Saugus Ironworks

If you go up here to Saugus, Massachusetts, it was the first iron works in the United States. They have a blast furnace up there.

New England blast furnace built in the 1630s to solve Britain's energy crisis by exporting iron from a region that still had forests. The structural answer to the 1558 law.

So they decided to build in the new world some of those things, because over here we had forests still — the Indians had not cut them all down — and so the British came over to cut them all down. They built in New England in the 1630s something called the Saugus Iron Works. Anyone ever been to Saugus to see the ironworks? Go up to Saugus, right up here — you don't want to walk it, but it's only about 20 minutes away — and they have the Saugus Iron Works. They built a blast furnace. Why? Because we had wood. We were solving the energy crisis for Britain. They could make iron and ship it over there, and the foundries over there could make cannons. We had the energy source here, namely wood. Anyone ever been to Jamestown, Virginia? They had an industrial plant there. I haven't been there for 35 years, you've been there more recently than me. But in any case, they built a glass furnace in Jamestown, which 35 years ago you could go and watch them make glass. So again, there were trees in Virginia — they were running out of trees by royal decree in England.

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Established 1620s in response to English wood shortage. Failed within 10-20 years. Iron industry migrated to Chesapeake Bay (Northeast Forge 1735, principal forge 1724) for water power.

Time-marker — "the days of Saugus Ironworks" — to date the bullseye-glass era to the early 17th century.

Through the early part of the 17th century, the early 1600s, we had bullseye glass, in the days of Saugus Ironworks. In 1688, a company in France called Saint-Gobain — anybody heard of Saint-Gobain? About a 40- or 50-billion-dollar-a-year company now. One of the largest companies in France, centered in France. In 1688, they would take molten glass and pour it on a plate, and they would polish it, for mirrors. The mirrors still had a lot of distortion because they would throw the limestone and potash and silica sand into a big pot, and they didn't stir it well enough, and compositional differences made the light refract differently through different areas of the glass. It might be good for a mirror, which is what people wanted — they would silver the mirror, so they just wanted something flat. They would polish it, and they didn't have diamond to polish it, so they would use corundum, which is aluminum oxide. Very labor-intensive, but that's how Saint-Gobain got started.

Used twice — first to anchor the historical practice of mixing charcoal with iron ore, then as the physical site Tom walks the class through (the shaft furnace, the sand-floor pig-iron casting, the bellows and water wheel). The Saugus furnace is the central physical referent of §8.

Cast iron is more than 2 or 2.5% carbon, more than carbon steel, because cast irons are eutectic. If I look at the melting point, cast iron — you'd like to have something low-melting to make it easy to cast. They call it cast iron because if you took iron ore — where you weren't looking for carbon — you would mix it with coal. Or originally, if you go up here to Saugus Ironworks, they mixed it with charcoal, which is carbon, a wood source of carbon. When you do that and try to melt it, the carbon will alloy with the iron and form cast iron.

But in the meantime, they had landed over here in North America, and they found all kinds of forest. This is the Saugus Ironworks. You go up to Saugus, Massachusetts, about forty minutes away — they have a National Historical Park, and this is the Saugus Ironworks. It was around 1619, it operated till about 1632. This is the inside. You can take a tour. And it's here because you didn't have trees you could use in England. Down here — anybody been to Jamestown, Virginia, also one of the first colonies? In Jamestown, they have a glass factory. They have the Jamestown glassworks. This is the recreation of the glassworks, very similar to what we have in the basement of Building 4. They could have come here rather than going to Jamestown, but it was a transportation problem of how to get coal.

Early-American blast furnace; used as the baseline productivity datum (~3000 person-hours/ton circa 1600) in the productivity curve at §10.

This is another view of the Saugus Iron Works, an old picture of a blast furnace where people are using carbon reduction. At the top they're going to pour in limestone, iron ore, and charcoal. The guy will come and dump a wheelbarrow load of each one in succession, and you layer this thing up. You have a bellows over here. A lot of times it wasn't a person holding the bellows — they would have a paddle wheel or water wheel that would turn a bellows, so that you would have a blast of air. With the blast of air you can pump that temperature up a little bit, plus you're in a confined insulated space. Here's the brickwork at Saugus. They built it on a hill so they could be at different levels, and the casting floor is right down here, which is basically just a sandy floor. They cast the cast iron when they tap the furnace about once or twice a day, and it typically has to run continuously.

The historical baseline for steel productivity (4,000 person-hours/ton) and for early American cast iron production (frying pans, kettles, hand-forged nails).

When I was in the steel industry in 1975, six person-hours per ton. By the mid-'90s it was half an hour per ton — six times better in twenty years. Today it's less than twenty minutes a ton to make steel. If you go up to Saugus Ironworks, it was about 4,000 hours per ton — about one or two person-years of effort, cutting down the trees, making the charcoal, smelting it, all to get a lousy ton of cast iron, it wouldn't even be steel. So productivity in these industries has been tremendous over this period of time. Why? Necessity is the mother of invention. When you see that you're going to be extinct, you're going to lose your company, you start being willing to innovate.

Steel is made from three things: iron ore, limestone, and coal. At Saugus Iron Works they were cutting trees, not coal — making charcoal. But you need an energy source, and traditionally that was coal. In the bogs in Saugus they could get iron ore, and there's limestone all over New England. The limestone is the flux, the iron ore produces the iron, and the coal goes through coke ovens.

1630s wrought iron production, illustrating the inefficient pre-Bessemer process of heating, reheating, and oxidizing carbon out.

To make steel with fossil fuels, you have to preheat your steel. The Bessemer converter looks something like this. [Tom sketches.] You turn it halfway outside. You have the molten iron-carbon down here. You put cast iron in here, which is three or four percent carbon, and to make it into steel you've got to be less than one percent carbon — you've got to burn the carbon out. They knew they could do that, because they had made wrought iron for years by blowing oxygen in. But as you blow the oxygen in, the wrought iron's melting temperature increases, you get rid of your carbon, and it solidified on you. They made wrought iron up at Saugus Iron Works in the 1630s. But it was a very inefficient process of heating, reheating, getting the carbon out by oxidizing it away.

Origin of "pig iron" terminology (sow bar casting bed); 1630s establishment driven by England's wood-charcoal energy crisis; America's natural resource was trees. Used as a historical lead-in to why we have cast iron vs. steel.

Cranes and hooks and shackles, or five or six muscular people, to move that sow bar around. The little pig iron things — I can take those and remelt them and make cast-iron cooking utensils, or I can take them and forge them into nails or horseshoes or whatever. They still call it pig iron. They don't talk about the sow bars anymore, but that's where the term pig iron came from. After they let it solidify, five or six hours after they cast it, they would take the metal out of the sand mold, take it over to the Ford [Forge] Shop, then just rake the sand back and dig more holes for the next casting.

~1600s. One person-year per ton of steel produced — the baseline anchor for Tom's productivity chart. Manual charcoaling, manual ore mining, manual limestone, 60-hour weeks.

This is a chart I put together a few years ago. Back in the 1600s when they had Saugus Ironworks, it probably took about one person-year per ton. The guy had to go chop the trees, make charcoal out of the logs — you basically stack up the logs, cover them with straw and mud, and then you light the inside, and there's not enough oxygen so you burn off all the lignin in the logs, and you end up with — not coke, we call it charcoal, but it's like today's coke made from coal. So that was your carbon for your blast furnace. You then had to go get the iron ore, dig it out of the ground; you had to get the limestone, digging it out of the ground. When it's all manual work, it takes a lot of time. And then you've got to run your blast furnace. So I estimated it probably was at least a person-year per ton. They probably worked sixty-hour weeks — these people were working long hours.

Seventeenth-century energy externality. England's wood crisis (cannon iron, masts, window glass all charcoal-fueled) drove the founding of Jamestown glassworks and Saugus Ironworks. "The energy crisis of 1973 was not the first energy crisis."

My other example is Saugus Ironworks. Have you been to Saugus Ironworks, in Saugus, Massachusetts, just up the north shore here? Saugus Ironworks was actually another transportation story, but one where it was an energy crisis in the early seventeenth century. Saugus Ironworks was 1619 or so. In the sixteenth and seventeenth century in England they were having an energy crisis. What was the source of energy in England then? Wood. They were deforesting England, and they had three uses of trees — we'll talk about this later. One was to make cast iron for military purposes, to make cannons for your ships. Another was for shipbuilding — you needed the great big masts for the sailing ships. And another — it turns out they were starting to make window glass. I told you the story about bullseye glass, and we'll talk about that some more. They had to use charcoal to make the iron and to make the glass, and then you needed great big trees for the masts of the big sailing ships, man-o'-wars and so on.

First American iron mill (Saugus, MA, 1642–1688). Used bog iron and oyster-shell flux. Eight tons per week. Failed by 1688 from litigation and timber depletion. National Historical Site.

What did they do? Well, someone had discovered North America, so they came over, and the first iron mill was Saugus Ironworks, right up here in Saugus, Massachusetts. It's a national historical site. They have it rebuilt and you can go up there and see the iron master's house, which is a 17th century home. You can see the blast furnace they built, and they basically got the iron ore out of the bogs and neighboring swamps. They used oyster shells for their flux — they needed calcium carbonate. Oyster shells are calcium carbonate. You don't have to dig a mine to get your limestone, just go to the original oysters that created the limestone. They could make eight tons of iron per week up here at Saugus. That started in 1642. It failed by 1688 as a result of litigation, nuisance suits, and the reduction of timber resources. They were tearing down all the trees around here too.

First cast-iron foundry in the United States, with waterwheel-driven bellows reaching the 1150°C needed to melt cast iron. Anchors the productivity-revolution arc that closes the lecture (3,000 person-hours per ton at Saugus vs. 20 minutes today).

If you go to Saugus Ironworks — the Saugus National Historical Site, the first cast iron foundry in the United States — there's a waterwheel, that's the sluice for the waterwheel, and this is the platform they drop the stuff in the top. This is the stone blast chamber. The sluice would run a bellows that blows the blast of air in to get up to the 1,150 degrees you need to melt cast iron. Cast iron was a strategic material militarily, because that's what your cannonballs and your guns and your cannons were made out of. The first cannons were made out of brass, but they weren't as strong, and they were expensive. Eventually people developed cast iron.