Virginia’s soil yielded unexpected resources. Journeyman Blacksmith Shel Browder talks about an early iron foundry at Jamestown.
Lloyd Dobyns: Hi. Welcome to Colonial Williamsburg: Past & Present on history.org. This is â€œBehind the Scenesâ€ where you meet the people who work here. Thatâ€™s my job. Iâ€™m Lloyd Dobyns and mostly I ask questions.
Settlers came to Jamestown in the 1600s looking for natural resources that would make them rich. They were disappointed in their search for gold, but the New World offered a metal nearly as precious: iron. Shel Browder joins me now to tell us more about the early efforts at smelting.
I knew there had been an attempt at an iron foundry at Jamestown, thatâ€™s all I knew. How far did they get, how successful was it?
Shel Browder: Actually, they were successful in what they sought to do. They really were trying to establish a foundry or a furnace there, but to experiment with some of the ores in the area. Thereâ€™s one rather cryptic reference from John Smith in September in 1607, and he says, â€œOne of our best products is little chisels that weâ€™ve made from local iron.â€ So clearly, they are using a very ancient process to smelt iron ore, to make both iron and steel.
Lloyd: Iâ€™d never heard of a search for iron, nor did it occur to me that England would need iron.
Shel: England needs lots of iron. By 1750 â€“ weâ€™ll go back to the production of iron here in the colonies â€“ by 1750, Britainâ€™s North American colonies are producing a lot more iron here than was made in Britain. Itâ€™s needed in Britain for a rather interesting reason. Britainâ€™s iron production was limited by their fuel source.
You need charcoal to make iron with the old methods. Their forests were limited in size. In 1750, British ironworkers â€“ smiths of all sorts working with iron could turn out 45,000 tons of finished iron goods every year. Britain could only produce 16,000 tons of iron every year. Thatâ€™s a huge shortfall.
Lloyd: Well weâ€™ve got a little shortage there.
Shel: But we canâ€™t produce all the iron things that we need, because we donâ€™t have a large, highly-skilled workforce here. So, weâ€™re shipping iron to Britain, and Britain is selling finished iron products back here. Weâ€™re shipping as many tons of iron a year to Britain as we are tons of tobacco from Virginia and Maryland.
Lloyd: Classic colonial relationship.
Shel: Yes, it is.
Lloyd: Ah, smelt. What is smelting?
Shel: Hmm. Itâ€™s obviously related to melting, but youâ€™re not melting the iron. You are reducing the ore. Iron exists in nature as iron oxide. There are only two things that they could really get rid of in the 18th century: they could get rid of the oxygen and some of the mechanical inclusions in the ores. So you need iron ore and charcoal.
The charcoal produces carbon monoxide, which is a reducing agent. The small bloomery furnace â€“ which is what this is, itâ€™s not a blast furnace, but a bloomery furnace â€“ theyâ€™re seldom, theyâ€™re not more than four feet high. You might get as much as a hundred pounds of iron a day. Theyâ€™re fed constantly from the top, with iron ore and charcoal.
Thereâ€™s an air blast from a bellows going into the side. The air blast produces a very intense fire in front of the bellows, but when you get above that in the column of charcoal, youâ€™re producing lots of carbon monoxide, incomplete combustion. The carbon monoxide latches on to the oxygen with the iron oxide, and pulls it right away and leaves iron behind.
Lloyd: Typically then, you would build this furnace near trees, because youâ€™d need trees to make charcoal.
Shel: Correct. The furnace is, if youâ€™re familiar with the chimneas that people put on their patios, itâ€™s basically a smokestack, and inside will be roughly 12 inches to 18 inches in diameter. They need to be somewhere between two and four feet tall. So itâ€™s a long cylindrical column inside, and itâ€™s filled up to the top with charcoal and iron ore, in layers. The air blast comes in from the side, about nine inches or 12 inches from the bottom.
Lloyd: So weâ€™re not talking some huge building here where 100 people are at work. This is a fairly local operation with some workmen, but not a lot.
Shel: You only need a few people. You need somebody to make the charcoal. The iron ore can literally be gathered around here for small sites like this. The furnaces are very simple. Theyâ€™re not made out of fired brick, theyâ€™re made out of topsoil and charcoal in small quantities, and straw and just enough wet yellow clay to bind it together so that it sticks. You build that up in a structure thatâ€™s sometimes referred to as a cob construction: just lumps of clay with all this stuff in it, just wet enough to be a stiff dough.
Lloyd: I ah you mentioned you gather iron ore around here pretty easily. Iâ€™ve never gathered any. What do you look for?
Shel: Iron exists in nature primarily as a red, rusty rock. Itâ€™s a reddish, rusty rock. You can find it laying on the banks of the James and the York Rivers. There are a couple of types of ores you would find around here. One is bog iron, which you literally rake out of bogs, out of the mud in bogs, just as you would gather clams in a mud flat. Itâ€™s kind of wet and a little bit sticky, and it would have to be dried out. If you find the other type of ore, which I guess technically is limonite, it comes from old bogs that have lifted up. There are many of those around the Chesapeake. An earlier term for that is â€œironstone,â€ which is fairly dense and can be even used as stones for foundations.
Lloyd: So after you run this through the heat, and you gather it up, it works like iron? You could, a blacksmith could handle it?
Shel: Weâ€™re not there yet. Weâ€™re not there yet. The next thing that you do is roast it in an open pit. That actually takes some of the oxygen away, but more importantly, it makes it friable, so you can break the ore that you have, which might be in a bigger lump down to something about the size of rock salt. Iâ€™m a southerner, so I would refer to it as the size of grits, or hominy. It turns reddish. It becomes magnetic at that point.
Lloyd: Oh really?
Shel: The charcoal is also crushed, it canâ€™t be big pieces of charcoal, and it canâ€™t be dust either. So charcoal is about the size of a golf ball in modern terms, or a walnut, in older terms. That goes into the top, as I said earlier, in layers. So this column is filled to the top of the little chimney, and itâ€™s never allowed to burn down. You donâ€™t put it in all at once. You fill it up with charcoal until itâ€™s hot, and then you begin layering.
What we found to be best is a pound of ore to a pound of charcoal, weight-wise. The volume is different, of course. And you continue doing that. As it burns down, youâ€™ll add another pound of charcoal and another pound of iron ore. So itâ€™s like constantly building layer cakes that fall out at the bottom. The iron grains, as the oxygen is pulled away and some of the impurities melt, begin to stick together into an object that has long been called a bloom. It has a lot of interstitial spaces in it, so itâ€™s rather porous and open, and itâ€™s not usable directly as it is.
Lloyd: What more do you have to do?
Shel: Well the first thing that we would do, if itâ€™s a 20-pound bloom, is to make it more easily handleable. So we would cut it into four pieces. Then while itâ€™s still hot â€“ itâ€™ll be yellow heat when it comes out â€“ it goes back into the blacksmith shop, it goes right into the forge while itâ€™s still hot, and you begin to pound it into a bar. That forces out some more of the impurities, it begins to align some of the grains of the materials that you cannot get rid of, primarily a silicaceous slag.
Once youâ€™ve drawn it out into a bar by careful hammering, because itâ€™s not very well stuck together, then you cut the bar in two, put it on top of itself, forge-weld it together, draw it back out. You should do that at least four or five times to refine the grain so that you have much finer grain in it. The impurities, the slag, become a fiber when you do this, and they draw out to produce fibers that are actually the length of the bar â€“ rather like the grain in a piece of wood.
Lloyd: So they knew exactly what they had to do, but what evidence have we found that they ever actually got one of these operations going? I mean, John Smith refers to some little chisels, but what else do we know?
Shel: Theyâ€™re actually doing some rather interesting archaeology at Jamestown. It will be next year before we are certain, but they are down into the earliest levels of what was probably a laboratory for doing research, experimenting with all sorts of things that theyâ€™ve found in the oldest part of the oldest layers of the fort.
Some of this is a mystery that wonâ€™t be solved until next year. But theyâ€™ve found, for instance, castings of some of the slag thatâ€™s not included that runs off. Itâ€™s magnetic, and itâ€™s a half of a circle. We see the same thing when we shove an iron poker into the little bloomery furnace to start the stuff moving and to find out whatâ€™s going on. It, in itself, is magnetic, and that seems to happen oddly enough, with no scientific explanation, if you stick the end of that hot iron poker into some water nearby, and you cool the slag thatâ€™s stuck to it very quickly, it freezes the grains in a magnetic alignment.
Lloyd: You say next year youâ€™re going to know more about the thing. What do you think there is to learn?
Shel: I like to describe what we do in the blacksmithâ€™s shop, or in the historic trades, as historical forensics. Weâ€™re looking backwards at processes that were not truly written down. When we make things out of iron in the blacksmithsâ€™s shop, we want to use the older materials. Then we make tools that will go for use by the woodworking trades, for instance, using types of steel and iron that were available in the 18th century.
We do that with our own tools as well. You begin to learn how those tools behaved, and how they held up. Thatâ€™s information that can be communicated to our visitors. So weâ€™re doing two things: weâ€™re educating ourselves, and educating visitors at the same time.