AMERICA 250 • A FIREPLACE, NOT A CONTROL SYSTEM
The Pennsylvania Fireplace
Franklin’s 1744 pamphlet sold an iron insert. He later said 1742. The smoke path misbehaved. None of this is a thermostat
People say Franklin stove and picture a black box in a parlor. What he printed, in Philadelphia in 1744, was An Account of the New Invented Pennsylvanian Fire-Places. It is a sales pamphlet. His friend Robert Grace, who had Warwick Furnace in Chester County, cast the plates and paid to have the pamphlet printed. Franklin’s autobiography, written years later, puts the invention in 1742 and says the household had already been warm “for these four Winters past” when he wrote the account. The editors of his papers notice that those four winters do not land neatly on 1742. Keep both sentences. Do not let a timeline box pick the year the memory forgot.[1]
QUICK ANSWER
What was the Franklin stove?
A cast-iron insert meant to sit in an existing fireplace, warm a stream of incoming air, and send less of the fire straight up the chimney. He called it a Pennsylvania fireplace. Enclosed iron stoves were already in European houses, and German families in Pennsylvania already heated with iron. He did not invent the stove. The thing sold later under his name, with doors and a different flue, is not the 1744 plate.
What will sit still
An open hearth wastes a fire. That was not news
An open fireplace looks generous and heats badly. Most of the heat goes up the flue, and the flue also steals the warm air of the room and pulls cold air in at every crack. People knew this. Iron stoves that boxed the fire were already a trade in Europe, and the five-plate stoves of Pennsylvania German households were already iron boxes in the next room, fed from the kitchen. Franklin was not walking into an empty century with a new idea of “contain the fire.”
What he was selling to an English-style house was an insert: keep the fireplace opening you already have, put iron in it, and try to warm fresh air on the way in instead of only scorching the shins of whoever sits closest. Comfort, less smoke in the room, less wood carried up the stairs. Those are the promises. Wood in a colonial city was cut, hauled, and paid for. A man who sells stoves will say you will burn less of it. The pamphlet’s own title says the advantages are “demonstrated.” In 1744 that word means argued. It does not mean a measured test we can still check.
What the iron was supposed to do
The plates made a firebox in the room. Air from outside, or from a cooler part of the house, was led along the hot iron so it entered the room warmer than it left the outdoors. Smoke was sent through a long path, not straight up, so the metal could take heat before the gases escaped. More hot surface in the room, less of the fire lost at once to the sky. That is the design in his own account.[2] Read the pamphlet when you want his reasons. Do not read a museum label as if it had been in the room.
A brochure, a furnace, and a patent he says he waved off
Grace’s furnace cast the plates. Franklin wrote the pamphlet to make people want them. Agents are named in the record for Boston, Newport, New York, Philadelphia, and Yorktown. This is a small iron business with a famous author, not a lonely experiment that happened to change heating. The autobiography says Governor Thomas liked the description enough to offer a patent for the sole selling of them, and that Franklin declined, because he had enjoyed other men’s inventions and thought he ought to pass this one on. That is his principle, told by him, late. It is also true that he says an ironmonger in London took the pamphlet, changed the machine in ways that hurt it, patented the result, and made some money. Franklin says he did not fight it. He hated disputes, and he says he did not want to live by patents. Believe the offer and the refusal as his account. Do not turn the refusal into proof the stove worked. A man can give away a design that smokes.
He also says, in that same late telling, that the fireplaces were a great saving of wood in many houses. That is a user’s boast from the man who wrote the advertisement. Houses did buy them. Other ironmongers copied them, which is what happens when you refuse a patent and the pamphlet is sitting there. Copies are evidence of a market. They are not a cordwood count.
Less wood is a hope, not a balance sheet
If the insert really kept more of the fire in the room, a household might burn less. If it smoked and they opened a window, or if they ran it badly, they might not. Franklin did not publish a winter’s tally of cords against a neighbor’s open hearth. Modern talk of efficiency, emissions, and lifecycle cost is a different century’s paperwork. The question he could ask was plainer: are the people warm, and is the woodpile going down. His answer was yes. The smoke complaints are why the flue was redesigned. Both can be true. A first design that needs a second man is an ordinary story. Do not promote it into a method called continuous improvement. It is a stove that did not draw, and then a different smoke path.
It is not automation, and it does not grow up into one
There is no sensor, no setpoint, and no actuator. A person lays the fire, sets a damper by hand if there is one, and lives with the draft the chimney gives that day. Iron and a passage are not a controller that notices the room and trims the flame. Closed-loop heat, fans, and thermostats are later machines with their own history. They do not descend from this pamphlet. Saying Franklin “anticipated” building controls because he thought about airflow is how a brochure eats a century. He wanted a warmer room and a smaller woodpile. Stop there.
What not to do with the pamphlet
- Do not say he invented the stove. Iron stoves were already in the colonies and in Europe.
- Do not print 1742 as a settled year. The autobiography says it. The “four winters” in 1744 pull the other way.
- Do not treat the pamphlet’s “demonstrated” as a test. Grace paid for a promotion.
- Do not confuse his plates, Rittenhouse’s flue, and a Victorian stove with his name on the door.
- A refused patent is a choice he reports. It is not proof of performance, and the London copy shows someone else patented a version anyway.
- Nothing here measures the room, adjusts itself, or belongs in a line with a thermostat.
Related pages, which are not sequels
Questions worth a straight answer
Did Benjamin Franklin invent the stove?
No. He designed an iron insert for a fireplace and sold it through Robert Grace’s furnace. Enclosed iron stoves were already a trade.
Was it 1742?
That is the year he gave later, in the autobiography. The 1744 pamphlet says he and his household had been using it for four winters. The editors of the Franklin Papers flag the clash. Use 1744 for the printed account, and do not pretend the first fire has a single settled winter.
Was it more efficient?
He said it saved wood and warmed the room. The smoke path also failed often enough to be redesigned. There is no cordwood ledger in the pamphlet. Treat the savings as his claim.
Is this automation?
No. A person tends the fire. Later thermostats are not this insert with a dial added. The page is here because the series is walking through American machines, and this one is usually oversold.
Primary and Scholarly Sources
- The Papers of Benjamin Franklin, digital edition, Yale University and the American Philosophical Society, also on Founders Online: the headnote to An Account of the New Invented Pennsylvanian Fire-Places (Philadelphia, 1744). Grace, Warwick Furnace, the pamphlet as a promotion he paid for, Governor Thomas’s patent offer, and the editors’ warning that 1742 from the autobiography sits badly against “four Winters past.” The 1744 account and headnote. The older portal is franklinpapers.org.
- Benjamin Franklin, An Account of the New Invented Pennsylvanian Fire-Places (Philadelphia: printed and sold by B. Franklin, 1744). His description of the plates and the draft. The title’s promise that every objection has been answered is the salesman talking. Read it as that.
- Benjamin Franklin, Autobiography, the passage on the open stove, Robert Grace, the refused patent, the London ironmonger, and the claim of a great saving of wood. Late, and in his favor. Use it for what he wanted remembered, then check it against the 1744 headnote.
- Library of Congress, “Benjamin Franklin: Scientist and Inventor” and the Benjamin Franklin Papers. Useful for the manuscripts and the exhibit frame. An exhibit is not a test of the flue.
- The Franklin Institute. A museum’s overview of the man. Where it smooths the fireplace into a step toward modern heating controls, come back to the pamphlet.
The book offered below is a separate product. It is not a source for the dates or the flue.