November 25, 2015 • 55 mins
As we continue to explore the Industrial Revolution, we look at how iron helped shape the modern world. It's time to explore iron, steam engines and more!
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Episode Transcript
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Speaker 1 (00:04):
Get technology with tech Stuff from stolom. Hey there, and
welcome to Tech Stuff. I'm your host, Jonathan Strickland. Now,
in our last episode, we started to look at the
beginning of the Industrial Revolution, which started in England in
(00:25):
the mid eighteenth century. Though, as I mentioned in that
previous episode, it's actually really hard to point at any
historical event, not just the Industrial Revolution, but really any
big event and definitively carve out exactly when it began,
because history just doesn't work like that. Things develop and
bleed into one another. But at any rate, generally speaking,
(00:48):
we tend to look at seventeen seventeen fifties somewhere around
there as the beginning of the Industrial Revolution. 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 weavers that would
(01:10):
do you know, maybe a couple would work together, uh,
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
(01:30):
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,
(01:52):
the fe stuff to build anything of any significance. And
that's because of a couple of things. 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
(02:14):
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.
(02:35):
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
(02:57):
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
(03:19):
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
(03:40):
oxydizes so quickly. Instead, we mind 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 load stone,
among others. There are a few other versions of iron
(04:03):
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
(04:25):
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
(04:47):
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 that was using from Sweden. The
iron from Sweden did not have the high concentrations of
(05:10):
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
(05:30):
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.
(05:51):
Sometimes it's another metal, sometimes it's a different substance. But
these are chemical mixtures that have their own features that
are a front 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
(06:13):
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 percent of carbon in the alloy, and mixing other
metals or substances will create different types of steel or iron.
(06:35):
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
(06:58):
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
(07:19):
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
(07:43):
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
(08:04):
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
(08:29):
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
(08:52):
were mostly located in forests because it was cheaper to
ship the iron ore and iron from the iron work
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
(09:14):
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
(09:35):
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,
(09:56):
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 when
burned would mix with a 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
(10:19):
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
(10:41):
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,
(11:02):
the information on how you do something becomes public knowledge
and eventually passes into the public domain. So rather 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
(11:23):
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
(11:46):
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 to thirty ft square at the base. Often built
(12:06):
into the side of a hill. So that way, 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
(12:29):
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
(12:50):
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 uh mixed 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 in the iron ore itself.
(13:13):
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,
(13:34):
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
(13:55):
into the furnace and what we're called blasts. The earliest
blast furnaces where 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,
(14:17):
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
(14:38):
the devices made to actually blow air into a an area,
usually some form of furnace or fire that would provide
the blast 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
(15:00):
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.
(15:23):
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
(15:44):
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,
(16:07):
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 the 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
(16:29):
gases that are rising up through this cylinder, and the
material passes through those hot gases getting hot before they
even get toward the heart 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
(16:51):
oxide that was locked away inside the iron ore. Now
this is a process called reduction. And while 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
(17:12):
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,
(17:35):
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,
So that molten iron would then run through a channel
(17:57):
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
(18:18):
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
(18:40):
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.
(19:02):
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
(19:24):
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 are a lot
(19:46):
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
(20:08):
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,
(20:32):
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
(20:54):
is wrought iron w r o U g HT wrought
eye 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
(21:16):
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
(21:40):
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 steel the material
(22:01):
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
(22:23):
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 can make errors that would produce
iron rather than steel. For a long time, people weren't
(22:45):
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 material else
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
(23:08):
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,
(23:31):
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
(23:53):
began to form relationships with cutlers who were in Europe,
not in England, so in 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,
(24:16):
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
(24:36):
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 reports, Walker's work was never quite as good
(24:59):
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
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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
(25:44):
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 is a
little tricky to explain, particularly without the use of visual aids.
It involved heating refined iron in a furnace. So you
(26:04):
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
(26:29):
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 rabbels. You would have a worker hold
one of these long bars. Uh. They would sometimes be
(26:50):
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
(27:10):
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
(27:31):
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,
(27:54):
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
(28:15):
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,
(28:36):
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 compared to solid iron,
(28:59):
but it's no longer in lick would 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.
(29:21):
And they would grab this 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
(29:43):
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 high degree of danger to it. So
(30:04):
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
(30:24):
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
(30:47):
iron or sometimes in the poles of iron. Uh. Quartz
process sped up the production of of making wrought iron considerably,
and he patented the approach in the seventeen eight ease.
So by Courts time, iron was beginning to become the
material of choice. For tools and for industrial machines, largely
(31:09):
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
(31:29):
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.
(31:53):
And looking at the amount of iron produced in England
during these decades of the Industrial Revolution, you can see
how these improvements and 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
(32:15):
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
(32:38):
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 meant to allow carts to pass easily over land.
(33:00):
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 cards 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
(33:22):
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
(33:45):
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
impress of iron structure was the Potka Sulta Aqueduct, also
known as the Stream in the Sky. Now that name
(34:08):
is Welsh, if you could not guess before, and that
means I've probably butchered the pronunciation, as the Welsh believe
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
(34:31):
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
(34:54):
a lot of time. It's not terribly efficient if you
want to get a lot done so and dead. 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
(35:14):
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
(35:34):
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
(35:55):
and making sure it was 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. Now,
it wasn't until eighteen fifty six that the steel industry
really took off. That's when a man named Henry Bessemer
(36:17):
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 Bessemer himself took after
(36:42):
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.
(37:04):
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
(37:26):
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
(37:50):
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
(38:11):
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 melted iron, as well as silicon, and
(38:35):
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 R. Mushnitt. Bessemer could use an iron manganese
alloy to remove extra oxygen from the decarburized iron, and
(39:00):
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
(39:23):
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 phosphorus. Bessemer found the source
of iron ore in northwestern England that was free of phosphorus,
(39:47):
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.
Uh there was a another person named Sydney Gilchrist Thomas
who created a furnace lining that removed phosphorus from the
(40:08):
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,
(40:31):
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 steel was
(40:54):
beginning to replace iron. In the late eighteen sixties, there
was a new process US 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
(41:18):
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
(41:40):
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 E nine, which provided another enormous boost to the
(42:00):
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
(42:23):
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. Now,
both the Bessemer 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.
(42:46):
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
(43:07):
back before the Industrial Revolution. Now, in October two thirteen,
text 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 the submarine.
(43:28):
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
(43:49):
if you wanted to do useful work, you have to
put it under pressure, and that means you have to
have material strong enough to deal with that pressure to
contain the steam without fay link, 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
(44:09):
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 a guy named Thomas Savory patented a
(44:31):
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
(44:53):
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,
(45:17):
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
(45:37):
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
(45:58):
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
(46:20):
because the vacuum power wasn't strong enough to pull water
up more than a few feet 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
(46:41):
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
(47:02):
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.
(47:25):
Now new Cooman'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
(47:48):
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
(48:08):
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 Newcoming's invention worked,
but it was inefficient, and that's largely because it required
(48:32):
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
(48:55):
fairly regularly because if you kept doing it indefinitely, it
would become too week 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
(49:15):
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
(49:36):
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
(49:57):
mechanism that allowed the up and down most 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
(50:17):
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
(50:38):
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
(50:58):
of the pump going seesawing 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
(51:21):
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've
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
(51:44):
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,
(52:05):
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
(52:27):
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
(52:50):
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
(53:13):
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
are 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
(53:34):
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 a 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, and we'll also explore the development of the
(53:58):
working class, the condition ends that workers experienced and how
that pushed us into the modern era largely because of
what technology was allowing us to do. And it wasn't
all good. It was. Some of it was pretty grim.
We're gonna get into some some rough stuff in the
next episode. But if you guys have suggestions for future
(54:18):
episodes of Tech Stuff, you should let me know, and
it could be about the technology or a process or
a company or personality in tech. And also if you
have suggestions for any interview subjects you would like me
to talk to or people you would like to have
on the show as a guest host dropped me a line.
My email address is text Stuff at how Stuff Works
(54:41):
dot com, or you can contact me on Facebook for Twitter,
I've gotten to handle text stuff. HSW, and I'll talk
to you again really soon for more on this and
bathans of other topics because it has to. What's that coming, really, really,
Get technology with tech Stuff from stolom. Hey there, and
welcome to Tech Stuff. I'm your host, Jonathan Strickland. Now,
in our last episode, we started to look at the
beginning of the Industrial Revolution, which started in England in
(00:25):
the mid eighteenth century. Though, as I mentioned in that
previous episode, it's actually really hard to point at any
historical event, not just the Industrial Revolution, but really any
big event and definitively carve out exactly when it began,
because history just doesn't work like that. Things develop and
bleed into one another. But at any rate, generally speaking,
(00:48):
we tend to look at seventeen seventeen fifties somewhere around
there as the beginning of the Industrial Revolution. 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 weavers that would
(01:10):
do you know, maybe a couple would work together, uh,
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
(01:30):
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,
(01:52):
the fe stuff to build anything of any significance. And
that's because of a couple of things. 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
(02:14):
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.
(02:35):
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
(02:57):
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
(03:19):
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
(03:40):
oxydizes so quickly. Instead, we mind 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 load stone,
among others. There are a few other versions of iron
(04:03):
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
(04:25):
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
(04:47):
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 that was using from Sweden. The
iron from Sweden did not have the high concentrations of
(05:10):
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
(05:30):
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.
(05:51):
Sometimes it's another metal, sometimes it's a different substance. But
these are chemical mixtures that have their own features that
are a front 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
(06:13):
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 percent of carbon in the alloy, and mixing other
metals or substances will create different types of steel or iron.
(06:35):
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
(06:58):
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
(07:19):
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
(07:43):
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
(08:04):
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
(08:29):
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
(08:52):
were mostly located in forests because it was cheaper to
ship the iron ore and iron from the iron work
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
(09:14):
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
(09:35):
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,
(09:56):
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 when
burned would mix with a 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
(10:19):
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
(10:41):
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,
(11:02):
the information on how you do something becomes public knowledge
and eventually passes into the public domain. So rather 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
(11:23):
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
(11:46):
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 to thirty ft square at the base. Often built
(12:06):
into the side of a hill. So that way, 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
(12:29):
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
(12:50):
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 uh mixed 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 in the iron ore itself.
(13:13):
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,
(13:34):
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
(13:55):
into the furnace and what we're called blasts. The earliest
blast furnaces where 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,
(14:17):
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
(14:38):
the devices made to actually blow air into a an area,
usually some form of furnace or fire that would provide
the blast 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
(15:00):
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.
(15:23):
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
(15:44):
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,
(16:07):
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 the 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
(16:29):
gases that are rising up through this cylinder, and the
material passes through those hot gases getting hot before they
even get toward the heart 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
(16:51):
oxide that was locked away inside the iron ore. Now
this is a process called reduction. And while 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
(17:12):
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,
(17:35):
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,
So that molten iron would then run through a channel
(17:57):
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
(18:18):
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
(18:40):
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.
(19:02):
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
(19:24):
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 are a lot
(19:46):
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
(20:08):
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,
(20:32):
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
(20:54):
is wrought iron w r o U g HT wrought
eye 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
(21:16):
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
(21:40):
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 steel the material
(22:01):
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
(22:23):
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 can make errors that would produce
iron rather than steel. For a long time, people weren't
(22:45):
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 material else
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
(23:08):
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,
(23:31):
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
(23:53):
began to form relationships with cutlers who were in Europe,
not in England, so in 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,
(24:16):
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
(24:36):
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 reports, Walker's work was never quite as good
(24:59):
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
(25:21):
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
(25:44):
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 is a
little tricky to explain, particularly without the use of visual aids.
It involved heating refined iron in a furnace. So you
(26:04):
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
(26:29):
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 rabbels. You would have a worker hold
one of these long bars. Uh. They would sometimes be
(26:50):
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
(27:10):
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
(27:31):
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,
(27:54):
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
(28:15):
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,
(28:36):
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 compared to solid iron,
(28:59):
but it's no longer in lick would 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.
(29:21):
And they would grab this 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
(29:43):
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 high degree of danger to it. So
(30:04):
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
(30:24):
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
(30:47):
iron or sometimes in the poles of iron. Uh. Quartz
process sped up the production of of making wrought iron considerably,
and he patented the approach in the seventeen eight ease.
So by Courts time, iron was beginning to become the
material of choice. For tools and for industrial machines, largely
(31:09):
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
(31:29):
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.
(31:53):
And looking at the amount of iron produced in England
during these decades of the Industrial Revolution, you can see
how these improvements and 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
(32:15):
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
(32:38):
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 meant to allow carts to pass easily over land.
(33:00):
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 cards 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
(33:22):
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
(33:45):
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
impress of iron structure was the Potka Sulta Aqueduct, also
known as the Stream in the Sky. Now that name
(34:08):
is Welsh, if you could not guess before, and that
means I've probably butchered the pronunciation, as the Welsh believe
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
(34:31):
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
(34:54):
a lot of time. It's not terribly efficient if you
want to get a lot done so and dead. 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
(35:14):
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
(35:34):
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
(35:55):
and making sure it was 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. Now,
it wasn't until eighteen fifty six that the steel industry
really took off. That's when a man named Henry Bessemer
(36:17):
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 Bessemer himself took after
(36:42):
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.
(37:04):
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
(37:26):
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
(37:50):
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
(38:11):
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 melted iron, as well as silicon, and
(38:35):
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 R. Mushnitt. Bessemer could use an iron manganese
alloy to remove extra oxygen from the decarburized iron, and
(39:00):
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
(39:23):
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 phosphorus. Bessemer found the source
of iron ore in northwestern England that was free of phosphorus,
(39:47):
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.
Uh there was a another person named Sydney Gilchrist Thomas
who created a furnace lining that removed phosphorus from the
(40:08):
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,
(40:31):
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 steel was
(40:54):
beginning to replace iron. In the late eighteen sixties, there
was a new process US 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
(41:18):
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
(41:40):
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 E nine, which provided another enormous boost to the
(42:00):
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
(42:23):
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. Now,
both the Bessemer 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.
(42:46):
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
(43:07):
back before the Industrial Revolution. Now, in October two thirteen,
text 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 the submarine.
(43:28):
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
(43:49):
if you wanted to do useful work, you have to
put it under pressure, and that means you have to
have material strong enough to deal with that pressure to
contain the steam without fay link, 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
(44:09):
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 a guy named Thomas Savory patented a
(44:31):
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
(44:53):
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,
(45:17):
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
(45:37):
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
(45:58):
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
(46:20):
because the vacuum power wasn't strong enough to pull water
up more than a few feet 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
(46:41):
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
(47:02):
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.
(47:25):
Now new Cooman'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
(47:48):
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
(48:08):
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 Newcoming's invention worked,
but it was inefficient, and that's largely because it required
(48:32):
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
(48:55):
fairly regularly because if you kept doing it indefinitely, it
would become too week 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
(49:15):
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
(49:36):
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
(49:57):
mechanism that allowed the up and down most 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
(50:17):
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
(50:38):
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
(50:58):
of the pump going seesawing 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
(51:21):
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've
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
(51:44):
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,
(52:05):
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
(52:27):
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
(52:50):
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
(53:13):
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
are 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
(53:34):
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 a 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, and we'll also explore the development of the
(53:58):
working class, the condition ends that workers experienced and how
that pushed us into the modern era largely because of
what technology was allowing us to do. And it wasn't
all good. It was. Some of it was pretty grim.
We're gonna get into some some rough stuff in the
next episode. But if you guys have suggestions for future
(54:18):
episodes of Tech Stuff, you should let me know, and
it could be about the technology or a process or
a company or personality in tech. And also if you
have suggestions for any interview subjects you would like me
to talk to or people you would like to have
on the show as a guest host dropped me a line.
My email address is text Stuff at how Stuff Works
(54:41):
dot com, or you can contact me on Facebook for Twitter,
I've gotten to handle text stuff. HSW, and I'll talk
to you again really soon for more on this and
bathans of other topics because it has to. What's that coming, really, really,
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Hosts And Creators
Oz Woloshyn
Karah Preiss
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