Take a modern invention back in time

I’d give them a bunch of other things about satellites…sort of like taking the flux capacitor to Doc and seeing his face when he trots out the rough drawing he did after hitting his head on the toilet…

Knowledge of how to make good glass and grind it into lenses taken back (say - to Egypt at the time of the pyramids) would kick-start a lot of further discoveries in medicine, astronomy, and navigation. Primitive eyeglasses were also given credit for extending the working lives of the learned.

I wouldn’t go for lens glass, I think initially you would be better off going with other glass products, especially if you could tie this into grave goods or upscale goods for the nobility and wealthy elites. Think Roman glass, especially the really cool 3-dimensional glass they were able to make and carve…that would be huge, once you made some and got it into the right hands.

The trouble with both of these is you would need to learn Egyptian in the period you are targeting and probably take some sort of stake with you…gold or whatever…so you could set it up yourself and get it going yourself to prove to others it works. I doubt you would be able to entice the existing artisans to take on a project to make glass, say, as those guys already had plenty of business making shabti and other goods for the nobility and wealthy elites.

My thought on Egypt, especially old or middle kingdom, would be the overshot water wheel. Again, though, you’d need to build one yourself, so you’d need the resources to do it and get it going to really show its potential for things like threshing grain or even metalwork. You could, perhaps, kick start the iron age early if you had the resources. Tut had a meteor iron dagger that was so valuable to him it was on his person in his tomb…a VERY high-status item at the time. Focus on such things for the nobility initially and then expand as you have more resources. But it would be a ton of work. Be sure to get your shots up to date before going. :slight_smile:

AI agree that making really good glass is a tough thing to do, and you don’;t need it. The earliest lens was made of rock crystal (the Layard Lens). They have since found a Roman lens grinding factory in Egypt. Rock crystal lenses were the material of choice for glasses up until the 19th century – it was considered harder to break, more transparent, unlikely to discolor, and “cooler” on the eyes.

Also, the Romans used water-filled glass balls as magnifiers. We have documentary evidence for this, and several of the balls survived. The advantage here is that you can use the por-quality glass to make the spherical container, because the walls are pretty thin. You then fill it with pure clear water, and you have a much better magnifier than you’d get from trtying to make a sphere out of glass. And if the water starts to get cloudy and green with algae, you just empty it out and refill it.

Finally, you don’t really need glass or rock crystal lenses to correct bad vision. It’s much easier to make pinhole glasses or “monocles” out of ceramic, stone, shell, or leather. They don’t break as easily, and can easily be replaced. I strongly suspect this was a widely used remedy in the Roman world, and that many examples are simply not recognized as such when they’re found. I can point to examples of pinhole glasses from Centra;l Asia from way back.

So all you’d have to do to improve people’s vision if you go back in time is to popularize the use of pinhole glasses.

I think people are greatly underestimating how hard it would be to take any complex device and try to create it outside of its era.

Even if the device could technically be made earlier, the sheer number of parts, pieces, lubricants, tools, and specialized knowledge required even for mundane operations would be overwhelming. Every screw, every fastener would need to to be mass produced. Gasoline would need better refining. High quality bearings would beed to be designed. Metal strength can’t be inconsistent. Then there’s all the intermediate processes, chemicals etc that don’t show up in the final product but are absolutely critical to making it.

Here’s an example: What would happen if you took a Spitfire back to WWI? Not much, since it required 100 octane fuel, which wasn’t developed until 1940. In fact, one of the advantages allied planes had in WWII was access to 100 octane fuel.

Something as simple as a ball bearing would limit manufacturing any motorized device before the 1800’s. Making insulated wire is a fairly new process - so new that the house I lived in as a kid had exposed metal wiring on the walls (built in 1800’s). Vulcanized rubber wasn’t developed until the 1850’s, and plastics are a 20th century development.

For most modern devices, there is probably a hard limit for how far they could be taken back before building more of them would be a hopeless task.

For an extreme example, I think you could take an iPhone back to 1990 and give it to a young Wozniak and Jobs, and you’d probably not accelerate its development much at all. You might stop a few blind alleys from being followed, but we’d get consumer iphones at about the same time we did anyway. Too much tech had to be invented first.

Exactly. That’s why I was saying you would need to not just take the design back but the actual production process used. Most of the real work in developing, say, the M4 Sherman was really in how to produce the things quickly and in quantity. Basically, taking the thing apart, then figuring out how to organize the mass production lines and system, the logistics, and all the rest to actually build it. If you had that as well as the plans and upgrades it would really streamline things.

If you didn’t have any of that and wanted to, as a poster was saying up thread, take a process back into the past that the civilization didn’t really know about, you’d need to do it yourself really. It would be very hard to get anything like that going, and pretty much impossible to get craftsmen and the like to help do it in the time you are targeting. Not unless you also took back substantial capital you could use to buy what you needed help and materials wise, but that has a host of other issues.

They would have trouble with the basic materials and even the riveting process wrt aircraft grade. While some of the more advanced powers could, perhaps, produce a single Spitfire, no one could manufacture them. It would be a one-off. The same goes for the fuel, but it would really be the machine parts for the engine and aircraft skin and frame that would be the real issues from a mass production perspective.

Actually, the biggest things they would get out of it, IMHO, would be the interface. They wouldn’t be able to replicate any of the materials or even the software, but it would give them a huge jump on designing future interface paths. Since, essentially, their interface came from Xerox PARC (it also inspired Windows), it would be a huge help in that alone. ETA: Another thing might have been WiFi…I think the current phones will still do the older 802.11 protocols, and you would only need an RF scanner to be able to see what was going on. At a minimum, they would have had insights into the miniaturization potential for the various radios and wireless networking (I guess a 7 or so year head start on that).

But your broader point is correct…they wouldn’t have been able to use it to do much even if you took more than just the phone, as the materials science simply wasn’t there to enable them to create the chips or the software.

I learned primitive technologies such as friction fire methods in the 1990’s, from people like Jim Riggs, Richard Jamison and John McPherson, among others . I took what they said and spent hundreds of blistery field hours to make the techniques work with my local environs and florae. Then in the early 2000’s I studied Archeology and got my Masters, specializing in Experimental Archaeology. All this happened before YouTube, of which I have little use outside music.

After success became refinement, including specially chosen and tuned friction fire sets from local natural materials, that take only seconds to produce embers with. They are not average sets, they are special sets. Suboptimal sets, or suboptimal conditions (mostly high humidity) can take 30 or 60 seconds to produce an ember, not including possible prep time (gently drying the friction surfaces with low pressure rotation).

I haven’t done videos on this, but I have made hundreds and hundreds of primitive fires outdoors in four seasons (not the hotel), and dozens of primitive fires in front of live audiences. I have learned nothing from Youtube in this regard. The real expertise is far from there, much of it not even online.

I do know that the Primitive Technology guy, who’s videos you posted in your reply is NOT an expert in any regard. He has done a ton of stuff, learning by doing. After seeing him having no idea what species of plants he is using for his gear, and telling, for instance, that a bow and arrow set that is bordeline ethical to use on squirrels would be a good turkey hunting weapon, I know his advice isn’t worth much.

Youtube makes “experts” out of people who simply have lots of views on their videos. A guy I know specializing in Unboxing videos makes 20k per month off YT, such is the bizarre modern life.

Maybe I should become a Youtuber and get 345 views, making ancient fires the effective way.

So that I’m clear because I am still not from this post–you cannot in fact make a fire in less than 60 seconds out of twirling any two sticks, but rather sticks that are part of very specialized firestarting kits that you took years to learn how to setup and prepare?

Maybe I didn’t make myself clear, and Boy, a whiff of snark in the air, but no:

It does NOT take years to learn to setup and prepare Very Specialized kits to make friction fires quickly and efficiently. Starting from zero, and having zero personal instruction, it took me lots of sweaty hours to first succeed in making fires with two sticks. Then it took lots of additional hours spread over many seasons to make it quick and easy, and then quickly and easily done under real life conditions, such as late autumn Stone Age treks, where the hand drill was the only firemaking apparatus, and rain, sleet and snow were on the Boreal menu.

Second, and this is a biggie:

Using “any two sticks” to make a friction fire is a cartoon fantasy, and has always been. Let me repeat: NO-ONE can make fire by twirling any two sticks. Only carefully selected components that also fit materially together well, and have been shaped expertly, have any chance of working. Excellent technique, in other words efficient transfer of muscle energy into a tiny area between combustible materials, can make up for suboptimal components, but only so far.

The Hadza travel some 30 - 60 km on foot to go to the particular places up the mountainside that produce good hand drill materials. I don’t know of any environ where good friction fire materials were very widespread or common, although there may be some. But good materials are definitely “gatherable”, in that I can go into the woods in the morning and come back with a small bunch of usable materials by the evening. But not to dispair: hand drills are very durable: a single drill can make c. 30 - 100 fires before it’s exhausted. Hearth boards are somewhat quicker to need replacement.

Mankind has NEVER had anything but specialized firestarting kits, because they are needed to reliably have the most important tehcnology available when most needed.

People always ask: what woods do you use / should I use? But it’s much more subtle than that. For instance, the best hand drill materials are plants or plant parts that have a tough outer “skin” combined with a low-density pith.

Different ratios of skin vs. pith create huge differences in workability. Too thin, and the drill bit produces little dust and breaks easily Too thick, and the pressure and energy needed is just too high. Just right and the drill produces copious amounts of hot wood dust, while also grinds down and heats up efficiently, with moderate expenditure of energy. These are the sticks that give an ember in 10 - 20 seconds. They are not rare, nor are they difficult to prepare, once you know what to look for and where to find it.

This is just one of the dozens of variables with just the hand drills, no mention of the hearth board requirements.

I think what this points towards is that if you want to really make a difference you need to be thinking about very fundamental technologies, and even then you’re going to be limited in how far back you can push their development.

On the other hand, human beings are endlessly inventive, and respond well to incentives. We did develop plastics and ball bearings and systems of mass production after all. The question is really, could any of this have happened faster?

There’s the Candide view (“all is for the best in this, the best of all possible worlds”) that says there’s no real advantage possible - things developed pretty much as fast as they could. But of course R&D isn’t a perfectly linear process: there are dead ends and missed opportunities. For example, take Bakelite:

So you’ve got scientists interested in the right area and with the tech to experiment and produce new materials. But the first attempt is a non-starter. So what if our time traveller goes back and persuades Baekeland not to bother with Novolak and to try strengthening wood instead. It doesn’t do much, but it shaves some time off the development of the actually usable material.

That might not be the best example, but it’s probably possible to find some quite important tech that could have been invented 2 years earlier, some that could have been invented 5 years earlier and even an occasional nugget that could have come 10 years earlier. (And actually, the further back you go, the easier it is to push tech further back precisely because the rate of change is slower)

If you get plastics going in 1897 instead of 1907, say, what happens? Do the relevant technologies develop at the same rate, just 10 years earlier? Or do you get a cascade effect as the exponential curve of development kicks into gear? If you also bring forward as far as practicable oil refining, machine tools (i.e. fundamentals) you might not get a Spitfire as such in WWI but you might get faster, better planes. (Or indeed, you might not get WWI at all. Mess with the timeline at your peril).

So on the basis of fundamental technologies being the way to go:

How early can we push the alphabet? Hieroglyphics were ultimately a dead-end - if you went to Egypt in 3000BC (ignoring for a second the practical communication difficulties) could you steer towards a phonetic alphabet from the get-go?

The Chinese had the compass in c.2nd Century BC to 1st Century AD - but it wasn’t used for navigation until the 10th or 12th centuries AD. That has to be a candidate - the technology to manufacture a compass exists, just not the use. What happens if you go back and demonstrate it to Augustus?

Printing is another invention that wouldn’t have to be moved back very far to have a huge impact. Even 5 years would see a shift but as it was really using existing technology (e.g. wine presses) at first, then you could plausibly get it 10 or 20 years earlier which would have a huge exponential effect.

An interesting one is overland travel. Moving stuff around pre the canal era is enormously difficult. Local crop failures turned into famines because it was simply impossible to transport surplus food even from as near as 50 miles away at the speed and volumes needed. However, canals take manpower to dig which requires a certain level of surplus; steam engines are hugely technological complex. Better roads are another solution but also manpower heavy. I do wonder about railways - even without steam engines, putting wagons on rails is a big energy saver. But you’d need the right terrain and still a certain amount of manpower to lay the tracks. There are huge gains here but I don’t think there’s much of a solution.

That said, there’s no reason a society which built the pyramids couldn’t build the Suez Canal, (and I believe some early attempts were made) so it would be interesting to sell Rameses on that one and see what happens.

So that’s a reasonable response and makes sense, my impression from your first post was that with training it’s basically trivial to just stop wherever you are while on a journey (reminder that long ago before this diversion we were talking about giving Zippo lighters to people from Roman Imperial times) you could just snap a few sticks off a tree and have a roaring fire in a few seconds.

I would say in the context of sending technology back, the ancient Romans would find a zippo lighter quite useful, as I am not sure that there was widely practice “stone age” firestarting techniques that were used with any kind of universality in Rome (the Empire was huge with lots of semi-independent peoples living under its aegis, I’m sure some of them were familiar with primitive firestarting techniques.) We know from our history of the Romans who left behind artifacts in cities and written records, that they had metal firestarters (some of the ones that survived look a bit like a horseshoe) and also that there was a broad general practice at least in the settled areas of not trying to start fires. Meaning you generally tried to always have at a bare minimum some hot coals somewhere that you could get going again a lot easier than you could start a new fire.

So I do think a “typical” ancient Roman would find a zippo to be a good convenience tool. Now of course once it ran out of fuel it’d be useless, but it’d probably seem almost like magic to them or a time.

You could easily push the development of movable type back a hundred years or so. The idea was floating around Europe already. Gutenberg just made a couple of key innovations in how to cast the type and what alloys to use. Given how much that one thing changed the world, getting a jump on it could cause some major ripples.

Huh, did not know that.
Typical eurasian centric education and viewpoint on my part I guess.
Related, on further thinking, would various metal alloys have use? Anyway, I can’t get past the idea that something metallurgical is the way to go.

I don’t want to nitpick on spelling, but I just want to say that “Baron Wasteland” would be an awesome name for a supervillian.

Yeah, I’m just going to cut to the chase and send the flux capacitor itself back in time. I know it needs “1.21 jigawatts”, so initially it seems like it will not work to send it back 50000 years, but, the way I see it, “time” itself will be a thing of the “past”.

I read a short story, probably three decades ago. A man invented a time machine. He was a big fan of Sir Isaac Newton. He thought about how much more Newton could accomplish if he took him back a calculator. So he does. IIRC, the calculator had a small atomic device for power, and would self-destruct after a given time (Newton’s death?) He tries to sell Newton on the idea of the calculator, randomly choosing numbers for a calculation. Unfortunately…


The random calculation just happened to resolve to 666. Newton, a devout Christian, took ‘The Number of the Beast’ to prove that the time-traveller was a demon. I don’t recall if the time-traveller was killed, or if he barely escaped back to his own time. Newton threw the calculator into a river. Many years later, it self-destructed. People told ominous stories of a supernatural occurence in the river.

Get the best set of technical encyclopedia translated into several languages of the time you wish to go to. Bring them the knowledge. Not a gadget.
I have seen some technical books that explain from first methods of a process/idea to latest methods. A big trunk full of such books is a veritable fast forward.

Here’s a book you might want to consider. I’ve read it. It’s pretty good, but not good enough to rebuild civilization with

How to Invent Everything: A Survival Guide for the Stranded Time Traveler

by Ryan North

This thread made me think of a large softcover book I read so many decades ago. It devoted chapters to the timeline and methods of many discoveries and processes. Each chapter also illustrated so many other things to explain the methods and technology of the main topic. Had illustrations of various tools and systems for the purpose at different times. The amount of information was just staggering. But so well written and illustrated. My personal concepts and knowledge of so many things was expanded greatly. A how to from basic discovery to industrial process of multiple massively important things. I will definitely take a look at your recommended book.