TechStuff Classic: How the Industrial Revolution Worked, Part Two

on November two thousand and fifteen. Fortunately, unlike a lot of my topics I cover on tech Stuff, the Industrial Revolution has not changed significantly in the last seven years.

So let's sit back and listen. Now. In that last episode, I focused mainly on the textile industry because it's a great illustration of how quickly things changed just within a few decades and went from something that used to be a specialized skill among we vers that would do you know, maybe a couple would work together, but that would be it, and it would be something that would be produced on a very small scale, to a full blown industry which

would end up employing thousands of people. Now, in this week's episode, we're gonna look more closely at how iron shaped the Industrial Revolution and how innovations and inventions in the iron industry really changed things, and it's it's fascinating and also kind of complicated. Now, first of all, iron is the second most common metal in the Earth's crust. The most common would be aluminum. But we would never really use chemically pure iron, you know, the fe stuff

to build anything of any significance. And that's because of a couple of things. See, pure iron is really malleable, so that it means it's really easy to shape, so that's good. And you can even cut pure iron using something like a knife. If you've got a hunk of chemically pure iron, you can cut through it. It does take some effort, it's not like it's gonna slice through like butta, but you can do it. You can use a hammer to beat pure iron into sheets, or you

can even draw it into wires. And it's great stuff. I mean, it conducts heat, it conducts electricity. It's also really easy to magnetize, so it's got a lot of uses. But it isn't strong or hard enough in order to use for building structures like bridges or buildings or canals or or even common tools. It's not strong enough to to do that. It will end up bending too too much. So all of that is kind of a moot point because there's something else about iron that gives it a

huge drawback. We don't see much pure iron because it's got a habit of getting really familiar with oxygen. Oxygen corrodes iron, particularly in moist conditions, so that causes a chemical reaction in which pure iron forms an iron oxide that we call rust. So that's essentially what's happening, is this chemical reaction with iron and oxygen creates this iron

oxide of rust that we don't really want. You know, there's always about you know, you have to scrub down the rust and get rid of it, or else it just continues to corrode. Well, because iron reacts so readily to oxygen, we don't mind iron in its pure form. In fact, we just we don't find it because it

oxidizes so quickly. Instead, we mine iron oxides that are locked inside various types of ore, including hematite, which is the most plentiful ore that contains iron, limonite or limonite, depending on how you want to pronounce it, sometimes called bog iron, and magnetite, which is also known as loadstone, among others. There are a few other versions of iron ore as well. Not all ores contain the same percentage of iron by volume, and we mine iron both in

underground mines and in surface mining. It all depends upon where you are and where the iron deposits happened to be. Now, the iron ore in Britain, because that again is where the Industrial Revolution began, had really high concentrations of sulfur and phosphorus, and both of those things will make iron brittle if you don't get rid of them. So until the Industrial Revolution, iron masters hadn't really quite worked out how to do that on an efficient basis. For that reason,

British iron was often used in very cheap items like nails. Now, this was also a little tricky because iron making iron required a lot of labor, a lot of backbreaking hard work, and that drove up the price of the final product. So Britain was starting to supplement its own iron supplies by importing about half of all the iron it was

using from Sweden. The iron from Sweden did not have the high concentrateations of sulfur or phosphorus, so it wasn't as problematic, and Britain just couldn't produce enough of its own despite ample supplies of iron ore. Now, once we get hold of iron ore, we have to smelt it. That's in order for us to get to the iron that's inside of it. Now, this involves heating the ore up to the melting point of iron. We also use fuels that will produce chemicals that can bond with the

iron during this process, which changes iron's physical characteristics. We're talking chemical reactions here, and what we're really doing is creating iron alloys. And an alloy is a mixture that has a metal with something else. Sometimes it's another metal, sometimes it's a different substance. But these are chemical mixtures that have their own features that are different from the features of the individual elements or or ingredients in that mixture,

so you're getting something new. The main ingredient we mix with iron to produce useful material is carbon, and if you get the mix of carbon to iron just right, you produce steel. Steel is an iron alloy that has around two or less carbon in it. Other types of iron hab between two to four of carbon in the alloy, and mixing other metals or substances will create different types of steel or iron. So how do you mix carbon into the iron? What exactly are you doing here is

there's some sort of powder that you're pouring in. Well, one way is by using a carbon rich fuel as the means of heating up your iron to melt it in the first place. So if you're using something a fuel that has a lot of carbon in it, then some of that carbon gets transferred into the iron as it melts. Charcoal is a great example, and iron masters in Britain and really all over Europe relied very heavily

on charcoal for centuries when smelting iron ore. But if you remember from our last episode, I talked about a man named Abraham Darby who came up with an alternative to charcoal, and it was coke. Now, coke is a fuel product you make by baking coal in an airless oven or furnace at a really high temperature, and at that high temperature, some of the coal begins to ash.

That ash will end up melding with the the coal itself and it converts into this other fuel called coke, which is once it cools down, grayish in color and has a very porous structure. When you burn coke, it creates carbon monoxide, among other things, which is important in this process of creating iron useful iron. But why would anyone worry about switching from charcoal to coke in the first place. I mean, charcoal is pretty simple. You just have to burn wood to make charcoal. Uh. And in fact,

this is where the problem would come in. In order to fuel a single iron works for one year, it would take two acres of forest to supply enough charcoal for operations. So for one iron works, you would need two hundred acres of woods. And keep in mind that once you've gone through that that two acres of forests in a year, you're not gonna be able to use those same two hundred acres the next year because it's going to take time for that forest to grow back.

So we saw a steady decrease in the forests of

Britain during this time period. At this time, iron works were mostly located in forests because it was cheaper to ship the iron ore and iron from the iron works or to the iron works, and from the iron works then it was to ship charcoal around, so they located the iron works near the fuel, not the iron ore, which seems counterintuitive at first, but eventually the growth of the iron industry and the fact that more and more people were building ships during this time period for England

meant that England was using up more wood than it could replenish, So charcoal became more expensive because forests were being chopped down, wood was becoming a scarce commodity comparatively speaking compared to how it had been in previous centuries, so it became really expensive to use forests just to generate charcoal. So an alternative fuel was definitely needed to

make British iron and actual commodity. Now, some iron masters tried using coal as fuel, but burning coal produces sulfur, and that sulfur would react to the melted iron ore and produce an iron that was too brittle to be of much use. Coke, however, didn't produce nearly as much sulfur when burned, and the carbon monoxide coke produces wind burn would mix with the melted iron ore to create

useful iron. And if you listen to that last episode, you heard that Abraham Darby had developed a process for making pig iron by using coke as the fuel while smelting iron ore, but his approach wasn't adopted by the iron industry during his lifetime. There are a couple of reasons for that that, you know, the iron industry didn't

immediately swap to using coke instead of charcoal. One of those reasons is that Darby pretty much kept his process a secret and only told his son, Abraham Darby the second, how to do it. At the time, anyone wanted to, you know, get an advantage over their competitors, what they did was they kept their methods secret. Some people would

choose to patent ideas to protect them. Others decided that patents were bad because if you if you file a patent, the information on how you do something becomes public knowledge and eventually passes into the public domain. So other than patent of process, some people would try and keep it a secret. That's what Derby did. But the other reason is that Darby didn't live to a very ripe old age. He actually had a really long illness and died at

age thirty eight in seventeen seventeen. Now, his grandson, Abraham Derby the third would build the first iron bridge in the late seventeen seventies. But the Derby's method was really only good for creating a particular type of iron called cast iron. And I'll talk more about what cast iron is in just a minute. But first, let's talk about the smelting process. All right. So let's say you've got yourself an iron furnace. Typically we would talk about a

blast furnace. Blast furnaces are really giant cylinders. We're talking some of them being around thirty to forty ft tall and twenty to thirty ft square at the base, often built into the side of a hill. So that way, uh, in order to bring materials to the blast furnace, which you would deposit in the top of the furnace, you would climb the hill as opposed to putting scaffolding up or a long ramp or however you would you know, be able to have an access point to get to

the top of the furnace. Now, if you want to imagine what these things look like, they did like a look like a tapering cylinder. So the top is a bit narrower than the bottom. Uh. The topmost portion of the cylinder is called the shaft, and that's where you would feed the fuel, the iron ore and some other materials called flux, which is typically limestone. The purpose of the flux is to absorb some of the other elements inside the iron ore that you don't want corrupting your iron.

You don't want it to mix with the iron so that it makes it have properties that you weren't intending. So you've got your your flux, your fuel in this case coke or charcoal, and then the iron ore itself. You would put all that down the shaft. If you look down the cylinder, then the next section is called the bosch. This is a roughly circular chamber where uh

it gets incredibly hot. And below the bosch, at the base of the blast furnace was the hearth or crucible, and that's where the molten iron would accumulate before being drawn off by the iron master. Drawn off just means essentially drained from the furnace chamber. So this was actually a pretty complicated process. Uh. In fact, they were called blast furnaces because you would blow large drafts of air

into the furnace and what we're called blasts. The earliest blast furnaces were cold air furnaces, meaning that the the air being blown into the furnace had not been preheated in any way. The air would typically be forced through an entry point that's down the cylinder. It's not at the top, so you're not blowing air down into a chimney. Rather, you would have an entry point inside the furnace and

air would come in there towards the bottom. You want it near the bottom to fan the flames, and that would allow you to keep the fire burning at the right temperature. And you would do this with an enormous set of bellows. So you've probably seen bellows. These are the devices made to actually blow air into a an area, usually some form of furnace or fire that would provide the blasts of air. And in the early Industrial Revolution

they were powered by a water wheel. And when I say an enormous pair of bellows, I mean we're talking a big, big piece of machinery. They would be more than twenty ft long and four or five ft wide, So these were huge and would create very powerful blasts of air. Now, later iron masters would actually rely upon steam engines to power a blower for the furnace. But we'll talk more about steam engines towards the end of

this episode. So if you wanted to start up in ironworks, you've just you've just decided to get into the business, and you're an eighteenth century England then what you would need to do is build your blast furnace in a in a good location, get all the stuff ready, like the bellows and everything all prepared, and then you would need to get your furnace up to the right temperature before you actually started to add iron ore. Uh. You would do this in a process that was called blowing in.

Now that involved bringing a large amount of fuel into the furnace, whether it's charcoal or coke or whatever. You would have to ignite the fuel and allow it to gradually heat the furnace over about a week's worth of time, and once it was up to the proper temperature, you could finally get started with iron working. And when you're ready to smell iron, you feed the fuel, flux and iron ore into the top of the furnace. You're essentially

dumping things down this this cylinder, this chimney. Now, as those materials fall through the length of the furnace, they begin to heat up. There's a lot of very hot gases that are rising up through this cylinder, and the material passes through those hot gases, getting hot before they even get toward the hearts the crucible. The fuel begins to burn and the iron starts to heat up to melting temperature. The iron ore reacts with the charcoal or the coke, and that absorbs the oxygen in the iron

oxide that was locked away inside the iron ore. Now this is a process called reduction, and what you're left with is liquid iron and slag. Slag is actually not that hard to get rid of. You would think that this is a big, messy, slushy liquid that's molten hot, but in fact, liquid iron is very heavy and slag would float to the top, so you'd have the liquid

iron underneath and the slag on top. When you are ready to draw off the molten iron, you would open up a tap hole located in the heart level of the blast furnace, so towards the base of this cylinder. And typically these taps also had a little gate on them, and the gate would go up and down, and by setting the gate at the right height, you can allow the molten iron to pass through and it would hold

back the slag. So that way you just get the molten iron and the slag is left behind, because again the slag is floating at the top of this molten material. We'll be back with more about the Industrial Revolution after this quick break, so that molten iron would then run through a channel a trench essentially, and branch off into smaller channels on either side that acted as molds. So imagine that you've dug into some sand, uh some some some shapes for ingots, and you draw off this molten iron.

It flows down a large channel and then splits off into these smaller channels that are inget molds. Essentially, that cooling iron would solidify into the ingots, and those ingots were called pigs and the iron is referred to as pig iron. And you might wonder, well, where did this name come from? Why is it pig iron? Is it dirty iron? What? What's the deal? Well, the reason for the name is that iron workers thought that the the little channels leading away from the central channel were similar

to suckling piglets that were feeding from a sow. That the idea that these little splits, these channels were like piglets. And that's why it's called pig iron. I am not making that up. Pig iron is sort of a transitional point for usable iron. By the way, it's stronger than pure iron by about a hundred times, but it's still too weak to be of practical use for certain certain purposes like that, you can use it for tools and stuff, but you typically would use pig iron again by reheating

it and doing something else with it. Now, the next basic type of iron after pig iron is cast iron, which is really not that different from pig iron. Uh. It's the stuff that the Darbies were making in their iron works. It has the same high carbon content around three to four percent as pig iron does. Now, there a lot of examples of stuff made from cast iron. Cast Iron skillets are probably my favorite version of something

made from this material. And you would typically make a cast iron object by pouring the iron into a mold and allowing it to cool in that shape. And the reason you would want to do that is because cast iron is hard and it's brittle, which makes it very difficult to shape even when you heat it up. So if you pour the molten material into a mold so that it takes whatever shape you want and let it cool,

you're in good shape. But if you let it cool at all and then you try and work with it, it tends to break, It tends to resist being being shaped, so it's not terribly useful. In that case. Um. So that's why it's called cast iron. It's best used if you cast it into molds. Cast iron, by the way, is also prone to rust, which made it less useful for material that was constantly exposed to the elements or was in damp areas. Now the next type of iron is wrought iron. To you are o U g HT

wrought iron like a wrought iron fence. We produce wrought iron by taking pig iron and heating it up again in a different type of iron works called a finery. Now you'd heat the pig iron up to the liquid point and mix it with other slag materials, which lowers the carbon content. By introducing non carbon material you create a new alloy and the overall percentage of carbon is reduced. As a result, wrought iron is easier to work with than cast iron, and it's not as susceptible to rusting.

Wrought iron ended up becoming the most important type of iron in the Industrial Revolution until people finally figured out how to make steel on a consistent and large scale basis. So wrought iron ended up being really the king of iron once people were able to do it on a large enough and consistent enough basis. So what's the big deal with steel? I mean, why wasn't Why wasn't steel the material of choice? Well, steel is just another alloy of iron. First of all, it's not like it's a

totally different material. It's an alloy. It has less carbon in it than other types of iron, like I mentioned before, less than two and sometimes has other materials mixed in to create the steel. Different types of steel used different materials mixed in with the iron, and it gives it various properties. People have been making steel in small amounts for centuries. It's not like it was brand new in the Industrial Revolution. But it was a laborious process and

it was easy to mess up. You could make errors that would produce iron rather than steel. For a long time, people weren't entirely uh certain of the what was causing the output to be steel versus iron. Sometimes they just thought, oh, well, this was a good batch of iron, or not realizing that the process they were using, or the materials they were, the fuel they were using, the materials they were mixing

with it, we're actually making a huge difference. It took a long time of experimentation to figure out the right approach. One man who improved steel making techniques was Benjamin Huntsman, who opened a steel plant in Sheffield, England, in seventeen forty. His steel was kind of controversial actually at the time. His fellow countrymen considered the steel to be too hard

to be useful. These were people called cutlers, who would take the steel produced by someone like Huntsman and then try and shape it into useful tools, often cutting tools. That was the main use of steel for a really long time. But the cutlers said, no, the steel is too hard, it's not any good. However, Huntsman began to form relationships with cutlers who were in Europe, not in England, so in mainland Europe, and they began to rely heavily on his steel and he started to do a lot

of business. Well. England at the time was incredibly protective of its various industries. They wanted to preserve their dominance in as many areas as possible, including textiles and iron and uh and later on steam power. So because of that, the cutlers in England began to reconsider their feelings about the difficulty of working with Huntsman Steele, so they began to use it as well. Now Huntsman tried to keep

his methods a secret. He was one of those people who decided never to patent his processes because he wanted to try and maintain full control over them. However, one of his competitors named Samuel Walker, found out how Huntsman

was making his steel and began to copy him. According to report, Walker's work was never quite as good as Huntsman's, but his steel was also sought after, and so soon this technique of making steel began to spread outward and more iron workers began to experiment making steel, but at this stage they were still making it in fairly small amounts. By the seventeen seventies, the iron industry in Britain was booming.

Coke was the fuel of choice by this point, so this was decades after Darby had first started using coke as fuel, and by the seventeen seventies now everybody was really onto this and many iron works were in production at the time. In Plymouth, a man named Henry Court bought a small iron works just outside the city and began to experiment with new methods of producing wrought iron, and his experiments led to what was called the puddling process.

Now This approach a little tricky to explain, particularly without the use of visual aids. It involved heating refined iron in a furnace. So you would first have to take iron ore and smelt it through one of the processes that talked about earlier, and then the refined iron you would get from that process would be used as the main ingredient for this new process. So you would take this refined iron uh and put it in a furnace and mix it with some iron oxides on purpose and

stir the molten material using these very long rods. And the rods had hooks on the end. And we're called either puddling bars or rabble rebbels. So I guess like the hamburglar. He says, rabble rabble right. Well, anyway, they were called rebbels. You would have a worker hold one of these long bars. Uh. They would sometimes be called rabblers. This is not a joke. They really were uh. And of course you couldn't put them inside the furnace they

would burn up and die. So what they would do is they use these working doors that were built into the sides of the furnace that would allow you to

pass a rod through the door. Into the furnace itself so that you could stir the molten material from a safe distance UH and the rattlers would stir this mixture as they would continue to blast air at the mixture, and that would allow oxygen to react with the iron oxides in the molten material, and impurities would form slag that again would float on top of the iron or would vaporize into gases that could be vented out of

the top of the furnace. During this process, carbon would begin to burn off in the iron, and as the carbon burns off, the melting temperature of the iron increases. So, in other words, in order to keep that iron molten, you would have to increase the temperature in the furnace. And this is because the impurities that the carbon in this case is getting burnt off, and the melting point for pure carbon is higher than the melting point of

or not pure carbon, but pure iron. The melting point of pure iron is higher than it would be with an iron carbon mix. So that meant that you had to continue to increase the temperature in the furnace. You would have to add more fuel to make the temperature go higher, and you would continue to do this process until you've burned off enough carbon so that the mixture itself begins to change. It uh in in puddling terms,

it comes to nature. Now that means that the the iron itself has very different qualities, and by change, I mean it stops being a molten liquid instead becomes kind of a spongy mass of iron. So it's still shapeable, it's still very you know soft compare too solid iron,

but it's no longer in liquid form. And it's at that point that the rabblers would have to hook the masks using the rabbles or the puddling bars, and once hooked, they then have to pull out these masses, these these puddles or puddle balls rather of iron, which were incredibly heavy. We're talking like eighty pounds or more. And they would grab the stuff with the bar, pull it out of the furnace and then take the puddle balls. They're still

incredibly hot to some massive hammers. Now, originally those hammers were manually wielded by people who were known as shinglers um, but eventually they would be used with the water and steam powered hammers instead of manual labor, which was good because being a shingler was it was it was a specialized skill, but it also usually meant you didn't live very long. You had a very strenuous, difficult job with

a high degree of danger to it. So the process of hammering the puddle balls would put them into a shape that resembled roof shingles, which is where the process kind of got its name is shingling. And you would do shingling not just to get the iron into a new shape. It was actually meant to hammer out slag and other impurities, and also to hammer out cracks that

were inside the mass. So slamming a hammer against this puddle ball would create uh, you know, smushed the iron together so that that cracks would be would be completely sealed and once heated, or once shingled rather, you would then heat the iron again until it was malleable and then roll it out into bars of wrought iron or sometimes in the poles of iron. Uh. Quartz process sped up the production of of making wrought iron consider toerably,

and he patented the approach in the seventeen eighties. So by Courts time, iron was beginning to become the material of choice for tools and for industrial machines, largely replacing wood, which had previously been the material of choice. So if you look at machines previous before, before like seventeen seventeen, you know, really seeing a lot of wood uh components. You know, even gears and things often would be made

of wood rather than iron. Some cast iron was being used in gears and some other uh parts of machinery, but wood was largely the main material, with stone being used for foundations and things like that, for things like mills and that sort of stuff. But now by courts time, iron has become the really important material for tools, industrial machines.

It's uh, it's really taking off. And looking at the amount of iron produced in England during these decades of the Industrial Revolution, you can see how these improvements in technology really made a huge impact. So here's an example. Just before the era of the Industrial Revolution, in seventeen forty, Britain was producing about seventeen thousand tons of pig iron

per year. By seventy eight that Amountain had increased to nearly seventy thousand tons, So seventeen thousand to seventy thousand, and by seventeen ninety six, you know, it's not even a full decade later it was producing more than a hundred twenty five thousand tons of pig iron and that number would just continue to grow over the next century.

So by the mid nineteenth century you're talking an enormous amount of iron being produced out of out of Britain, and it was being used in construction to make bridges and tunnels and iron rails. So the rails actually predated locomotives and trains. The rail system was men to allow carts to pass easily over land. Uh special cards would be pulled by horses or other animals, and it would be a while before the first steam powered train would pull carts along rails, but the rail system in general

made it much easier to transport goods over land. Meanwhile, there was also a lot of work in creating transportation lanes over water. As I mentioned in the last episode, Britain was really well positioned for the Industrial Revolution for a lot of reasons, and one of them is that it has a lot of port cities. So shipping was

a big part of British industry. But within the countries of Britain, within England and Wales and Scotland in particular, it was really important to try and ship various materials between cities, and that meant creating special waterways, including canals, to connect rivers together that otherwise wouldn't easily meet. So there were a lot of canals, but one really impressive iron structure was the Potka Sulta Aqueduct, also known as

the Stream in the Sky. Now that name is Welsh, if you could not guess before, and that means I've probably butchered the pronunciation, as the Welsh believed language is something no one should ever be able to actually speak. But this aqueduct was a raised waterway that allowed this canal to cross over a valley. Now, the goal here was to have a canal connecting two different rivers together, but there was a valley in the way, and how would you get the water to cross over the valley.

You could build a series of locks which would allow you to very slowly lower or raise a barge in a series of stepped approaches, But that takes a lot of time. It's not terribly afici and if you want to get a lot done so Instead, there was a guy named Thomas Telford who proposed this raised aqueduct that would bypass the valley entirely by going over it. So essentially you're looking at a big iron trough and that

holds all the water. Use arch stone pillars to support the trough, and you can see pictures of this or video even of this particular aqueduct, and it is pretty amazing to look at. So a barge could float down the canal and over the aqueduct without having to descend into the valley, and this saved a lot of time. Now, Telford's original design was met with a lot of skepticism, but he was allowed to build it and it ended

up working out just fine. So it was a big success in the Industrial Revolution and really proved how far the the industry had come as far as iron production and making sure it is reliable and safe. And it also added a lot of confidence to areas like architecture for everything from bridge building to tunnels and stuff like that.

We will continue our story about the Industrial Revolution after we take this break for some ads, it wasn't until eighteen fifty six that the steel industry really took off. That's when a man named Henry Bessemer came up with a method to produce steel in large amounts. So before the most reliable processes would only produce small amounts of steel over time, which made steel difficult to produce in quantities large enough for it to meet demand, and it

also meant that the price was really high. But Bessemer came up with a lot of improvements. So Bessemer's father was an engineer, and Bestmer himself took after his dad. He was largely self educated and learned about engineering by observing his father's work and doing his own experiments. He generated an enormous fortune before ever getting into the steel business by producing a type of powder that was used in gold paints, and at the time, gold paints were

in really high demand in Britain and in Europe. So he made a fortune off that and then used that to fund his other experiments. He also created a machine designed to crush sugarcane, but it was in the steel industry that he became a legend. So Bessemer was trying to create a harder type of iron, and it was all out of necessity. It's kind of a funny story.

He had developed a type of artillery shell and he was trying to sell it to the French, but the French were looking at his his artillery shell, and they said, we can't take this because our cannons are made out of cast iron and they wouldn't be strong enough to fire this artillery shell without exploding, which in war would

be not an incredibly effective tactic. So Bessemer decided that the best way to solve this problem would be to create a stronger type of iron so that the French could make their cannons out of that, and then he could sell the shells he had created to them. So it was a roundabout way of doing things, but ended up working out pretty well. So Bessemer started by using a blast furnace much like the one I've already described

earlier in this episode. As he experimented, he found that oxygen in the furnace would remove some of the carbon from the pig iron that he was using. Inside the furnace, Blowing air through the purified iron caused it to heat up more, and the oxygen was heating up the remaining carbon inside the the melted iron as well as silicon, and this made the resulting molten material easy to pour,

and the process became known as the Bessemer process. The result was that you would get these slag free ingots of metal. Combining this approach with a discovery from another engineer named Robert Forrester Mushnitt, Bessemer could use an iron manganese alloy to remove extra oxygen from the decarborized iron, and this is what allowed him to create steel. Now, Bessemer hit a snag when he discovered his process really

only worked if he used phosphorus free iron ore. So if you remember I mentioned, materials like phosphorus and sulfur turn iron brittle, so it becomes less useful, it'll shear off. And Bessemer was just by chance using iron ore that didn't have a high phosphorus content. So when he was doing his experiments, everything was coming out great. But then when iron workers at large began to try his very process, they started getting very different results because much of that

iron ore in Britain contained phosph us. Bessemer found the source of iron ore in northwestern England that was free of phosphorus, but that solution wasn't ideal because it meant that you had to get all your iron ore from one place. Now, another improvement in eighteen seventy seven made

Bessemer's approach more useful. There was a another person named Sydney Gilchrist Thomas who created a furnace lining that removed phosphorus from the iron ore as it was heating up, which meant that iron workers didn't have to rely exclusively on that phosphorus free iron ore from Northwest England. The

end product of this process was called mild steel. Now it's called mild steel because it was different from the steel produced by the earlier methods, the kind that that court was known for, because it didn't it wasn't it wasn't as hard, it wasn't only useful for cutting tools, which is pretty much what all the hard steel was used for in earlier versions. It was easier to work and became the material of choice for applications like girders, rods, wires, rivets,

and other uses. So while iron had replaced wood earlier, now steele was beginning to replace iron. In the late eighteen sixties, there was a new process called the open hearth process that rivaled the Bessemer approach. Now, this technique was created by a German engineer living in England and his name was William Siemens. Siemens found a way to use the waist heat generated by a furnace to feed back into the furnace itself to increase the temperature inside

the furnace. So what you would do is that you would have this hot air being given off by the furnace and he would pump that air back into the furnace using that same pathway, which meant that the air being blasted into the furnace was already preheated, so it was no longer the cold air blast. This is a hot air blast that in turn made the flame temperature hotter and using a combination of pig iron and scrap wrought iron, iron workers could use this technique to produce

steel quickly. William Siemens would go on to invent the electric furnace in eighteen seventy nine, which provided another enormous boost to the steel industry in England. He also worked in electric telegraphy and in lighting, so this is also

the era where people are experimenting with those technologies. Uh. William Siemens and Henry Bessemer both were knighted for their contributions to Britain, so that was very interesting because William Siemens, obviously he was German born, but became an English citizen and became a knight, and Bessemer was a self taught man who became a knight. So very interesting that both of them were able to create such important contributions to the entire nation. Stay tuned for the exciting conclusion of

this tex Stuff classic episode right after we take this break. Now, both the best simer process and the open hearth process significantly reduced the amount of time it took to convert iron into steel, and that created a new industry in Britain. Before long, steel replaced iron and all those applications, just as iron had replaced wood back in the eighteenth century. But now we've got to backtrack a little bit to

talk about steam engines. So all that's going on with the iron and steel industry from the seventeen forties up until the late eighteen hundreds, but steam engines actually go back before the Industrial Revolution. Now, in October two thirteen, tech Stuff did a full episode about steam engines and how they work. So I'll try to be brief because you can always go back and listen to that episode for a more detailed account of how steam engines came

about and the developments over time. But here's a submarine. First of all, we've known about steam for quite some time. The ancient Greeks were aware of steam's ability to do work, but it wasn't really until the Industrial Revolution that anyone made real practical steam engines. And part of the reason

for that is that steam is incredibly dangerous. Not only can it be hot enough to cause devastating burns, but if you want it to do useful work, you have to put it under pressure, and that means you have to have materials strong enough to deal with that pressure to contain the steam without failing, because if there is a failure, your device is going to fly apart, and what you've really created is a steam powered bomb, not

entirely useful for industry. So it took a long time for engineers to figure out ways to harness steam in a way that wasn't inherently dangerous every time you used it. The development of the early steam engines actually predates the Industrial Revolution. In sixt a guy named Thomas Savory patented a device meant to draw water from mines using steam, and it would allow mining operations to continue. It worked on the principle of vacuum power, so the device would

fill a chamber with steam. You would have a boiler. So you've got essentially a pot filled with water, and you put heat to the pot. The water begins to boil and gives off steam. Uh, there's a pipe leading from the pot to a chamber, so the chamber fills up with steam until you've got a nice amount of steam built up inside that chamber. You would then cut

off the pathway between the chamber and the boiler. There would be another line leading from the chamber down into a mine, and the end of the line would be under the water level. As the steam cools, it condenses, and when it condenses, it's taking up less space, which is creating a vacuum that's negative pressure. So this vacuum would start to pull the water from the pipe. You know, the water that's in the mine that there's an end of a pipe that's underneath that water level, would pull

water up the length of that pipe into the chamber. Now, once you've got a chamber filled with water, you have to get rid of that water, and often the way they would do that is they would close off the pathway down the pipe that goes down into the mine and heat it up and then expel the water with using steam power. Sometimes they would go upwards of eighty feet, or sometimes it would explode. Even if it worked properly, the invention had pretty tough limitations. It was really limited

to shallow depths. You couldn't go very deep with this because the vacuum power wasn't strong enough to pull water up more than a few or so comparatively speaking to other types of pumps. Then alone came a guy named Thomas Newcomen who would come up with a significant improvement over savories approach, and he used a steam powered water pump. Now, the best way to imagine this is imagine a giant seesaw. Alright, one end of the seesaw is weighted down, so it's

naturally in the down position at any given time. That's the pump end. That's the end that is attached by a chain to a pump that is designed to pull water up from underground. The other end of the pump, which is up in the air, is attached by a chain to a steam piston inside a cylinder. So you've got a cylinder and a piston. The piston is in the up position. It's dangling from the chain that's on the upper part of the seesaw. Now Newcomman's invention would

fill the cylinder with steam. Again, you would have a boiler that would boil water generate steam. Steam would fill this cylinder up, and then you would cool the cylinder cylinder down, which would cause the steam to condense, creating a vacuum, and that vacuum would pull on the piston. So you have a pulling force that would pull on the upper end of the seesaw, pulling it down, making the lower end of the seesaw go up and pump water out of the mine. So again it's using steam

as a vacuum source, not as a pushing source. It was never used to push in those early steam engines, only to pull, and that was largely because the materials being used to create the cylinders and boilers weren't strong enough to hold steam under greater pressures. So it was just too dangerous to create a steam engine that you steam as a pushing power. At that time, it made way more sense to create the pulling power because it

was much less dangerous. Now new Cummins invention worked, but it was inefficient, and that's largely because it required you to heat the cylinder that has the piston in it. You have to heat it up and then you have to cool it down, and you have to heat it up and cool it down over and over again, which meant that you had to expend a lot of extra energy just to get the cylinder at the right temperature

each time. And it also meant that heating it up and cooling it down would create a lot of stress on the material, so you'd have to replace the cylinder fairly regularly, because if you kept doing it indefinitely, it would become too weak to operate safely. But that all changed when a fellow named James Watt came around. James Watt invented a device called a condenser in seventeen sixty five.

So the condenser was a pretty simple idea. It was a separate chamber that allowed steam to condense, and by creating a separate chamber, you didn't have to change the temperature of the cylinder anymore. You just kept the cylinder at a high temperature. You didn't have to lower it at all because once the steam was created in the cylinder, it could pass into the condenser chamber, cool down and create that vacuum poll. So this was a huge improvement

on the efficiency of the newcoming engine. So what really made a big contribution here, now, late in his career, what would make something else that he was even more proud of. He thought that this was his most important invention out of everything he did. It was a solid mechanism that allowed the up and down motion of the piston to translate into the arc motion of that see saw pump I was talking about. Now, As I mentioned, earlier models used a chain to connect the pump to

the piston. And there's a limitation right there, right because if you have a chain, you can only pull. You can't push a chain or a rope. If you try and do that, you don't get any useful work out of that. But by the late seventeen hundreds, you could actually create materials strong enough to contain steam under a

decent amount of pressure. So what created this solid mechanism instead of a chain that would connect the end of a of a of a pump, you know, the the working in not the not the pumping end, but the other end to the piston. And because it was solid, it could push or pull, and the up and down motion of the piston was translated into this arc motion of the pump going see sawing back and forth, and that meant that you could actually use the piston to

push and to pull. So by pumping steam into the cylinder, you could push the piston up, and by allowing the steam to condense, you could pull the piston back down. That meant you created a double acting piston. And this meant that you could make a steam engine much more

efficient because it could work in both directions. Now, the steam engine had an enormous impact on both the textile and the iron industries, so that's kind of why I put it here at this point to talk about how it affected the other two industries I've already covered in this series. So factories began to use steam power in place of water wheels, or in addition to water wheels. Steam power freed up factories from having to be placed

alongside a river. You could actually put a factory anywhere by creating steam engines to provide the power for whatever it was you were doing. So there were steam powered looms and textile mills, and steam powered blowers and iron works, so you didn't have to have the river to provide the water wheel power or You could even use a steam engine to pull water to continuously supply the water wheel with enough water to turn and provide the mechanical

power that you needed. So there were combinations as well. Harnessing steam made these industries more efficient, and that led to lower prices on goods, and it also increased a need for workers. You began to be able to produce more, but you needed more people to work on the stuff you were doing. And that was great news for the population of Britain because the population was growing and there

weren't enough jobs to go around otherwise. So this was creating a demand for jobs um and there were plenty of people to fill those jobs. And the Industrial Revolution was producing something besides just iron and cloth. It was producing the working class. Now that kind of leads me to the conclusion of this episode. There's a lot we could talk about with steam, obviously, including the development of the locomotive and steamships, but I'm going to save that

for the final episode. So I'm going to conclude the series on the Industrial Revolution with the next one, and we'll look at how transportation was changing, including those steamships

and locomotives. We'll talk about some of the conflicts that were going on around the same span of time, So that includes the American Revolution that took place during the Industrial Revolution in England, as well as the Napoleonic Wars and the American Civil War, and there were other conflicts as well, so that was a big part of what

was driving innovation as well. It became necessity for the war efforts to create iron and steel products more efficiently and as well as textiles and other elements as well. So that's gonna be part of the discussion in the next episode. I hope you enjoyed that classic episode of

tech Stuff. Next week we will wrap up this three part series and uh in the meantime, if you have suggestions for topics I should cover in future episodes of tech Stuff, whether it's a look back on big historical trends in tech or something that's cutting edge and brand new. You can do that in a couple of different ways. One is to download the I Heart radio app. It is free to download and to use. You can navigate over to tech Stuff using the little search bar. You'll

see that there is a microphone icon. Let's you leave a voice message up to thirty seconds in length. Letting me know what you would like on on the show, or if you would prefer an alternative. You can always use Twitter and you can send me a tweet. The handle for the show is text Stuff hs W and I'll talk to you again really soon. Tech Stuff is

an I heart Radio production. For more podcasts from I Heart Radio, visit the i heart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.