions
0:25:37 > 0:25:40left his finances in a precarious state.
0:25:40 > 0:25:44And when the sales of his map were damaged by plagiarised rivals,
0:25:44 > 0:25:46he was pushed into financial ruin.
0:25:46 > 0:25:49He lost his house and ended up in a debtors' prison.
0:25:51 > 0:25:56Gradually, though, his achievements began to gain more official recognition.
0:25:56 > 0:26:00The Geological Society, who initially turned their noses up at this interloper,
0:26:00 > 0:26:04born with limited education and no family connections,
0:26:04 > 0:26:08awarded Smith an honorary medal in 1831.
0:26:08 > 0:26:12Eventually, he was able to retire to Yorkshire on a government pension.
0:26:12 > 0:26:14He died in 1839.
0:26:14 > 0:26:18Not for nothing is William Smith called the father
0:26:18 > 0:26:22of not just English geology, but the father of world geology.
0:26:22 > 0:26:25I think he's a remarkable, remarkable figure,
0:26:25 > 0:26:29and a terrible tragedy, I think, that he's so unsung.
0:26:29 > 0:26:32He should be more famous than Brunel.
0:26:32 > 0:26:36Brunel just built ships. Give this guy a break!
0:26:36 > 0:26:38And perhaps one day he will be.
0:26:38 > 0:26:41The discoverers of men like Smith certainly gave a big boost
0:26:41 > 0:26:43to the youthful science of geology.
0:26:43 > 0:26:46And throughout the 19th century, there was a growing interest
0:26:46 > 0:26:51from specialists and the British public in rocks and fossils.
0:26:51 > 0:26:53The Dudley Canal and its limestone mines
0:26:53 > 0:26:58became one of the nation's most geologically significant sites.
0:26:58 > 0:27:00The rocks here are 420 million years old.
0:27:00 > 0:27:03They're from the Silurian period.
0:27:03 > 0:27:05They formed on a shallow seabed.
0:27:05 > 0:27:09That means that the rocks that we've got are absolutely full of fossils.
0:27:09 > 0:27:12There are thousands of different species here.
0:27:12 > 0:27:16There's a particular type of trilobite that's even known as the Dudley Bug,
0:27:16 > 0:27:18because it's found so much around here,
0:27:18 > 0:27:22that it's sort of become synonymous with the area.
0:27:22 > 0:27:25By the mid-19th century, the canal tunnel
0:27:25 > 0:27:28had gained an international reputation for its geology.
0:27:28 > 0:27:32Because what they found in here was so interesting and so unique,
0:27:32 > 0:27:35it became a very interesting place for geologists to come and study.
0:27:37 > 0:27:39Amongst the mining that was still going on,
0:27:39 > 0:27:42you'd get, sort of, pleasure cruises almost,
0:27:42 > 0:27:45of interested scientists, philosophers, engineers
0:27:45 > 0:27:48who would come and look at the marvel that was underground here.
0:27:48 > 0:27:51The massive caverns that had been taken out
0:27:51 > 0:27:53almost became a bit of a tourist attraction
0:27:53 > 0:27:57for the scientists who were interested in this new science of geology.
0:28:00 > 0:28:03Geological forces produce the mineral riches
0:28:03 > 0:28:07that drove much of the activity during the Industrial Revolution.
0:28:07 > 0:28:10And it was no accident that the science of geology
0:28:10 > 0:28:13took great strides forward at the same time that canal men
0:28:13 > 0:28:16like John Rennie and William Smith
0:28:16 > 0:28:19were grappling with geological challenges.
0:28:20 > 0:28:25It's amazing to think that the canal age didn't just shape the visible landscape around us,
0:28:25 > 0:28:27it helped us to gain a deeper understanding
0:28:27 > 0:28:30of what lies beneath our feet
0:28:30 > 0:28:33and a great debt is owed to canal pioneers like William Smith.