# Forgotten knowledge, methods, technology, etc. **URL:** \ **Category:** Factual Questions\ **Created:** [June 20, 2012, 1:43am UTC](https://boards.straightdope.com/t/forgotten-knowledge-methods-technology-etc/625710 "2012-06-20T01:43:53Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\ **Post date:** [June 20, 2012, 1:43am UTC](https://boards.straightdope.com/t/forgotten-knowledge-methods-technology-etc/625710/1 "2012-06-20T01:43:53Z")
Inspired by [this thread](http://boards.straightdope.com/sdmb/showthread.php?t=655562): Civilizations come and go, and often knowledge comes and goes with them. What was the most important knowledge or advanced methods or technology that a civilization ever forgot? ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [June 20, 2012, 2:04am UTC](https://boards.straightdope.com/t/forgotten-knowledge-methods-technology-etc/625710/2 "2012-06-20T02:04:26Z")
It may not be the most important thing anyone’s ever forgotten, but it still amazes me that despite all the efforts of the Impossible Project, nobody has been able to recreate good instant film after Polaroid stopped making it. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [June 20, 2012, 2:10am UTC](https://boards.straightdope.com/t/forgotten-knowledge-methods-technology-etc/625710/3 "2012-06-20T02:10:39Z")
I believe they’ve solved the issue of Damascus Steel, and Egyptian Bronzes. But everything I’ve read still seems to be pretty vague about the actual nature of “Greek Fire” > [@](#): > > The impression made by Greek fire on the west European Crusaders was such that the name was applied to any sort of incendiary weapon,[1] including those used by Arabs, the Chinese, and the Mongols. These, however, were different mixtures and not the Byzantine formula, which was a closely guarded state secret, a secret which has been lost. The composition of Greek fire remains a matter of speculation and debate, with proposals including naphtha, quicklime, sulphur, and niter. Byzantine use of incendiary mixtures was distinguished by the use of pressurized siphons to project the liquid onto the enemy. > **[Greek fire](https://en.wikipedia.org/wiki/Greek_fire)** > > Greek fire was an incendiary weapon system used by the Byzantine Empire from the seventh to the fourteenth centuries. The recipe for Greek fire was a closely-guarded state secret; historians have variously speculated that it was based on saltpeter, sulfur, or quicklime, but most modern scholars agree that it was based on petroleum mixed with resins, comparable in composition to modern napalm. Byzantine sailors would toss grenades loaded with Greek fire onto enemy ships or spray it from tubes. Its... Even Adrienne Mayor’s book is pretty vague on the topic. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [June 20, 2012, 2:20am UTC](https://boards.straightdope.com/t/forgotten-knowledge-methods-technology-etc/625710/4 "2012-06-20T02:20:09Z")
Civilisations or cultures? Civilisations generally find it harder to lose technology because they generally have writing and they are also generally in contact with other civilisations. So it takes quit a lot for a civilisation to lose technology. Parts of the Roman Empire during the dark ages saw a massive reduction in their engineering ability, for example, and lost the ability to make large stone buildings, but that’s about the most extreme I can think of. Cultures, OTOH, can lose almost anything. Cultures have lost the ability to make fire, that’s pretty damn significant.. > [@gotpasswords](#): > > ``` > It may not be the most important thing anyone's ever forgotten, but it still amazes me that despite all the efforts of the Impossible Project, nobody has been able to recreate good instant film after Polaroid stopped making it. > > ``` That’s just a subjective judgement. Many people, including IP itself, will tell you that their Polaroid replacements are identical to the original, and that their new products are superior. IP even uses the same factory as Polaroid uses. IOW the technology is no more lost than the tehcnology needed to make a 1963 Oldmobile. ---
**Author:** ![coremelt](https://avatars.discourse-cdn.com/v4/letter/c/4491bb/32.png) [@coremelt](https://boards.straightdope.com/u/coremelt)\ **Post date:** [June 20, 2012, 2:25am UTC](https://boards.straightdope.com/t/forgotten-knowledge-methods-technology-etc/625710/5 "2012-06-20T02:25:00Z")
Roman concrete. Its weaker but longer lasting than modern concrete. Its use disappeared during the middle ages and we are only just in the last decades working out the exact methods to recreate it. [http://www.smithsonianmag.com/history-archaeology/The-Secrets-of-Ancient-Romes-Buildings.html](http://www.smithsonianmag.com/history-archaeology/The-Secrets-of-Ancient-Romes-Buildings.html) ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [June 20, 2012, 2:01pm UTC](https://boards.straightdope.com/t/forgotten-knowledge-methods-technology-etc/625710/6 "2012-06-20T14:01:44Z")
[QUOTE=Blake;] Many people, including IP itself, will tell you that their Polaroid replacements are identical to the original, and that their new products are superior. IP even uses the same factory as Polaroid uses. IOW the technology is no more lost than the tehcnology needed to make a 1963 Oldmobile. [/QUOTE] Maybe they’ve made big improvements in the few months, but the last time I saw any of Impossible’s film, the end results were washed out and blotchy. They admit it’s not as good as we were used to, and user reviews on Amazon agree. > [@Impossible](#): > > …it may show variances in color balance, saturation and contrast and a light dot pattern in the dark areas… > [@Assorted reviews on Amazon](#): > > …The color and quality of this film is wretched… …strange washed-out textures… …not a great contrast and all have that grey-yellowish hue… For the time being, the precise technology, chemistry and process needed to make a good replica of Polaroid film has been lost. There’s nothing at all “superior” about Impossible’s efforts if they admit to the color and contrast issues and make multiple warnings about how the photos must be immediately shielded from light, kept warm and not shaken for at least three minutes, whereas the original was good to go as soon as it popped out of the camera, and shaking did nothing but stir a small breeze. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [June 20, 2012, 2:12pm UTC](https://boards.straightdope.com/t/forgotten-knowledge-methods-technology-etc/625710/7 "2012-06-20T14:12:20Z")
> [@gotpasswords](#): > > For the time being, the precise technology, chemistry and process needed to make a good replica of Polaroid film has been lost. Has it in fact been truly lost - that is, no one alive knows exactly how to do it, and all written records of how to do it have been destroyed? Or does the Polaroid company still have detailed documents about the ingredients and process, but they’ve chosen not to reveal them to anyone else? ---
**Author:** ![AaronX](https://avatars.discourse-cdn.com/v4/letter/a/7bcc69/32.png) [@AaronX](https://boards.straightdope.com/u/AaronX)\ **Post date:** [June 20, 2012, 2:13pm UTC](https://boards.straightdope.com/t/forgotten-knowledge-methods-technology-etc/625710/8 "2012-06-20T14:13:29Z")
The Antikythera mechanism? [Antikythera mechanism - Wikipedia](http://en.wikipedia.org/wiki/Antikythera_mechanism) ---
**Author:** ![Dr.Drake](https://avatars.discourse-cdn.com/v4/letter/d/ad7895/32.png) [@Dr.Drake](https://boards.straightdope.com/u/Dr.Drake)\ **Post date:** [June 20, 2012, 2:20pm UTC](https://boards.straightdope.com/t/forgotten-knowledge-methods-technology-etc/625710/9 "2012-06-20T14:20:15Z")
Well, the ancient Greeks forgot how to write, which is why they went from Linear B to the Greek alphabet some centuries later. ---
**Author:** ![si\_blakely](https://avatars.discourse-cdn.com/v4/letter/s/d9b06d/32.png) [@si\_blakely](https://boards.straightdope.com/u/si_blakely)\ **Post date:** [June 20, 2012, 2:26pm UTC](https://boards.straightdope.com/t/forgotten-knowledge-methods-technology-etc/625710/10 "2012-06-20T14:26:50Z")
Sometimes it is not what has been forgotten, but what was not known in the first place. [FOGBANK](http://en.wikipedia.org/wiki/FOGBANK) is a foam material used in thermonuclear warheads. Production was stopped in 1989, and production lines decommissioned. When a warhead refurbishment program was instituted in 2000, production of FOGBANK was restarted. It took until 2009 for useful material to be produced. Not only were records and details lost, modern raw materials were much more refined than original feedstocks, and a contaminant in the original raw material proved to have a vital role in the correct production of FOGBANK material. It took 11 years for that knowledge to be lost, and 9 years to be recovered. Si ---
**Author:** ![Wendell\_Wagner](https://avatars.discourse-cdn.com/v4/letter/w/8491ac/32.png) [@Wendell\_Wagner](https://boards.straightdope.com/u/Wendell_Wagner)\ **Post date:** [June 20, 2012, 2:31pm UTC](https://boards.straightdope.com/t/forgotten-knowledge-methods-technology-etc/625710/11 "2012-06-20T14:31:19Z")
As I understand it, during the Greek Dark Ages, there was no written Greek and apparently no one understood the writing system that had formerly been used: > **[Greek Dark Ages](https://en.wikipedia.org/wiki/Greek_Dark_Ages)** > > The Greek Dark Ages was the period of Greek history from the end of the Mycenaean palatial civilization, around 1100 BC, to the beginning of the Archaic age, around 750 BC. Archaeological evidence shows a widespread collapse of Bronze Age civilization in the Eastern Mediterranean world at the outset of the period, as the great palaces and cities of the Mycenaeans were destroyed or abandoned. At around the same time, the Hittite civilization also suffered serious disruption, with cities from Tr It... However, I’m not an expert on this, so please correct me if I’m wrong. ---
**Author:** ![Wendell\_Wagner](https://avatars.discourse-cdn.com/v4/letter/w/8491ac/32.png) [@Wendell\_Wagner](https://boards.straightdope.com/u/Wendell_Wagner)\ **Post date:** [June 20, 2012, 2:32pm UTC](https://boards.straightdope.com/t/forgotten-knowledge-methods-technology-etc/625710/12 "2012-06-20T14:32:52Z")
Dr. Drake and I had simul-posts there. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [June 20, 2012, 2:40pm UTC](https://boards.straightdope.com/t/forgotten-knowledge-methods-technology-etc/625710/13 "2012-06-20T14:40:35Z")
> [@si\_blakely](#): > > Sometimes it is not what has been forgotten, but what was not known in the first place. > [FOGBANK](http://en.wikipedia.org/wiki/FOGBANK) is a foam material used in thermonuclear warheads. Production was stopped in 1989, and production lines decommissioned. When a warhead refurbishment program was instituted in 2000, production of FOGBANK was restarted. It took until 2009 for useful material to be produced. Not only were records and details lost, modern raw materials were much more refined than original feedstocks, and a contaminant in the original raw material proved to have a vital role in the correct production of FOGBANK material. > > It took 11 years for that knowledge to be lost, and 9 years to be recovered. > > Si Sounds like the problem Dr. Jeckyll had with his ingredients. ---
**Author:** ![MLS](https://avatars.discourse-cdn.com/v4/letter/m/919ad9/32.png) [@MLS](https://boards.straightdope.com/u/MLS)\ **Post date:** [June 20, 2012, 2:42pm UTC](https://boards.straightdope.com/t/forgotten-knowledge-methods-technology-etc/625710/14 "2012-06-20T14:42:48Z")
I’ve been told that the actual formula for the beautiful stained glass used in the great cathedrals in Europe is lost. No cite, I could be wrong. ---
**Author:** ![Bridget\_Burke](https://avatars.discourse-cdn.com/v4/letter/b/7cd45c/32.png) [@Bridget\_Burke](https://boards.straightdope.com/u/Bridget_Burke)\ **Post date:** [June 20, 2012, 3:00pm UTC](https://boards.straightdope.com/t/forgotten-knowledge-methods-technology-etc/625710/15 "2012-06-20T15:00:14Z")
> [@MLS](#): > > I’ve been told that the actual formula for the beautiful stained glass used in the great cathedrals in Europe is lost. No cite, I could be wrong. Is seemed to remember a discussion–it happened [here](http://boards.straightdope.com/sdmb/showthread.php?t=585934)! All those brains couldn’t come up with any actual “lost” stained glass techniques. Washington DC’s [National Cathedral](http://www.nationalcathedral.org/visit/onlineTours.shtml) is full of stained glass–& it was begun in the 20th century… ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [June 20, 2012, 3:05pm UTC](https://boards.straightdope.com/t/forgotten-knowledge-methods-technology-etc/625710/16 "2012-06-20T15:05:50Z")
Have a look at this book, Theophilus’ **On Divers Arts** – it’s a contemporary book telling you how to make stained glass (and lots of other stuff) – the one I referred to in the previous thread > **[On Divers Arts (Dover Art Instruction): Theophilus, John G. Hawthorne, C. S....](https://www.amazon.com/Divers-Arts-Dover-Art-Instruction/dp/0486237842)** > > On Divers Arts (Dover Art Instruction) \[Theophilus, John G. Hawthorne, C. S. Smith\] on Amazon.com. \*FREE\* shipping on qualifying offers. On Divers Arts (Dover Art Instruction) ---
**Author:** ![AK84](https://avatars.discourse-cdn.com/v4/letter/a/85e7bf/32.png) [@AK84](https://boards.straightdope.com/u/AK84)\ **Post date:** [June 20, 2012, 3:15pm UTC](https://boards.straightdope.com/t/forgotten-knowledge-methods-technology-etc/625710/17 "2012-06-20T15:15:31Z")
I need to ask, do you mean the technology to perform a task. Or a specific way of doing so. many of the things, Roman Concrete, Greeks fire or Damascus steel are not strictly speaking list, we have things which do their job better in many ways. What we have lost is the specific way that was made. ---
**Author:** ![billfish678](https://avatars.discourse-cdn.com/v4/letter/b/7bcc69/32.png) [@billfish678](https://boards.straightdope.com/u/billfish678)\ **Post date:** [June 20, 2012, 3:18pm UTC](https://boards.straightdope.com/t/forgotten-knowledge-methods-technology-etc/625710/18 "2012-06-20T15:18:15Z")
Go read post number 239. It’s even happened right here on the Dope! [http://boards.straightdope.com/sdmb/showthread.php?t=655746&page=5](http://boards.straightdope.com/sdmb/showthread.php?t=655746&page=5) ---
**Author:** ![ralph124c](https://avatars.discourse-cdn.com/v4/letter/r/8797f3/32.png) [@ralph124c](https://boards.straightdope.com/u/ralph124c)\ **Post date:** [June 20, 2012, 3:19pm UTC](https://boards.straightdope.com/t/forgotten-knowledge-methods-technology-etc/625710/19 "2012-06-20T15:19:19Z")
The ancient Bolivians:[File:Zonnepoort tiwanaku.jpg - Wikipedia](http://en.wikipedia.org/wiki/File:Zonnepoort_tiwanaku.jpg) seem to have been able to finish cut stone to an extraordinary degree of flatness. I have never seen an explanation of how this was done (with only stone tools) Later structures (Inca fitted blocks) are impressively worked, but nothing like what is seen at Tiwanaku. How did they do it? ---
**Author:** ![jackdavinci](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackdavinci/32/3259_2.png) [@jackdavinci](https://boards.straightdope.com/u/jackdavinci)\ **Post date:** [June 20, 2012, 4:36pm UTC](https://boards.straightdope.com/t/forgotten-knowledge-methods-technology-etc/625710/20 "2012-06-20T16:36:45Z")
> [@ralph124c](#): > > The ancient Bolivians:[File:Zonnepoort tiwanaku.jpg - Wikipedia](http://en.wikipedia.org/wiki/File:Zonnepoort_tiwanaku.jpg) > seem to have been able to finish cut stone to an extraordinary degree of flatness. I have never seen an explanation of how this was done (with only stone tools) > Later structures (Inca fitted blocks) are impressively worked, but nothing like what is seen at Tiwanaku. > How did they do it? I read something to the effect of, if you move the stone back and forth in place, it naturally smooths away any imperfections in fit. [Next page](https://boards.straightdope.com/t/forgotten-knowledge-methods-technology-etc/625710.md?page=2)