

Lost technologies - auxbuss
http://www.toptenz.net/top-10-lost-technologies.php

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adolph
It is interesting how many things are "lost" due to missing meta-data.

Summary:

10\. Stradivari: leading hypothesis seems to be that the density of the
particular wood used accounts for the sound.

9\. Nepenthe: most likely still used today, but historians are unable to
pinpoint just what modern substance the Greeks were referring to

8\. Antikythera: true purpose is still not fully known

7\. Telharmonium: public’s fascination with the device waned

6\. Library of Alexandria: contents burned sometime around the first or second
century AD. Scholars are still uncertain just how the fire was started

5\. Damascus Steel: supply of ores needed for the special recipe for Damascus
steel started running low, and sword makers were forced to develop other
techniques

4\. Apollo/Gemini Space Program Technology: just because modern scientists
have the parts doesn’t mean they have the knowledge to understand how or why
they worked the way they did

3\. Silphium: scarcity, combined with an overwhelming demand, more than likely
led to over harvesting, which drove the plant into extinction

2\. Roman Cement: recipe for concrete was lost during the descent into the
Dark Ages

1\. Greek Fire: weapon’s use seems to disappear after the decline of the
Byzantine Empire, but just why still isn’t known

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auxbuss
Fascinating that NASA are now having to reverse engineer existing spacecraft
parts that they have lying around in junkyards, since they forewent the
opportunity to document during development, apparently due delivery pressure
and use of contractors.

~~~
hga
Actually, when it came to the Saturn V rocket NASA deliberately destroyed the
design documents in a "burn your boats" style to make the Space Shuttle the
only way forward. Disbanded Wernher von Braun's team for good measure.

Which is a pity, seeing as how some of the details of the design of the first
stage kerosene/LOX F-1 engines were said to be pretty well near magic (it had
7 years of teething problems according to Wikipedia).

On the other hand I know from an acquaintance that the NERVA developers
including her father were gathered together no later than in the '80s so that
their work could be adequately documented.

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arethuza
I'd add Vitrified Forts to that list:
<http://en.wikipedia.org/wiki/Vitrified_fort>

Fortresses built with stone walls that have been melted together - presumably
on purpose.

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stcredzero
This article is a bit off on one part. Damascus steel has in fact been
reproduced, at least in part. (There's one southern blacksmith who did a demo
on a documentary with a hydraulic press and his recreated Damascus blade
cutting through cheap blades.)

One of the key reasons why the "recipe was lost" was that a part of the recipe
resided in the hands of Indian suppliers of wootz. The Indian suppliers were
managing to put trace amounts of vanadium into the steel, but then somehow
changed their process so that this stopped. After that point, no one could
make Damascus blades anymore.

Contrast this with Japanese swordsmiths, who maintain close relationships with
their smelters. (Supplier relationships were supposed to be one of the keys to
the modern Japanese economic success.)

