The Elizabethan Blast Furnace Hidden Under A Cottage | Time Team | Timeline

hi everybody and welcome to this documentary on timeline my name is dan snow and i want to tell you about history hit tv it's like the netflix for history hundreds of exclusive documentaries and interviews with the world's best historians we've got an exclusive offer available to fans of timeline if you go to history hit tv you can either follow the information below this video or just google history hit tv and use the code timeline you get a special introductory offer go and check it out in the meantime enjoy this video [Music] this is the churnit valley in staffordshire and we're here on unfinished business a few weeks ago on the time team big dig the people who owned furnace cottage down there put a test bit in their front garden they were looking for the structure that gave the cottage its name an elizabethan blast furnace built in the same year that shakespeare wrote richard iii they didn't find the furnace but they did find this it looks like bloomery slag evidence of a much earlier form of iron making and it was found among a scatter of medieval pottery so it looks like someone was making iron down there hundreds of years before the blast furnace was built this test pit dug by the owners in just one day took the story of furnace cottage back 700 years and opened up the possibility of a huge and revolutionary industry in this valley now we're back with the whole team and three days i think we can build on that don't you [Music] three weeks after the big dig descended on this quiet corner of staffordshire to search for one furnace time team returns to furnace cottage to hunt for two one elizabethan one medieval that's a lot to hide under one small lawn i'm not quite sure why we're geofitting the garden though i'd have thought it's just a small area isn't it really you take up the whole thing john hi why are you bothering to do here well it is really small but i mean we've got some positive results oh that's nice i mean that's where the test pit is here and look at this anomaly really big response from this sort of area and then what looks to be a sort of channel feeding off down to the stream what does that imply to you david well that looks to me that that could well be the corner of the furnace and yes this channel down to the stream perhaps for water channel there would normally be a drain out from underneath the half of the furnace because if you get steam underneath a furnace you do get a big explosion and they didn't want that um i mean i hesitate saying it's the corner of the furnace yet i mean it could just be the spread of the slag couldn't it it could be is that actually the edge of the lawn we're looking at there or have you gone oh it is so we've got this lovely lawn but actually the implication would be that we would take up the water i would go into the flower beds and right across the lawn i feel we've we've done the sort of one little keyhole investigation here we need to get something bigger that joins up if we come right across here we'll see what's going on outside this building if it is a building as well as what's going on inside it so trench one will investigate the area where the big dig test pit revealed a layer of blast furnace slag our first target is part of the elizabethan furnace complex possibly the corner of the furnace stack itself we'll be keeping our eyes open for evidence of a medieval furnace too although if there was one here it's likely to be buried much deeper the chances of uncovering any of it today are pretty slim while the diggers get busy i've tracked down the owner of furnace cottage rob chapman to find out why he invited us back in the best of all possible worlds what would you like us to find well i'd like us to find evidence of something like this having existed in the garden it's great having an illustrator in the garden isn't it it's amazing the furnace may possibly just have been at the other end of the lawn where the test pit was and we're sitting sort of about here and this little stream is still there at the bottom of the garden we've a pretty good idea of the sort of thing we're likely to find in rob's garden most elizabethan furnaces were built to the same design at the center of operations stood the furnace stack itself the raw materials charcoal and iron went in at the top a huge pair of bellows powered by a water wheel raised the temperature to the level necessary to smelt iron which was then run out into sand molds in the casting house but the furnace stack would have been the centerpiece of a much larger industrial complex stretching out into the woods and valleys around furnace cottage stewart wants to piece together this bigger picture and he's plotting his campaign with the help of county archaeologist bill klemperer and you can see as well that the area all along the chernic valley even nowadays is very heavily wooded with all this all these green patches on the 25 000 map because you need lots and lots of timber to support the charcoal smelting itself that's right so a whole industry in itself um creating the charcoal managing the woodland so it's not exhausted too quickly and that's all being brought to the furnace site in horses and carts in the field across the stream from rob's garden geophys are extending their survey it's possible that parts of the furnace complex and maybe even the furnace stack itself could have been sited here meanwhile in the incident room carrenza is finding out more about the origins of the furnace the brainchild of elizabethan entrepreneur francis willoughby and one of the most powerful women in elizabethan england local landowner bess of hardwick this sheet here is actually the um the business plan it's only on one page that this effectively spells out the plan that was produced in order to raise the capital for the ironworks at oklahoma that's amazing so you see he's listed the furnace and the forge and every single little sort of thing a ton of sows of iron stands in all manner of charges and then the figures for every single item isn't it amazing to have that sort of detail it's wonderful for this for this age to survive these account books so completely is absolutely wonderful we're still shifting the spoil from trench one there's no room for a mechanical digger so everything's being dug by hand it looks like it's gonna be a long day for phil there will be more but the trench hasn't taken out quite as much of the lawn as i'd expected hey this is only half as long as it's supposed to be actually it's um less than half as long it's only four meters long but we democratically agreed that we would dig a trench all the way right to the end of the grass democratically was it well i unanimously voted that it was going to be only four meters long that's the behavior of a tyrant phil why have you done that because i want to save myself a lot of work too if you look over there look how much topsoil we've generated from a little tiny hole think how much you were going to get from 10 meters and how much further we've got to go now well you can tell corenza all right send her over listen as well as that are you going to put in a test pit there and another little trench over there or have you decided that all you're gonna do is this would you prefer me to put in two extra test pitch yes but of course because that's what we agreed on then i should do it we know the elizabethan furnace would have used bellows driven by a water wheel it was water power which delivered the blast of air necessary to get the furnace hot enough to produce cast iron it's possible the medieval iron makers would also have harnessed the power of the stream here while stewart searches for evidence of water management gefiz have completed their survey of the field on the other side of the stream we asked geoff is to do a bit of work in this field because the topography is so interesting you've got what appears to be an ancient trackway coming down here sort of peters out around here and you've got this platform here and over there in front of our cottage you've got this other platform here john is the gif is as interesting as the landscape it's far better far better look at these absolutely fantastic responses again and they run right at the edge of the stream and well i'm wondering if they're more slag deposits i'm not so sure about slag i mean one of the things that's kicking around in the mole hills down there are little bits of roasted ore so one possibility is that it's perhaps where they're preparing the ore what about the the actual landscape it does look as though it's platformed off here yeah but come and look because the anomalies basically start here in this level area and they come right down to the edge of the stream where we've just discovered stuart hello mate hi what are you doing here well there are two ways to practice archaeology tony one is to sort of blindly rely on science or the other is to use your common sense and here there's this platform and the stream has cut through it so it's basically given us a ready-made excavation section through it john called it an earthwork do you think it's an earthquake oh it's definitely an earthwork and it's artificial it's got regular sides got a regular plan shape and then when you look through the section here where the rabbits have been scraping you can see it's made up of a slag and this clay possibly a bit of a furnace lining there and it's all down this section here ready-made section this platform could be the site of a storeroom for the furnace or maybe the furnace stack itself trench two will investigate further we've also opened a third trench in the garden here [Music] meanwhile phil's uncovered our first real archaeology now we're on to this much blacker stuff it's harder too can you hear it i mean it's really compacted and it's got these big lumps of of slag in it yep oh that's nice that's absolutely classic blast for this slag it's green it's glassy and it's light light in weight there's no iron in this i've got a good clean separation between the metal and the slag and the sand interests me too because that that sand could could be the sound of the actual casting bed but they ran the molten iron out into have a look at that oh yes feel the weight of that well it wasn't so much the the weight of it that attracted more it's rusty that's right it's rusty and it's heavy as hell for its size that is a piece of iron that's a piece of iron yeah so here we've got both parts of the process we got the slag waste and we've got the end product the iron it looks to be like we're smacking the casting house of the furnace well i think we'd better go down and see what this layer gives us this looks promising if phil can prove that his trench contains part of the casting area it means we're close to the heart of the elizabethan furnace complex but we also hope to find evidence of medieval iron working the test pit we put in during the big dig turned up a single tantalizing fragment of what's called bloomery slag it suggested people might have been making iron here for centuries before the blast furnace this is 13th 14th century round about the time of the black death we have no idea there was a bloomery here at that date our medieval iron workers would have used one of these a bloomery furnace a clay chimney about two metres high the raw materials charcoal and iron ore went in at the top bellows were used to raise the temperature inside and after a few hours a lump of iron and slag called a bloom would form this was removed and refined to produce workable iron bloomery bellows were usually hand operated but occasionally they were driven by water power which made it possible to keep the furnace hotter for longer and produce better iron the stream near furnace cottage raises the possibility that a bloomery in rob's garden could have been water powered only a handful of these have ever been discovered in this country so to find one here would be a fantastic result but although we've dug much deeper and wider than the big dig test pit we've found no further evidence of medieval iron working that solitary piece of bloomery slag is starting to look a bit lonely it's the only piece that's turned up so in my view i think it's a red herring i think that it's probably just a piece of slag bought in for some other reason remember it was in that top 60 centimeters that phil said was really garden it could have been bought in just to decorate a piece of rockery or perhaps just as hardcore or something absolutely yeah yeah oh right okay so i think really that's the end of that story this is a bit of a blow we hoped the garden at furnace cottage would contain evidence of centuries of iron making in the valley but so far we found nothing which predates the elizabethan furnace if we want to take the story back to the medieval period we'll have to cast our net a bit wider [Music] there's no doubt the people were making iron in this part of staffordshire during the middle ages the countryside's rich in the two main ingredients of the process these woodlands provided the timber necessary to make charcoal and they were also a rich source of iron ore this may look like a muddy pond in fact it's the remains of an open cast mine supplying material for the furnaces in the valley i think the whole area would have been buzzing with activity you know all these valleys they were being full of woodland but they've been people working in them either producing the charcoal or mining the the materials they needed or transporting stuff patterns and fords in by pack animal and various forges and mills and stuff in the bottom so totally different picture very industrialized probably very noisy and very smoky not the view you've got today at all so this wasn't the only furnace around here oh no there'd be lots of other sites the critical ingredients for the island industry the the the woodland the the the iron stone itself and the water power exist along the chernic valley and its tributaries over quite a large area so there's a number of documented sites which we know about there's other documented sites which we don't know about and there's other other sites in the woods here waiting to be discovered mick's taken a look at some of the other medieval sites recorded in the valley he likes the sound of this one at east wall because it's mentioned in some 12th century manuscripts from the nearby abbey at croxton stuart's gone to investigate the earthworks although i have to say he doesn't exactly look overwhelmed but at least we've still got plenty to keep us busy at furnace cottage in the field across the stream we're still investigating stewart's platform trench and just as we've given up hope of finding anything medieval in the garden bridget's come up trunks you're my last hope you got anything earlier than the 19th century here actually it looks as though i do two pieces of pot here look very medieval great let's have a look what do you think they are yes that's um a storage jar or cooking pot okay and it's 12th to 14th century and it's it's good because on the big dig yeah at this site a few shirts were found in the test pit this is the biggest piece it's from the same sort of thing a cooking okay yeah you can see the turning marks can't you yeah and it's again 12th to 14th century the plot thickens it would be nice to believe this 12th century cooking vessel was used by workers at a bloomery furnace in rob's garden the only problem is we still haven't found any more medieval slag or other iron making remains to back up the theory and some members of the team are starting to think our best chance of finding a medieval furnace may not be at furnace cottage at all but a mile down the road at east wall this is east wall where we've been told there should be evidence of more iron working and ever since we've been here you've been skipping around a little lamb haven't you yeah i think this is an ideal settlement site if we're looking for places where there might have been furnishes and so on and workers to work them this is the sort of place i would come it's a nice flat platform above the river with good steep slopes on each side and woods and so on so where do we put the trenches well it's not as simple as that stewart's looked at the earthworks which i you know i was prepared to put money on there were cottages and so on he doesn't like them he thinks there might be a few gardens here and he thinks a lot of the rest of it's natural and the document that led us to the place in the first place i think needs re-examining we're not quite sure we're on the right place for it here but you've done the gfiz here haven't you and you think it's great well i think it's a fantastic site i mean the farmers told us about all the slag is found in this field and i mean we've got some superb results i mean look at this there's anomalies all over like could all be to do with metal working and i certainly want to dig but you want trenches yeah definitely i just don't really feel we should be doing here at all i don't understand why we suddenly want to dilute our effort we've got more than enough to keep us occupied at old furnace i think we should do one job properly my worry is the amount of space at old furnace you know how much of that chaps garden are we actually going to be able to trash to well again i think rob is very interested to see the buildings there we can extend the trench that fills in well in two directions and go into the bottom of the garden and there's the whole area the other side and the water wheel we're not gonna reach a consensus that's the reality isn't it i suspect this one's gonna run and run and it won't be resolved until people have had some alcohol and a long night's sleep either we pour all our resources into rob's house or else we start digging trenches here or else maybe we just survey here one thing though that everyone seems convinced of is that we're tantalizingly close to finding the furnace at rob's house will we hit it tomorrow join us after the break beginning of day two and last night no one could make up their minds what we should do on this site where an ancient document said there was once a medieval furnace should we put some trenches in should we just survey it or should we leave it alone because there's such interesting archaeology on the other side well we agreed that we would decide this morning and in true time team fashion no one's taken a blind bit of notice of that and they've started digging already what happened to this meeting to decide what we were going to do here we've had it you've had it we've had each year is carenza here she's on the other trains no we've decided why haven't you decided well look one of the things we were waiting for is for a chance to reprocess the results we've got some fantastic responses if we look at the plan looks like a ditched enclosure coming round uh and these strong anomalies here and what we decided to do is put a small test pit in just to have a look and kerry started digging that what's it like kerry it's rock hard all over why it's solid slag it is slight it is yeah so what we want to do is extend the trench to see if we've actually got some sort of structure in there this is too good to ignore okay i'm sure there won't be any rails about this so more slag for our diggers to hack through but underneath it may lie our best chance of finding an early bloomery furnace in fact it might be our only chance at furnace cottage we've uncovered some medieval pottery but still no sign of iron working before the elizabethan period and all that seems to be coming out of phil's trench is yet more blast furnace slag this is the sort of stuff we've been finding that's in there there was just a big layer so this is material that's actually come out of the bottom of the furnace it's just the debris that was thrown away but nothing medieval no no no you want medieval well it wasn't weird or at least i think i can look at that i'm no expert but that's looking as all that could well be medieval to me the beauty of it is it's stratified that is as good an evidence for the dating and that slaggy because you're likely to get but the slag keeps definitely blasphemous the technology is blessed well may you look look at it jerry you've got any bits no no no that's medieval that's what we classify as medieval taps so we have got it here hang on you were saying you were pretty certain we didn't have any evidence from medieval bloomery and that this had come in as a bit of garden yeah you can't build a medieval bloomery argument on one piece of slack but can you build a blooming evidence yes if the if that is consistent with the other material that's coming out of there then that looks to me i haven't been examining every piece i've just been shuffling so so the story has changed again yes we have got evidence from medieval blooming this is what we came back here hoping to investigate and it looks like there really is something to investigate possibly our medieval bloomy perhaps water powered yes and what we need to do really is i need to take some of this back to the lab and get it sectioned and cut up and have a look at it as fast as you can this is just the breakthrough we've been hoping for it means the hunt's back on for a medieval furnace in rob's garden and if that wasn't enough a mile down the road at east wall farm we're hoping to find another one but even if there was a bloomery furnace here in the middle ages there's no guarantee we'll find any surviving structures so we're going to build our own reconstruction of a medieval style bloomery phil's taking a break from slag shifting to check up on progress and now tim i thought you were building a furnace all you got is a hole in the ground no we mustn't confuse these with with later blast furnaces that are really big is a really quite small scale we can still make quite a substantial piece of iron in it but it's pretty small and they're going to be made out of bricks the superstructure would originally just have been solid clay so we've got perhaps a month of drying of clay before this would take its own weight so what we're doing is to fit in with the time scale we're putting a brick framework inside the wall of the furnace to support the clay so the thing hopefully can stand up uh in time to be used let's go and build it okay we want to smelt some iron here tomorrow so our bloomery builders have their work cut out by using bricks as well as clay we're speeding up the construction process but we're departing from the tried and tested medieval formula we won't know until tomorrow whether it's been a good decision the valley at furnace cottage we've called a halt to work in trench four which was investigating an earth work platform across the stream from rob's garden we think this would have supported a bridge leading into the furnace complex another piece of our elizabethan jigsaw slots into place as we dig deeper into rob's lawn bridget's finding more evidence of medieval iron making guess what more slag good good good look at this in this pile we've got the blast slag right but we do have little bits of um the blue marie slag look at this lovely piece that's a superb piece of medieval bloomery slag where it's flowed out and the surface is cooled really like sort of jam and then the crust cools and then the rest freezes underneath it's just so it's really quite sensual looking isn't it yeah you're using this ties it with with phil's lair that we're down into the medieval there yeah but what's interesting really compared to phil's trench there's very little blast furnace slag right okay so have you got anything else yeah well actually i'd like to have a look at the section here because we've got these layers of sand this brown underneath and then this lighter sand again have you got any idea what's going on right well the sand is is critical in in the blast furnace process for casting the metal into as it flows out so what we're really seeing here probably is the debris from the casting house and so this is just being thrown away once it's been used several times it just has to be discarded but we are going down into the medieval now yeah we want to see if we can find the medieval land surface okay keep digging find more we're still trying to piece together the layout of the elizabethan furnace complex carrenza's opened a new trench to target a channel which might have carried water away from the water wheel and back to the stream so now we have three trenches open in the garden we think the sand and slag in phil's trench are the remnants of the casting area where the molten iron was tapped from the furnace based on what we know from other excavated sites it fills trenches on the edge of the casting area then the heart of the complex the furnace stack itself must lie further up the slope here we'd love to put in a trench to find it but there's just one small problem furnace cottage itself we can't ask rob to demolish his family home so our experts have come up with a plan b instead so if we didn't go all the way to the house you're saying that we should start here somewhere and yeah and both yeah come down to sort of here yeah i think you need to talk to rob about it it's his garden i reckon he'll be relaxed about the path but a bit worried about anything else have a word with him sounds like he's down to you tone that well thank you very much why do i always get this job [Music] after breaking the good news to rob i make my getaway with stuart we've taken to the air to investigate what makes this such a suitable location for a blast furnace there are three valleys all come together you've got the main valley here you've got this valley up this side coming where the road comes down and you've got this one where this pack horse trail comes down and valleys are are vital to to the process of of smelting and blast furnaces for the simple reason you've you've got water down there and it's the the proximity of water that's needed to drive the bellows to fire the furnace so you need a sighting where you can harness the natural resources of water you need to be able to create dams to store water you need to be able to manage it through a network of leaks and channels so that it arrives at the water wheel at the right speed and constantly yeah from the air you can see much more clearly how strategically placed our furnace is yes at furnace cottage we're still piecing together the layout of the elizabethan furnace we know from the account books that it was turning out huge quantities of iron each year so it must have been a pretty impressive structure we think the central furnace stack must have stood close to the cottage itself rob's given the thumbs up to our trench extension which is our best chance of finding it and it all hands to the pump at our experimental archaeology site where we're building a medieval style bloomery the furnace is really beginning to take shape now which is just as well the building needs to be finished today if the clay is to have any chance of drying out so we can smelt some iron here tomorrow [Music] it's the sort of structure we're hoping to find at east wall farm where it's time for someone to eat some humble pie yesterday stewart said he couldn't see any evidence in the landscape for a furnace here but john's dear fizz told a different story all i can tell you is that john called me on the intercoms and asked me to bring you over and there was the sound of triumph in his voice he's looking smug isn't he what you got for us john i think i'd just like to say there's two ways of doing archaeological survey one is to use your common sense and what you can see with your eyes the other is to do it scientifically well if we'd had done this with common sense i think somebody said there was nothing here but actually if we look at the scientific results we've got something fantastic an institute furnace john that was the longest bloat i've ever heard jerry is it really a furnace yes it is definitely what can you what can you see that makes you so certain right what we've got over there is very heavily slag attacked clay lining we then got burnt red lining which slowly changes to unburnt clay so what i predict we've got is the furnace just under here which will be about 40 centimeters in diameter internal and then what we'll have coming down here is a tapping channel where they ran the slag out into the pit down here is it possible to date it at all at this stage it's difficult because essentially this technology is in britain from the late iron age onwards but one of the things is that this slag is quite distinctive it's very like a sort of a crunchy bar texture and i've seen that in in other research areas very much related to the medieval period yeah i think i can help you out with the data we've got uh two pieces of uh 13th 14th century whitewater and they've actually got a little bit of slag on them well that seems pretty confusing it's got the slag on it fantastic so how are you feeling about this impressive very impressive mister no there's no furnace here no no i never said that when i looked at this landscape here were there any earth works here which are indicative of bloomery signs and the answer to that is no not on the surface that's one of the great problems of looking for these sites because archaeologically normal field walking they're invisible you have to use common sense and looking for slag and finding slag and then applying geophysics because that's the only way you can understand these signs so finally after nearly two days of backbreaking work we get our first glimpse of a furnace structure it's possible the iron makers here would have harnessed the power of a nearby stream to drive the bellows of their bloomery if they did we might reveal something really special here tomorrow and we'll also find out if our replica furnace is up to the job of smelting some iron oh that looks so good you're really proud of this aren't you yeah you bet so you should be yeah this is actually the clay from the farm it's just dug out the back of the barn on the farm and it's uh it's marvellous stuff can i feel it yeah it's very damp isn't it yes so that's our next job we've got to fire the kiln now just to give it a bit of a drying out and hopefully i'll be ready for the morning [Music] it's the end of a hectic day too we still have our work cut out to unravel the story of furnace cottage but it's already becoming clear how much the garden and the surrounding countryside was shaped by the industrial activity that took place here over the centuries you see how deep that pit is down there we are still at the bottom that going through the medieval slag heap the whole of this ground surface we're standing on is completely artificial the surface says cottages are built on that the trees are all growing on the whole of this bit of the valley wasn't here in the middle ages it was all right down there there's a completely different landscape then and that is all because of the iron working here what about the extension to this trench well of course this is our great white hope at the moment everything is telling us that both the medieval bloomery and the elizabethan blast furnace are up the slope here because all the slag the waste product has been thrown away down the slope so hopefully this trench should have within it either of those furnaces or even possibly both of them so it's the end of day two yesterday we were hoping for a glimpse of a furnace and we got one except that it wasn't here it was about a mile away at the other site tomorrow we think there are two furnaces here but in order to find them we've got to get down not just to here not just to here but right down to here can we do it join us beginning of day three in our quest to piece together the story of centuries of iron making in this square mile of the staffordshire countryside and with two sites up and running there's plenty to keep our archaeologists busy at furnace cottage we're piecing together the layout of an elizabethan furnace complex in the garden we're getting closer to the heart of the operation the furnace stack itself we're also discovering how the 16th century iron makers left their mark on the surrounding countryside the streams in the valley here would have been channeled into the site to drive a water wheel which powered the furnace bellows stewarts investigating how it was done the discoveries we've been making have inspired the owner of furnace cottage artist rob chapman to take up his brushes they're based on the names taken from the the accounts for the furnace it's uh it's really good that we've got um names for all the people who worked here i wanted to put faces to those names so these are real people part of our story humphrey beddle william beardmore i mean humphrey beddle was like a hired gun who was brought in to set up the foundry he was the expert who could make it work he was the first founder here but this guy's really nice as well because this is william beardmore he's he's not a hired gun he's a local lad he's working here as a labourer rob's next-door neighbor dorothy has a special reason for taking an interest in this chap he's one of her ancestors how are you related to him well this is my family tree and is here so you're the great great great great great great great great great great granddaughter of this bloke that's right do we have much evidence of many other people we have masses of names every week there are detailed accounts kept of exactly every single person was paid here you see william beardmore here is being paid for stoneworking for labouring so how much did he get not a lot i bet about nine points a day but he looks happy enough on it [Music] i'm heading for our second site at east wall where yesterday we began to uncover the remains of a medieval bloomery furnace we thought it might have been damaged by plowing but we needn't have worried it's beginning to look like something very special indeed matt that is a lovely piece of archaeology isn't it it's great isn't it can i have a closer look yeah yeah take it get down there thanks so what have you done since we were here yesterday afternoon well we extended the trench out this way to get the rest of the rest of the furnace and as you can see you've got it absolutely solid base of the furnace here and it's packed around with these stones here so the wall of the furnace originally would have come out to about here out that side we've got the slag tapping channel so all this slag byproduct have been scraped out filling this enormous hole over here jerry this looks to me like the crater of an enormous pimple what can you tell us about what was going on here right what we're looking at tony you've got to remember is we're only really looking at the really the bottom portion of the furnace originally it would have stood perhaps two meters higher than us so we're really looking at a truncated bottom bit but it's really the heart of the furnace where the really high temperatures we're operating at we've got this thick lining which insulates the furnace and the type of slag that's coming out is this very which i call crunchy bar or arrow-like slag and what it tells us is that the slag coming out is very very hot because the the bubbles in it are actually trapped air that get trapped while the slag is very hot and as it cools the air is released and forms these bubbles so one thing that i'm thinking that comes out of this is in order to get those temperatures we've got to have water power if we found that this furnace was water powered would that be particularly significant it would be very very significant really important there are very few examples of known water powered sites and as my opinion none have been satisfactorily excavated so it'd be the first this site's getting better and better water powered bloomers are the crucial missing link between the standard bloomers and blast furnaces they were developed to meet the growing appetite for iron used in farming implements household tools and weaponry to find one here would be a major discovery but we'll only know for sure once jerry's taken a closer look at the material coming out of the trenches the smelt's beginning at our own reconstruction of a bloomery the recipe for iron is pretty simple iron ore and charcoal are introduced at the top of the furnace as the temperature inside rises they should react with the clay lining of the furnace itself to produce the bloom at least that's the theory the only problem is the clay hasn't dried out as quickly as we'd hoped only time will tell if these running repairs will be enough to salvage our experiment in the garden at furnace cottage phil's finally reached the natural geology in trench one [Music] we've been working on the assumption that the steep bank of sand in here was the remains of the casting area for the elizabethan furnace we've got all this sandy material with lots and lots of charcoal and then over the top of that we've got a series of of slag deposits so this is lying on this sandy stuff is that right yeah this is this is this is right somewhere near the bottom now it's sort of dawning on me that sand cannot possibly stand up on its own an angle like that it could not possibly stand up on its own so i think that that sand has been there and then they've chopped through it and then all this slag has been dumped over the top before it's had time for that sand to fall away so this sandy material could be a lot earlier than this slag okay like what i was just wondering is whether this actually this burnt material is actually the remains of the medieval bloomery that's then subsequently been cut away and fashioned away and then the the elizabethan blast fern is debris and casting debris coming right on top of it phil's trench captures the moment 400 years ago when the elizabethan iron makers ripped through the remains of the medieval bloomery digging a pit to dump the slag waste from the blast furnace it means we can now pinpoint the location of the medieval bloomery here and the elizabethan blast furnace further up the hill here just as we hoped rob's compact garden does contain two furnaces after all we're approaching the moment of truth at our medieval style bloomery if the smelt's progressing according to plan it should be possible to see some liquid slag running out at the base of the furnace the early signs are encouraging you've got some deck you see it dripping at the back ah yes you can see it dripping in front yeah i can we need to stop we need to yeah we need to free that a bit more needs a little bit more but it will come you ready now i think yep but then the alarm bells start to ring start to flow nothing happening should it have gone by now i would have hoped it would have done but it's one of the unknowns we've got a different clay that we're using here so we really don't know what its properties will be there ought to be more slag than this perhaps we're rushing things too much so the furnace is sealed again to allow a little more time for the iron bloom to form it's time to put together the final pieces of the furnace cottage jigsaw based on a geophys survey of this field we put in a small test bit in this area in it we found locally sourced iron ore and this elizabethan pottery the first anywhere on the site that's just what i hope we'd find up here it looks like we've got the storeroom from elizabeth glass furnace it's another site to add to stewart's map of industrial activity in this valley clearly in the medieval period the bloomer is just sitting alongside a stream in this river valley yeah nothing particularly unusual about that i don't think but by the elizabethan period it all changes into a into a managed valley yeah to to service the the industry here they'd put a dam across the valley and create a pond behind another one up there all harnessing these streams around here so the whole thing fits together there's a whole piece of managed landscape a lot like the other other furnace sites we see elsewhere yeah yeah now the so debate here is where is the wheel is it on this upper channel or on the other one or on that one there i think that question is is unresolved at the moment i suspect i actually don't think it matters as long as you've got two channels because one of them is is running the power and the other is the bypassing case that's right yeah the other interesting thing i've found here is that there has to be charcoal storage here that's often the biggest building on the site in many cases and i think under here under furnace farm is the charcoal barn area and it's evolved into a into a farm the 16th century blast furnace at oklahoma was the centerpiece of a major industrial complex which left its mark on the woodlands and waterways for miles around night and day for nearly 15 years it drew on the rich natural resources in the valley to meet the huge elizabethan demand for iron used in everything from cannons to cutlery and at the heart of the operation was the furnace stack itself which once stood precisely where furnace cottage is today it looks as though the furnace rob wanted us to find was even closer to home than he realized [Music] things aren't looking good at our experimental bloomery the slag which should have gathered at the bottom of the furnace has attached itself to the lining instead and it's a major job to prise it off so what is that then a slag that is slag that's what should have poured off then yeah so now we've dealt with the slag it's time to play hunt the bloom oh is it so this should be our bloom well [Laughter] it doesn't look much different from the slag but after a little closer examination it gets the thumbs up from our expert this spiky texture around here that looks like iron right so i think we've got we've got bloom on this side this bit is bloom i think right now it's probably not the world's greatest one or the world's largest one but it's a bit of iron any self-respecting medieval iron worker would have thrown this disappointing specimen back into the furnace and started again we don't have time for a second smelt but we're determined to produce some pure iron so the bloom's reheated in the furnace then hammered to remove the excess slag and this is what we're left with not much to show for two days hard work but pure iron nonetheless in the incident room jerry our metals expert has been taking a closer look at the slag samples from the medieval furnaces at our two sites they could help us answer one of the major questions of this dig were either of the furnaces using water power this is the sample from old furnace this is the bloomery slag and what we see on the screen is the microstructure the crystalline structure of the slags now what's important is this white christmas tree material because this shows that this process that was used at old furnace is not particularly efficient because that is iron oxide that could have been reduced to metal right so the more white sort of tree-like patterns you got the the less efficient the process okay and that's pretty typical of a number of bloomery furnace slags that you'd see virtually across the country so as we suspected no evidence of water power at furnace cottage but how about east wall oh no it doesn't have the little christmas tree structure that's right no it is there but it's incredibly incredibly fine right what this means is that the process at east wall was tremendously efficient it's got really strong reducing conditions which means that they are being most efficient they're reducing every available piece of iron oxide to metal now put that in with the high temperature frothy slags it means that we are seeing a step changing technology between old furnace bloomers site and east wall bloomers site and because of the nature of that technology it is moving towards as it were blast furnace technology and in my opinion the step change is water power it's exactly the news we've been hoping for the furnace we've uncovered at east wall farm was a high-tech piece of middle ages technology it's incredibly rare and remarkably well preserved how have you got on then matt since this morning well we've emptied out the kiln now can we come in your trench yeah yeah get down there um and it's a little deeper than we first thought oh we don't have that huge layers of charcoal which we may get inside furnaces like this what we did have at the bottom there was a layer of this slag we've got slag left over in there oh crack it's very light very light isn't it they must have got rid of most of the metal out of that yeah yeah right there was no natural bloom or blue remains presumably in the last use they they took out the bloom and and used it yeah ayan can you see where the bellows might have come into this yeah i think we've got just the bottom of it here and that curving aperture there that's where the bellows came in and that lumper slag there that's where where it went out underneath through there down to the tube that's coming out towards you kerry then well we've got a very nice section across the chamber where the slag would have flowed out and there's still some slag here on the natural in the 12th century there would probably have been several furnaces at east wall but these were no ordinary bloomers by harnessing the nearby water source to produce iron of the highest quality the iron workers here were making a crucial step towards the later blast furnace method of iron production [Music] the bloomery at furnace cottage was a much humbler affair the burnt sand in phil's trench is all that remains of it the rest is long gone obliterated by the elizabethan ironworks built here in the last years of the 16th century it's just gone seven o'clock nearly everyone's gone home but just over ten minutes ago one of the diggers found this and debbie says it's definitely anglo-saxon nice find excellent we've got to think that if this was a good enough place to smelt in the elizabethan period the medieval period then it was probably a good enough place to smelt in the saxon period you said three weeks ago on the big dig that you thought this place could be of major archaeological importance are you pleased i am yes i mean was it luck or judgment but i can't resist saying i told you so fair enough but there is a downside isn't there you've spent the last three days drawing all those beautiful medieval figures and now rob you're gonna have to start drawing saxon ones thanks a lot over the last three days we've shifted more slag than i ever thought possible but all this work's given us an insight into the hive of activity that once took place here generations of people worked in the mines and forests feeding furnaces like the ones here in rob's garden and i feel that we've got closer to those people and the amazing technological advances that their skills and energy made possible not only that but we've proved that that activity took place for nearly a thousand years not bad for a story that started with just one small test bit [Music] you

Channel: Timeline - World History Documentaries

Views: 76,557

Keywords: History, Full Documentary, Documentaries, Full length Documentaries, Documentary, TV Shows - Topic, Documentary Movies - Topic, 2017 documentary, BBC documentary, Channel 4 documentary, history documentary, documentary history, time team, elizabethan history, british history, tony robinson, british archaeology

Id: 86TNztiFltA

Length: 49min 11sec (2951 seconds)

Published: Tue Mar 02 2021