Future past: steam

Let’s talk about steam. I don’t mean the malware installed on most gamers’ computers, but the real thing: hot, evaporated water. You may see it as just something given off by boiling stew or dying cars, but it’s so much more than that. For steam was the fluid that carried us into the Industrial Revolution.

And whenever we talk of the Industrial Revolution, it’s only natural to think about its timing. Did steam power really have to wait until the 18th century? Is there a way to push back its development by a hundred, or even a thousand, years? We can’t know for sure, but maybe we can make an educated guess or two.

Intro

Obviously, knowledge of steam itself dates back to the first time anybody ever cooked a pot of stew or boiled their day’s catch. Probably earlier than that, if you consider natural hot springs. However you take it, they didn’t have to wait around for a Renaissance and an Enlightenment. Steam itself is embarrassingly easy to make.

Steam is a gas; it’s the gaseous form of water, in the same way that ice is its solid form. Now, ice forms naturally if the temperature gets below 0°C (32°F), so quite a lot of places on Earth can find some way of getting to it. Steam, on the other hand requires us to take water to its boiling point of 100°C (212°F) at sea level, slightly lower at altitude. Even the hottest parts of the world never get temperatures that high, so steam is, with a few exceptions like that hot spring I mentioned, purely artificial.

Cooking is the main way we come into contact with steam, now and in ages past. Modern times have added others, like radiators, but the general principle holds: steam is what we get when we boil water. Liquid turns to gas, and that’s where the fun begins.

Theory

The ideal gas law tells us how an ideal gas behaves. Now, that’s not entirely appropriate for gases in the real world, but it’s a good enough approximation most of the time. In algebraic form, it’s PV = nRT, and it’s the key to seeing why steam is so useful, so world-changing. Ignore R, because it’s a constant that doesn’t concern us here; the other four variables are where we get our interesting effects. In order: P is the pressure of a gas, V is its volume, n is how much of it there is (in moles), and T is its temperature.

You don’t need to know how to measure moles to see what happens. When we turn water into steam, we do so by raising its temperature. By the ideal gas law, increasing T must be balanced out by a proportional increase on the other side of the equation. We’ve got two choices there, and you’ve no doubt seen them both in action.

First, gases have a natural tendency to expand to fill their containers. That’s why smoke dissipates outdoors, and it’s why that steam rising from the pot gets everywhere. Thus, increasing V is the first choice in reaction to higher temperatures. But what if that’s not possible? What if the gas is trapped inside a solid vessel, one that won’t let it expand? Then it’s the backup option: pressure.

A trapped gas that is heated increases in pressure, and that is the power of steam. Think of a pressure cooker or a kettle, either of them placed on a hot stove. With nowhere to go, the steam builds and builds, until it finds relief one way or another. (With some gases, this can come in the more dramatic form of a rupture, but household appliances rarely get that far.)

As pressure is force per unit of area, and there’s not a lot of area in the spout of a teapot, the rising temperatures can cause a lot of force. Enough to scald, enough to push. Enough to…move?

Practice

That is the basis for steam power and, by extension, many of the methods of power generation we still use today. A lot of steam funneled through a small area produces a great amount of force. That force is then able to run a pump, a turbine, or whatever is needed, from boats to trains. (And even cars: some of the first automobiles were steam-powered.)

Steam made the Industrial Revolution possible. It made most of what came after possible, as well. And it gave birth to the retro fad of steampunk, because many people find the elaborate contraptions needed to haul superheated water vapor around to be aesthetically pleasing. Yet there is a problem. We’ve found steam-powered automata (e.g., toys, “magic” temple doors) from the Roman era, so what happened? Why did we need over 1,500 years to get from bot to Watt?

Unlike electricity, where there’s no obvious technological roadblock standing between Antiquity and advancement, steam power might legitimately be beyond classical civilizations. Generation of steam is easy—as I’ve said, that was done with the first cooking pot at the latest. And you don’t need an ideal gas law to observe the steam in your teapot shooting a cork out of the spout. From there, it’s not too far a leap to see how else that rather violent power can be utilized.

No, generating small amounts of steam is easy, and it’s clear that the Romans (and probably the Greeks, Chinese, and others) could do it. They could even use it, as the toys and temples show. So why didn’t they take that next giant leap?

The answer here may be a combination of factors. First is fuel. Large steam installations require metaphorical and literal tons of fuel. The Victorian era thrived on coal, as we know, but coal is a comparatively recent discovery. The Romans didn’t have it available. They could get by with charcoal, but you need a lot of that, and they had much better uses for it. It wouldn’t do to cut down a few acres of forest just to run a chariot down to Ravenna, even for an emperor. Nowadays, we can make steam by many different methods, including renewable variations like solar boilers, but that wasn’t an option back then. Without a massive fuel source, steam—pardon the pun—couldn’t get off the ground.

Second, and equally important, is the quality of the materials that were available. A boiler, in addition to eating fuel at a frantic pace, also has some pretty exacting specifications. It has to be built strong enough to withstand the intense pressures that steam can create (remember our ideal gas law); ruptures were a deadly fixture of the 19th century, and that was with steel. Imagine trying to do it all with brass, bronze, and iron! On top of that, all your valves, tubes, and other machinery must be built to the same high standard. It’s not just a gas leaking out, but efficiency.

The ancients couldn’t pull that off. Not from lacking of trying, mind you, but they weren’t really equipped for the rigors of steam power. Steel was unknown, except in a few special cases. Rubber was an ocean away, on a continent they didn’t know existed. Welding (a requirement for sealing two metal pipes together so air can’t escape) probably wasn’t happening.

Thus, steam power may be too far into the future to plausibly fit into a distant “retro-tech” setting. It really needs improvements in a lot of different areas. That’s not to say that steam itself can’t fit—we know it can—but you’re not getting Roman railroads. On a small scale, using steam is entirely possible, but you can’t build a classical civilization around it. Probably not even a medieval one, at that.

No, it seems that steam as a major power source must wait until the rest of technology catches up. You need a fuel source, whether coal or something else. You absolutely must have ways of creating airtight seals. And you’ll need a way to create strong pressure vessels, which implies some more advanced metallurgy. On the other hand, the science isn’t entirely necessary; if your people don’t know the ideal gas law yet, they’ll probably figure it out pretty soon after the first steam engine starts up. And as for finding uses, well, they’d get to that part without much help, because that’s just what we do.

Future past: Electricity

Electricity is vital to our modern world. Without it, I couldn’t write this post, and you couldn’t read it. That alone should show you just how important it is, but if not, then how about anything from this list: air conditioning, TVs, computers, phones, music players. And that’s just what I can see in the room around me! So electricity seems like a good start for this series. It’s something we can’t live without, but its discovery was relatively recent, as eras go.

Intro

The knowledge of electricity, in some form, goes back thousands of years. The phenomenon itself, of course, began in the first second of the universe, but humans didn’t really get to looking into it until they started looking into just about everything else.

First came static electricity. That’s the kind we’re most familiar with, at least when it comes to directly feeling it. It gives you a shock in the wintertime, it makes your clothes stick together when you pull them out of the drier, and it’s what causes lightning. At its source, static electricity is nothing more than an imbalance of electrons righting itself. Sometimes, that’s visible, whether as a spark or a bolt, and it certainly doesn’t take modern convenience to produce such a thing.

The root electro-, source of electricity and probably a thousand derivatives, originally comes from Greek. There, it referred to amber, that familiar resin that occasionally has bugs embedded in it. Besides that curious property, amber also has a knack for picking up a static charge, much like wool and rubber. It doesn’t take Ben Franklin to figure that much out.

Static electricity, however, is one-and-done. Once the charge imbalance is fixed, it’s over. That can’t really power a modern machine, much less an era, so the other half of the equation is electric current. That’s the kind that runs the world today, and it’s where we have volts and ohms and all those other terms. It’s what runs through the wires in your house, your computer, your everything.

Theory

The study of current, unlike static electricity, came about comparatively late (or maybe it didn’t; see below). It wasn’t until the 18th century that it really got going, and most of the biggest discoveries had to wait until the 19th. The voltaic pile—which later evolved into the battery—electric generators, and so many more pieces that make up the whole of this electronic age, all of them were invented within the last 250 years. But did they have to be? We’ll see in a moment, but let’s take a look at the real world first.

Although static electricity is indeed interesting, and not just for demonstrations, current makes electricity useful, and there are two ways to get it: make it yourself, or extract it from existing materials. The latter is far easier, as you might expect. Most metals are good conductors of electricity, and there are a number of chemical reactions which can cause a bit of voltage. That’s the essence of the battery: two different metals, immersed in an acidic solution, will react in different ways, creating a potential. Volta figured this much out, so we measure the potential in volts. (Ohm worked out how voltage and current are related by resistance, so resistance is measured in ohms. And so on, through essentially every scientist of that age.)

Using wires, we can even take this cell and connect it to another, increasing the amount of voltage and power available at any one time. Making the cells themselves larger (greater cross-section, more solution) creates a greater reserve of electricity. Put the two together, and you’ve got a way to store as much as you want, then extract it however you need.

But batteries eventually run dry. What the modern age needed was a generator. To make that, you need to understand that electricity is but one part of a greater force: electromagnetism. The other half, as you might expect, is magnetism, and that’s the key to generating power. Moving magnetic fields generate electrical potential, i.e., current. And one of the easiest ways to do it is by rotating a magnet inside another. (As an experiment, I’ve seen this done with one of those hand-cranked pencil sharpeners, so it can’t be that hard to construct.)

One problem is that the electricity this sort of generator makes isn’t constant. Its potential, assuming you’ve got a circular setup, follows a sine-wave pattern from positive to negative. (Because you can have negative volts, remember.) That’s alternating current, or AC, while batteries give you direct current, DC. The difference between the two can be very important, and it was at the heart of one of science’s greatest feuds—Edison and Tesla—but it doesn’t mean too much for our purposes here. Both are electric.

Practice

What does it take to create electricity? Is there anything special about it that had to wait until 1800 or so?

As a matter of fact, not only was it possible to have something electrical before the Enlightenment, but it may have been done…depending on who you ask. The Baghdad battery is one of those curious artifacts that has multiple plausible explanations. Either it’s a common container for wine, vinegar, or something of that sort, or it’s a 2000-year-old voltaic cell. The simple fact that this second hypothesis isn’t immediately discarded answers one question: no, nothing about electricity requires advanced technology.

Building a rudimentary battery is so easy that it almost has to have been done before. Two coins (of different metals) stuck into a lemon can give you enough voltage to feel, especially if you touch the wires to your tongue, like some people do with a 9-volt. Potatoes work almost as well, but any fruit or vegetable whose interior is acidic can provide the necessary solution for the electrochemical reactions to take place. From there, it’s not too big a step to a small jar of vinegar. Metals known in ancient times can get you a volt or two from a single cell, and connecting them in series nets you even larger potentials. It won’t be pretty, but there’s absolutely nothing insurmountable about making a battery using only technology known to the Romans, Greeks, or even Egyptians.

Generators a bit harder. First off, you need magnets. Lodestones work; they’re naturally magnetized, possibly by lightning, and their curious properties were first noticed as early as 2500 years ago. But they’re rare and hard to work with, as well as probably being full of impurities. Still, it doesn’t take a genius (or an advanced civilization) to figure out that these can be used to turn other pieces of metal (specifically iron) into magnets of their own.

Really, then, creation of magnets needs iron working, so generators are beyond the Bronze Age by definition. But they aren’t beyond the Iron Age, so Roman-era AC power isn’t impossible. They may not understand how it works, but they have the means to make it. The pieces are there.

The hardest part after that would be wire, because shuffling current around needs that. Copper is a nice balance of cost and conductivity, which is why we use it so much today; gold is far more ductile, while silver offers better conduction properties, but both are too expensive to use for much even today. The latter two, however, have been seen in wire form since ancient times, which means that ages past knew the methods. (Drawn wire didn’t come about until the Middle Ages, but it’s not the only way to do it.) So, assuming that our distant ancestors could figure out why they needed copper wire, they could probably come up with a way to produce it. It might not have rubber or plastic insulation, but they’d find something.

In conclusion, then, even if the Baghdad battery is nothing but a jar with some leftover vinegar inside, that doesn’t mean electricity couldn’t be used by ancient peoples. Technology-wise, nothing at all prevents batteries from being created in the Bronze Age. Power generation might have to wait until the Iron Age, but you can do a lot with just a few cells. And all the pieces were certainly in place in medieval times. The biggest problem after making the things would be finding a use for them, but humans are ingenious creatures. They’d work something out.

Future past: Introduction

With the “Magic and Tech” series on hiatus right now (mostly because I can’t think of anything else to write in it), I had the idea of taking a look at a different type of “retro” technological development. In this case, I want to look at different technologies that we associate with our modern world, and see just how much—or how little—advancement they truly require. In other words, let’s see just what could be made by the ancients, or by medieval cultures, or in the Renaissance.

I’ve been fascinated by this subject for many years, ever since I read the excellent book Lost Discoveries. And it’s very much a worldbuilding pursuit, especially if you’re building a non-Earth human culture or an alternate history. (Or both, in the case of my Otherworld series.) As I’ve looked into this particular topic, I’ve found a few surprises, so this is my chance to share them with you, along with my thoughts on the matter

The way it works

Like “Magic and Tech”, this series (“Future Past”; you get no points for guessing the reference) will consist of an open-ended set of posts, mostly coming out whenever I decide to write them. Each post will be centered on a specific invention, concept, or discovery, rather than the much broader subjects of “Magic and Tech”. For example, the first will be that favorite of alt-historians: electricity. Others will include the steam engine, various types of power generation, and so on. Maybe you can’t get computers in the Bronze Age—assuming you don’t count the Antikythera mechanism—but you won’t believe what you can get.

Every post in the series will be divided into three main parts. First will come an introduction, where I lay out the boundaries of the topic and throw in a few notes about what’s to come. Next is a “theory” section: a brief description of the technology as we know it. Last and longest is the “practice” part, where we’ll look at just how far we can turn back the clock on the invention in question.

Hopefully, this will be as fun to read as it is to write. And I will get back to “Magic and Tech” at some point, probably early next year, but that will have to wait until I’m more inspired on that front. For now, let’s forget the fantasy magic and turn our eyes to the magic of invention.