Vast majority of manual labour in iron and bronze ages?

[Accelerator]

So plot point: Some made genius creates a primitive stirling engine in a sword and sorceryverse, kicking off the study of thermodynamics, pressure, mechanical clockwork, and metallurgy several centuries earlier than before.

It's a primitive engine, but it *works*. Now I won't go into details but it's really primitive. Good enough to do useful work, better than the Aeoliphile. Not remotely as good as a steam engine, and probably explodes once or twice due to lacking metallurgy. But it works.

Let's say that it was invented in the aftermath of a deadly plague and drought that left an entire area reeling. Efforts were made in order to bypass the sudden loss of labour and to make an irrigation system. Archimedes screw, pulleys, wind-powered mills and pumps... all were used. Then divine intervention/ flash of genius occurred. And the stirling engine was first made. First as a toy. Then as a tool.

So now... something useful. What would be the most common usage of this? Keep in mind this is sword and sorcery, bronze/ iron age.

[brian 333]

Pumping water out of mines.

[Laserlight]

In mills of various sorts, I would think. First off would be grinding grain, because you need that everywhere and you don't always have suitable waterflow or wind. But you'd also have fulling, trip hammers and hammermills, drawing wire, sawmills, and so forth. Pumps for irrigation and getting water out of mines. Stationary engines for hauling loads up short steep inclines. Sidewheeler riverboats.

[brian 333]

In mills of various sorts, I would think. First off would be grinding grain, because you need that everywhere and you don't always have suitable waterflow or wind. But you'd also have fulling, trip hammers and hammermills, drawing wire, sawmills, and so forth. Pumps for irrigation and getting water out of mines. Stationary engines for hauling loads up short steep inclines. Sidewheeler riverboats.

You have to keep in mind that even with a century of research behind them, our Stirling engines are slow and weak. This is because the heat/cool cycle which powers them requires time for the heat to dissipate, and systems which speed up the cooling cycle also consume power that could otherwise be used for the intended work.

A water pump has a natural heat sink, the water that is being pumped, and the heated water will be expelled anyway. Plus, there will be no need for power consuming gearing and linkages to transfer linear thrust to rotary power.

A Stirling engine attached to a water pump draws water into the pump, then uses the ejected water to cool the engine for the next intake cycle. It is a slow but steady process. Absent a natural heat sink, Stirling engines have proven to be inferior to manual labor for almost every purpose. The reason we don't use Stirling engines today is that they simply lack the horsepower.

One could envision a salamander and a sprite alternately heating and cooling the engine, I suppose, but at that point, it is probably more efficient to make them just do the work.

[Martin Greywolf]

At first, I thought it was about someone somehow pulling off low level steam power in bronze age, probably via a magical metal and got excited. Then I realized it's a Stirling engine.

They are useless. In bronze age setting, they are absolutely useless.

Basically, there is no use for them that you'd not be better served by deploying a donkey - a cheaper, easy to make easy to maintain donkey, with better fuel efficiency. Those stories about Stirling engine cars use some sort of a modified engine.

Just about the only place you could use this in is in ships, you can put the radiators in the water to get more efficiency and size is less of an issue - problem is, that is the case with modern ships. With bronze age, we're talking about someone figuring out an entirely new naval movement paradigm, going from sails to... maybe paddlewheels? Sure, it could happen, but it will take a lot of time and experimentation, and that is expensive with ships, so only major nations can afford them. Maybe something like ancient Egypt analog? Then and again, it's after a plague, so everyone will be more careful in where they put their money, so...

(okay, there were a few paddleboats around in places, but they were kinda rare, so unless your setting specifically used those already, my point stands)

[Tvtyrant]

My first thought is canals and aqueducts. Pumping water over mts, filling canals for ships, all things done that required huge and wasteful manpower.

Second would be ferries, same basic idea but pulling a rope to move a ship back and forth.

Third I would think rock crushing. Grinding rocks for ore is a sound application, although what the crusher is made of I have no idea.

[sktarq]

First thing is to look at what people used water powered mechanical energy for in that era.

Cutting Stone/Wood (yup water powered marble cutters were a thing even way back)
Milling of grain
Grinding wood fragments to pulp (for papermaking)
Hammering Iron
Ore crushing
post Rett crushing of hemp

So water pumps/screws. For both getting water where you want it (agriculture and setting up supplies in a water tower/aqueduct for a town) and moving water away from where you don't want it (mines/quarries, (well some of the processing parts like lots of water but usually not at the ore bed in this era) and agriculture/urban development of drained lowlands). Things like the Noria existed and could be replicated by this stirling engine in places where water power is unavailable.

[Tvtyrant]

Wood pulping is a good one ^
Affordable paper revolution seems like a realistic use.

[brian 333]

Those things are fine for almost any engine except a Stirling engine, which is what the OP specified. A Stirling engine is reliant on a heat sink or it will run mere minutes before heat saturation renders it inoperable, and once it has heated its heat sink it stops working anyway.

If the OP wishes to open up other engine types, a perusal of the uses to which Hero of Alexandria put simple steam engines would be enlightening.

Keep in mind that until the (water-powered) industrial revolution, manufacture of reliable engines was not possible. The reason has nothing to do with technological knowledge. We have adapted, but every tool we know today was known to Hero in year 1. BC and AD.

What it has to do with is reliable manufacture of parts which meet mechanical specifications. To see this in action, watch an episode of Forged In Fire. Master metalsmiths turn out crap blades in every show. Blades which any foundry could churn out by the hundreds with no flaws in the same time span.

Now I could envision a priesthood utilizing church secrets to manufacture simple engines which are then tended by acolytes who insure the proper rites and sacrifices are observed.

The huge church belches smoke and fire all day and night while magical wagons with mysterious loads flow in and out with almost as much noise as the factory.

[Accelerator]

Those things are fine for almost any engine except a Stirling engine, which is what the OP specified. A Stirling engine is reliant on a heat sink or it will run mere minutes before heat saturation renders it inoperable, and once it has heated its heat sink it stops working anyway.

If the OP wishes to open up other engine types, a perusal of the uses to which Hero of Alexandria put simple steam engines would be enlightening.

Keep in mind that until the (water-powered) industrial revolution, manufacture of reliable engines was not possible. The reason has nothing to do with technological knowledge. We have adapted, but every tool we know today was known to Hero in year 1. BC and AD.

...

Can you tell me what Hero of Alexandria did with simple steam engines? He created the aleophile. He created simple steam mechanisms to open temple doors. He made toys. He made gizmos and showbiz. Nice looking mechanisms, yes, but the aleophile was far, far from any attempt to create a working steam engine.

And why *wouldn't* it have a heat sink?

[brian 333]

...

Can you tell me what Hero of Alexandria did with simple steam engines? He created the aleophile. He created simple steam mechanisms to open temple doors. He made toys. He made gizmos and showbiz. Nice looking mechanisms, yes, but the aleophile was far, far from any attempt to create a working steam engine.

And why *wouldn't* it have a heat sink?

The difference between a toy and a tool is scale. The pistons and linkages that opened temple doors and the ones that move trains are nearly identical, except that the train ones are bigger and have more exact tolerances. A Stirling engine requires much higher tolerances or else too much energy is lost to friction or is wasted through leaks, neither of which is all that important when all you want is something to open a door.

Hero's gimmicks were all one-off wonders because there was no industrial infrastructure to take advantage of his creations and market them. But it is clear that he understood gearing and drive trains well enough to make use of a large scale steam engine if he had the industrial capacity to scale up his toy steam jet engine, (which is an order of magnitude more powerful than a Stirling engine of similar mass and far easier to build.)

As for heat sinks: they only work until they reach their saturation point, getting less efficient as they absorb heat. The Stirling engine relies upon heating, cooling, heating, cooling, heating, cooling, and so on. Heating is easy. Cooling is not. The heat needs somewhere to go, and it can only get there as fast as the transfer medium will allow. Of the three available methods, conduction is fastest, so having a large body of heat-conducting material, a heat sink, physically contacting the engine, is the fastest way to cool the engine. Now you need to keep the heat sink cool or it rapidly becomes less efficient, and the Stirling engine becomes less efficient as a result.

In almost every case manual labor beats the cost of operating a Stirling engine for the same work, and manual labor does not require a skilled machinist to maintain it. We've known about them for over a century now and even with our technical and industrial know how we have yet to develop them beyond the 'science experiment' stage. And scaling them up to useful size only adds to the heat sink problem.

[Martin Greywolf]

The difference between a toy and a tool is scale.

Yeah, and in Hero's case, he couldn't upscale the pressure and couldn't upscale the size. Metallurgy wasn't there for pressure and size is both difficult to do and more prone to those metallurguc errors that could get you a steam pipebomb instead of a boiler. You can't have industrial revolution on this level of metallurgical understanding.

Stirling engines are still useless in pre-modern era.

[brian 333]

Our own early steam era was full of boiler explosions. Yeah, scaling up is hard.

[Lvl 2 Expert]

Regardless, I feel like a concept like this could lead to an interesting world.

One of the key components to the success of many middle and late bronze age empires (and quite a few places in classical antiquity too) seems to have been a strong top-down organization. There were government officials who did things like telling the farmers when to plant their crops. One of the reasons for this specifically in the bronze age is the limitations on a clay tablet based writing system. Try writing a half decent 50 page manual on that stuff, it'll be massive. Plus most people are illiterate anyway. You can't arm everyone with all the knowledge they need that way, so instead you store the knowledge in a central location, and distribute it as needed. This is most likely where the concept of the ten commandments comes from. These states typically had hundreds of laws (half of which directly or indirectly about farming), but you can't ask people to memorize all of that. So instead govermnent officials would educate people (after a fashion) using clay tablets (stone tables, after you bake them) with just the highlights, like "don't murder" and "don't steal". (We don't expect people to know all the details either, but a rule like "don't use your phone while driving, except when it's on a standard or you're using it hands free" probably wouldn't have made the shortlist.)

This is radically different from the way Europe from the early modern era on has been organized. Our current era if anything is build much more bottom up. One of the earlier examles is the concept of farmer's almanacs, that appeared somewhere before the printing press (late middle ages, possibly earlier?). They were books with lots of pictures that explained things like how to determine when to plant crops. They would often be publically available for reading/viewing in churches. It's basically teaching a man to fish so you won't have to tell him when exactly to pull up his fishing rod for the rest of his life. We still do this today, with a strong emphasis on education throughout at least the Western world. I would argue it's this approach to knowledge that also led to things like the enlightenment and modern democracies. Same principle, except with a different form of power. It would be a long road, full of nobles who treat anyone lesser than them as stupid, but by the time steam engines roll around there are definitely elements like a strong non-noble merchant class, private enterprise and independent inventors with the knowledge and connections/accces to a free market to set up proper development and producton processes.

It would honestly be kind of fascinating to see how the same developments might go in a highly centralized society like a late bronze age state. Can such a state handle the complexity needed for a proper industrial revolution? Does their state structure survive the transition? What happens to say the attitutes towards slavery? Is there going to be an entirely separate class of engineers just below the clerks that run the kingdom's administration? Set the scenario a bit before the bronze age collapse, when these states are at their height of power, or a semi-equivalent time in your swords and sorcery universe, and I think you have some pretty cool alternate history.

Maybe not 100% realistic, but pretty cool.

Maybe patch the mettalurgic and technical problems with something like ritual elemental magic?

[Accelerator]

Regardless, I feel like a concept like this could lead to an interesting world.

One of the key components to the success of many middle and late bronze age empires (and quite a few places in classical antiquity too) seems to have been a strong top-down organization. There were government officials who did things like telling the farmers when to plant their crops. One of the reasons for this specifically in the bronze age is the limitations on a clay tablet based writing system. Try writing a half decent 50 page manual on that stuff, it'll be massive. Plus most people are illiterate anyway. You can't arm everyone with all the knowledge they need that way, so instead you store the knowledge in a central location, and distribute it as needed. This is most likely where the concept of the ten commandments comes from. These states typically had hundreds of laws (half of which directly or indirectly about farming), but you can't ask people to memorize all of that. So instead govermnent officials would educate people (after a fashion) using clay tablets (stone tables, after you bake them) with just the highlights, like "don't murder" and "don't steal". (We don't expect people to know all the details either, but a rule like "don't use your phone while driving, except when it's on a standard or you're using it hands free" probably wouldn't have made the shortlist.)

This is radically different from the way Europe from the early modern era on has been organized. Our current era if anything is build much more bottom up. One of the earlier examles is the concept of farmer's almanacs, that appeared somewhere before the printing press (late middle ages, possibly earlier?). They were books with lots of pictures that explained things like how to determine when to plant crops. They would often be publically available for reading/viewing in churches. It's basically teaching a man to fish so you won't have to tell him when exactly to pull up his fishing rod for the rest of his life. We still do this today, with a strong emphasis on education throughout at least the Western world. I would argue it's this approach to knowledge that also led to things like the enlightenment and modern democracies. Same principle, except with a different form of power. It would be a long road, full of nobles who treat anyone lesser than them as stupid, but by the time steam engines roll around there are definitely elements like a strong non-noble merchant class, private enterprise and independent inventors with the knowledge and connections/accces to a free market to set up proper development and producton processes.

It would honestly be kind of fascinating to see how the same developments might go in a highly centralized society like a late bronze age state. Can such a state handle the complexity needed for a proper industrial revolution? Does their state structure survive the transition? What happens to say the attitutes towards slavery? Is there going to be an entirely separate class of engineers just below the clerks that run the kingdom's administration? Set the scenario a bit before the bronze age collapse, when these states are at their height of power, or a semi-equivalent time in your swords and sorcery universe, and I think you have some pretty cool alternate history.

Maybe not 100% realistic, but pretty cool.

Maybe patch the mettalurgic and technical problems with something like ritual elemental magic?

There's no reason why someone can't make early lathes powered by foot pedals. Lathes are pretty old tech, and can be improved pretty easily. Metallurgical problems can be solved by the bog-standard fantasy world's weirdly durable metals and ****.

Some of the problems can be solved by having things like a rubber or plastic analogue being invented by alchemists that are derived from tree sap or the like, meaning that you don't need that level of technical precision, just good enough stuff.

Though that statement on the history, farmers almanacs and centralized bureaucracy is interesting. Where'd you hear it from?

[Lvl 2 Expert]

Though that statement on the history, farmers almanacs and centralized bureaucracy is interesting. Where'd you hear it from?

Not from one easily referable place I still remember I'm afraid. Both the early modern era (mostly centered around my own Netherlands) and the bronze age (in particular the Hittites, because it seemed like a weird enough pick to be something I'd like) are favorites of mine, so comparing and contrasting eventually came up.

One of the sources I can still retrace is the Extra History series on the bronze age collapse. I don't remember which information I got from there, but it must have been interesting, because their video's in general are. I think they had stuff in there about the strong hierarchical organization of the empires. Another one I know I've watched attentively is The Hittites, a 2003 documentary. I know that's where I heard that these guys' cities already had water and plumbing systems (of a sort).

I could have sworn I had a good Wikipedia page on the Farmer's almanac, I can't seem to retrace it though. I know I stumbled upon that example more or less accidentally, just researching where that concept came from. I can find one example that contains pictures of what you should be doing in roughly each month and how many hours of light you have to do it. Now that I type that out it actually sounds closer to "tell farmers when to plant" than my argument is entirely happy with. But at least then we start getting to the printing press, the establishment of universities (for the rich mostly at the beginning, but it's a step up from only a handful getting to learn at a king's court) and a general trend towards a kind of democratization of knowledge.

(I also put something between brackets about about half of the bronze age laws being about agriculture, I think I got that from a video. But it seems to be an exaggeration.)

I'm also pretty sure I'm oversimplifying. Way, waaaay oversimplifying. But this is a forum post, you were expecting that.

[Accelerator]

Not from one easily referable place I still remember I'm afraid. Both the early modern era (mostly centered around my own Netherlands) and the bronze age (in particular the Hittites, because it seemed like a weird enough pick to be something I'd like) are favorites of mine, so comparing and contrasting eventually came up.

One of the sources I can still retrace is the Extra History series on the bronze age collapse. I don't remember which information I got from there, but it must have been interesting, because their video's in general are. I think they had stuff in there about the strong hierarchical organization of the empires. Another one I know I've watched attentively is The Hittites, a 2003 documentary. I know that's where I heard that these guys' cities already had water and plumbing systems (of a sort).

I could have sworn I had a good Wikipedia page on the Farmer's almanac, I can't seem to retrace it though. I know I stumbled upon that example more or less accidentally, just researching where that concept came from. I can find one example that contains pictures of what you should be doing in roughly each month and how many hours of light you have to do it. Now that I type that out it actually sounds closer to "tell farmers when to plant" than my argument is entirely happy with. But at least then we start getting to the printing press, the establishment of universities (for the rich mostly at the beginning, but it's a step up from only a handful getting to learn at a king's court) and a general trend towards a kind of democratization of knowledge.

(I also put something between brackets about about half of the bronze age laws being about agriculture, I think I got that from a video. But it seems to be an exaggeration.)

I'm also pretty sure I'm oversimplifying. Way, waaaay oversimplifying. But this is a forum post, you were expecting that.

You know, I'm wondering.

Like, the bronze age collapse was a ****ing long time ago. Like, really long time, and fell to pieces in a terrible way. That vellum in the medieval age was created less than a few hundred years ago, probably kept in some monastery, and also probably wasn't there in some kind of horrific disaster.

I say that there is a distinct chance that vellum books and parchments and clay tablets were *also* present during the bronze age, but due to the increase in time as well as horrible chaos, such evidence of things were lost far more easily. It's not like there isn't a huge difference in time and circumstances, and it's not like places like Sumer or Mesopotamia didn't have pictographic symbols to help tell farmers and clerks what to do.

[brian 333]

I had previously suggested a priesthood devoted to technology. Guilds and arcanists also come to mind. Technological innovation does not have to come about in fantasy exactly as it did for us. Simple engines were known long before they were practical, so if some wizard created a magical means to purify metal and produce alloys of consistent quality the techno-magical industrial revolution can begin.

I agree it is fun to mix tech and magic in a campaign

[Accelerator]

I had previously suggested a priesthood devoted to technology. Guilds and arcanists also come to mind. Technological innovation does not have to come about in fantasy exactly as it did for us. Simple engines were known long before they were practical, so if some wizard created a magical means to purify metal and produce alloys of consistent quality the techno-magical industrial revolution can begin.

I agree it is fun to mix tech and magic in a campaign

You mean to say like the Adeptus Mechanicus? In that case, what would it be like? It would probably have a high importance placed on skill and knowledge. Likely considering those who made great advances or insights to be blessed by the gods, like how a man can be given great insights by a religious vision, that moments of genius are considered to be the equivalent of messages from on high. And like how a man can be considered to be blessed by wandering over a pot of gold, a man can be blessed by making a great discovery by accident.

Probably focused on reading, writing as well, because information technology. Printing? A love for tools? A prometheus-esque god that gave all men insight, thought, and tools, when all others in Creation had claws, massive muscles, armoured shells, or other unnatural abilities like those in fiends and elementals (Sword and sorcery verse).

Probably considers transmission of technology and technique to be part of their life goals, instead of simply hoarding it all. Mysteries are first given to the priests (by divine insight) and then disseminated slowly to those beneath them. Multiple claves and schisms, based upon multiple different methods of obtaining the same result. Some may create coral-esque creatures to create vast buildings. Others go to steampunk.

[brian 333]

The great mages don't all create academies of arcana. Some hoard their knowledge.

So too with technologists. There may be some who hoard 'trade secrets' and protect their 'patents', but some may choose to be teachers as well as tinkers. Such a man was Professor Henry, the first director of the Smithsonian, who invented the current transformer, electric motor, and the telegraph, and significantly improved the power of electromagnets. Other guys patented his inventions because he would not. But we would not know Faraday, Moorse, Edison, or Tesia without him.

Opposite Henry were Westinghouse and Edison who patented everything whether they invented it or not, then jealously guarded those patents.

There is no reason a fantasy world could not have its equivalent of Current Wars, complete with electric elementals.

[Yakk]

So plot point: Some made genius creates a primitive stirling engine in a sword and sorceryverse, kicking off the study of thermodynamics, pressure, mechanical clockwork, and metallurgy several centuries earlier than before.

It's a primitive engine, but it *works*. Now I won't go into details but it's really primitive. Good enough to do useful work, better than the Aeoliphile. Not remotely as good as a steam engine, and probably explodes once or twice due to lacking metallurgy. But it works.

Let's say that it was invented in the aftermath of a deadly plague and drought that left an entire area reeling. Efforts were made in order to bypass the sudden loss of labour and to make an irrigation system. Archimedes screw, pulleys, wind-powered mills and pumps... all were used. Then divine intervention/ flash of genius occurred. And the stirling engine was first made. First as a toy. Then as a tool.

So now... something useful. What would be the most common usage of this? Keep in mind this is sword and sorcery, bronze/ iron age.

As others have noted, making something - even a Stirling engine - is far easier than making it good.

So what you need are feedback loops. The first thing you need is for it to be good enough to invest a large amount of resources into making more of them. Because once you make a large number of something, you start getting better at making it. Not only because you practice making it, but because some minor improvement that boosts performance by 1% goes from being a waste of time to a huge source of additional profits.

I mean, you can either use crappy metal, or spend a large amount of time figuring out why some metal is a bit better than others. The first, well, half of your pumps explode when tested. The other? After a month of work, you get the rate of exploding pumps down to 40%.

If you are making 1 working pump a month, that means you go from 24 pumps a year to 20 pumps a year. 4 pumps a year work saved. How hard was finding the better metal again?

If you are making 100 working pumps a month, that means you go from 2400 pumps a year to 2000 pumps a year to get that many working. 400 pumps a year saved. That better metal is worth a lot of pumps!

---

Stirling engines need a heat sink, which means they are only usable if you are pumping water.

Pumping water out of coal mines is a great use of them, because by doing so you make coal cheaper. Which makes the heating part of the stirling engine cheaper.

If there is already moving water, a stirling engine is probably useless; a waterwheel is going to be a better plan. A stirling engine turns non-edible coal + still water into work.

Irrigation has a problem; you usually use it in already fertile areas where you need to make more land produce food. Which isn't something you run into during a labor shortage.

A combined doubt and a plague, maybe? That might do it; a need to irrigate and a loss of labor to do it.

You could also throw in a population migration; some people move into an area where there isn't enough water, but they do have knowledge of how irrigation worked elsewhere. Then the area is depopulated, and they need to keep the irrigation systems running.

There is a coal seam right next to the spot where they pump water up to the reservoir from which they feed their irrigation system. They start using the stirling engine there, and don't have to move the coal far. Then they run into water table issues in the coal mine, and pump water out of the coal mine using a stirling engine (and maybe cable-carts of coal as well?)

You build wooden rail roads for the coal carts out of the mines. And you then start exporting the excess coal down to the city, where it is used for heating ... and pumping water using more engines.

That gives you time to iterate and improve the stirling engine. Then you export this elsewhere, doing similar things. A mining engineer builds a bilge pump for their ships, pumping water out into the ocean, using the stirling engine. This starts as a toy; later experiments try using it to run ores, which turn into water wheels. Now you have coal-powered Stirling Engine tugs in the harbor (it only works where coal is cheap).

The area becomes wealthier as the population grows and the irrigation systems reliably work. Metals are found, and the coal-powered stirling engine pumps let the mines go deeper. Slaves are used up in the mines instead of laboring in the fields or pushing their galleys (now water-wheel powered). A war with a nearby empire happens, the locals manage to fight well enough that either they win, or the empire starts looking into their strange technology.