This is wrong, but less wrong than I thought:
" Steam engines, for example, weren't invented until the 1700's because metals were so bad at the time that pressure vessels were impossible to make safe "
Not quite: the development of high-pressure engines was delayed, but the initial deployment if low pressure engines was an immediate success.
The first steam engines were, of course, atmospheric engines: fill a large piston with low-pressure steam, squirt cold water, and - whoosh! - the steam condenses to water and a pretty good vacuum, leaving the piston to be forced in by atmospheric pressure.
Inefficient? Actually, no. Heavy, yes: this is a building with an engine in it, not a locomotive; and slow. But good for pumping and acceptably efficient at it; beam engines remained in use as municipal pumping stations well into the twentieth century.
They were two or more orders of magnitude more efficient than a horse, given access to tons (but not tens of tons) per day of coal. You simply could not link up enough capstans and horses to do what an early beam engine did.
Crucially for our purposes, a working beam engine can be constructed by blacksmiths and coopers, with a little bit of skilled brasswork and solder for the valves. This is feasible and affordable, in Rome, with our limited start-up capital.
What we need next is a profitable application, and we can copy de Savary's business model as well as his first crude invention: drain a once-lucrative mine that's failing due to flooding.
The Romans had mines - huge ones for copper, in North Wales - and probaby silver elsewhere. If they had mines, they had flooding.
The question is whether we can travel back in time with a well-memorised geological map that shows the proximity of such an opportunity to any small (or large) coal measure.
So we might have an opportunity to make a lot of money from an abandoned and unprofitable enterprise that the owner will be delighted to sell or rent to us.
Note, also, that we're travelling back in time with some seriously useful - and profitable! - ideas about mining engineering in general.
Armed with a lot of money, we might just have the cash flow to kickstart an industrial economy in the region, and start constructing a reverberating furnace and a real machine shop with some interesting uses for good steel. High-pressure boilers included.
It's bad form to reply to my own post, but a strong cup of tea has invigorated me with some ideas that follow on from building the first working beam engine.
I'm introducing a second invention, halfway through, because you need something to pump industrial quantities of capital as well as water.
Firstly, you probably won't have the cashflow to purchase another mine and build another engine for at least a decade. Not unless you're mining silver, or there's a severe economic supply contraint on copper, tin, or whatever you're extracting, permitting you to mak...
A recent discussion post has compared the difficulty of an AI destroying modern human civilization to that of a modern human taking over the Roman Empire, with the implication that it is impossible.
The analogy has a few problems: first, modern humans don't have much greater raw intelligence than the Romans, only a bit more knowledge and tools; an AI would have a genuine intelligence advantage. Second, a high-tech civilization like ours offers many more ways for a genius to cause chaos than existed in classical Rome: it's more plausible that you can throw a few existing technologies together to create a superweapon than that Ptolemy could have done likewise, and there's no ancient Roman equivalent to hacking a nuclear launch system.
But taking over ancient Rome might serve as an interesting upper bound on the difficulty of an AI taking over modern civilization. And it's a theme of Harry Potter and the Methods of Rationality that rationalists should be able to come up with creative solutions to seemingly hard problems. So if Professor Quirrell offered it as an extra credit assignment, how would you take over Rome?
Here are the rules:
- You are thrown back in time to the year 1 AD. You can choose to arrive anywhere in the world, but your method of arrival cannot itself give an advantage (you can't appear in a flash of light in the middle of a religious ritual or anything).
- You do not start with Roman citizenship or any other legal record of your existence.
- You keep your original physical characteristics, including sex, height, and fitness. You will appear in period-appropriate dress of your choosing, and can't carry any artifacts with you. You may start with enough money to live a patrician lifestyle for a year.
- You are intellectually near-perfect. You know all human knowledge as of 2012. You speak fluent Latin (and all other languages of the day) and can orate as eloquently as Cicero or Demosthenes. You are a tactical genius of the order of Caesar and Napoleon. And you have infinite willpower and goal-directedness: aside from human necessities like sleep or food, you need never rest.
- You win if you either become Roman Emperor (and are acknowledged as such by most Romans), or if a state you control conquers the city of Rome. You lose if you die, of old age or otherwise, before completing either goal.