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How Ancient Mechanics Thought About Machines

Posted by kdawson on from the first-practice-then-theory dept.

friedo writes "The NYTimes has an interesting piece about Prof. Mark Schiefsky, a Harvard classicist with an interest in the history of science. Schiefsky pores over ancient texts in Greek, Latin, and Arabic to decipher the origin of knowledge that's been taken for granted for millennia. For example, a Greek treatise published a generation before Archimedes' proofs of the lever laws explains why, if you were a galley slave, you'd want to work the oars near the center of the ship instead of closer to the hull."

29 of 76 comments (clear)

  1. Oh, the irony! by Chris+Burke · · Score: 4, Funny

    "For example, a Greek treatise published a generation before Archimedes' proofs of the lever laws explains why, if you were a galley slave, you'd want to work the oars near the center of the ship instead of closer to the hull."

    Not a very useful treatise since if you were a galley slave, you probably couldn't read! Oh, and they wouldn't let you off the ship to visit the library and check out the treatise anyway.

    Those poor, poor galley slaves.

    --

    The enemies of Democracy are
    1. Re:Oh, the irony! by mschuyler · · Score: 4, Insightful

      The galley slaves didn't need to read about it. They knew by experience. This proof was for the academics who only thought about rowing, but were not condemned to do it.

      --
      How about a moderation of -1 pedantic.
    2. Re:Oh, the irony! by techno-vampire · · Score: 2, Informative

      This, of course, ignores the fact that in Greek times the oarsmen of a ship were paid professionals, not slaves. I doubt that there were any galley slaves in the Greek ships that won the battle of Salamis. Not sure about the Persians, though.

      --
      Good, inexpensive web hosting
    3. Re:Oh, the irony! by spun · · Score: 4, Interesting

      Ah, but maybe you were an educated person taken as a prisoner of war and enslaved. Perhaps you'd already read the treatise, perhaps whilst helping prepare for said war. Then, you see, you could politely ask your overseer to let you work the inside of the oars. Being suitably impressed with your grasp of physics, they would undoubtedly let you do so.

      The problem is, you would rapidly figure out that you were badly mistaken in your choice. Working the inside oar gives mechanical advantage, sure, but what does that mean? You trade distance for effort. You are literally running back and forth while the guy near the edge barely moves.

      This is well documented in later times when countries actually used galley slaves instead of free citizens like the Greeks used. The Greek oarsmen worked one to an oar, and each had to be well trained and motivated to work together efficiently. All the rowing positions in Greek galleys were nearly equidistant from the fulcrum. The oars in larger Greek galleys were arranged in banks, one above the other. In Roman or Turkish galleys, oars were manned by groups of slaves, and in this case the outermost position was the most desirable as it required the least movement and effort. In Greek galleys, the most desirable position was on the uppermost bank of oars because you didn't have your face pressed into the ass of the guy above you.

      --
      - None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
    4. Re:Oh, the irony! by Petrushka · · Score: 3, Informative

      You're thinking of Athens, not of Greece generally, and even Athens used slaves in its navy. Hence the social importance of the battle of Arginousai: after the battle the assembly voted to give freedom to slaves who fought in the battle.

  2. Working conditions by The+Ancients · · Score: 3, Funny

    For example, a Greek treatise published a generation before Archimedes' proofs of the lever laws explains why, if you were a galley slave, you'd want to work the oars near the center of the ship instead of closer to the hull."

    Do you think it was mentioned in their induction pack along with their sunscreen, sunhat, and timecard?

    --
    The Mothership
    1. Re:Working conditions by elronxenu · · Score: 3, Funny

      ... and sample TPS report cover sheets.

      (That's TPS as in Trireme Propulsion System)

  3. Galley slaves had other worries... by TripMaster+Monkey · · Score: 2, Insightful

    For example, a Greek treatise published a generation before Archimedes' proofs of the lever laws explains why, if you were a galley slave, you'd want to work the oars near the center of the ship instead of closer to the hull.

    You'd want to be near the center of the ship only if you were interested in being more efficient at your slave job. Since the slave near the hull has to move his arms over a lesser distance, it could be argued that the hull seat was the better one.

    Of course, if you were rammed by another ship, you'd have a greater chance of being killed or sustaining horrible injury if you were in the hull seat...but since a rammed ship usually sank, and the galley slaves were usually chained to their oars, the outcome would probably be much the same, in the end...

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    ____

    ~ |rip/\/\aster /\/\onkey

    1. Re:Galley slaves had other worries... by mschuyler · · Score: 2, Insightful

      You obviously didn't read the article:

      "That took scholars to figure out. "Think of the oar as a lever," Prof. Mark Schiefsky of the Harvard classics department said. "Think of the oarlock as a fulcrum, and think of the sea as the weight."

      The longer the lever arm on the rower's side of the fulcrum, the easier to move the weight. In the middle of the ship, as the rowers knew, the distance from hands to oarlock was longest.

      This explanation is given in Problem 4 of the classical Greek treatise "Mechanical Problems," from the third century B.C., the first known text on the science of mechanics and the first to explain how a lever works. It preceded, by at least a generation, Archimedes' "On the Equilibrium of Plane Figures," which presented the first formal proof of the law of the lever.

      --
      How about a moderation of -1 pedantic.
    2. Re:Galley slaves had other worries... by jtev · · Score: 4, Interesting

      Being in the center has other benifits as well. You get the first chance at the gruel, you have one side of your body not being crushed up against the other galley slaves, all sorts of goodness. And one downside as well though. You're closer to the overseer's whip. So, I guess it evens out.

      --
      That which is done from love exists beyond good and evil
  4. Library of Alexandria by Bananatree3 · · Score: 4, Informative
    Only a tiny, tiny fraction of the books and scrolls within the Library of Alexandria survived, and who knows what kind of complex science and engineering was put into those books. The day it burned the world lost the greatest knowledge resource at the time.

    The History channel has a program on some of these amazingly complex ancient machines

    1. Re:Library of Alexandria by Anonymous Coward · · Score: 2, Funny

      Only a tiny, tiny fraction of the books and scrolls within the Library of Alexandria survived, and who knows what kind of complex science and engineering was put into those books. The day it burned the world lost the greatest knowledge resource at the time.

      For example, the recipe for fireproof paper.

    2. Re:Library of Alexandria by readin · · Score: 4, Interesting

      Only a tiny, tiny fraction of the books and scrolls within the Library of Alexandria survived, and who knows what kind of complex science and engineering was put into those books. The day it burned the world lost the greatest knowledge resource at the time.

      Ever wonder how much knowledge was lost when the ancient Chinese burned all their books? http://en.wikipedia.org/wiki/To_burn_the_classics_and_to_bury_the_scholars

      --
      I often don't like the choices people make, but I like the fact that people make choices. That's why I'm a conservative.
    3. Re:Library of Alexandria by trongey · · Score: 2, Funny

      ...who knows what kind of complex science and engineering was put into those books... On the other hand, if we assume that nerds have always been pretty much the same, then we can extrapolate that most of what we lost was pr0n and strategy guides.
      --
      You never really know how close to the edge you can go until you fall off.
  5. Not all slaves would be illiterate ... by pbhj · · Score: 2, Insightful

    I'm no historian but I think it's fair to say that slaves come via a variety of routes. For example being captured in a war. Abducted by pirates (the non copyright infringing kind). Simply abducted by people pulling a boat up at your village, killing a few people and carrying you off (do they count as pirates?).

    Now granted literacy through the ages hasn't perhaps been as high as it could but some of those galley slaves are going to be literates that couldn't be trusted with book work or who's masters wished to drive into the deck.

    Your point on access to the library is probably valid. But as they say "information wants to be free" ...

    I would say as a tyrannical slave-master I'd want to get the best from each slave, or know where to put those most in need of subduing.

    1. Re:Not all slaves would be illiterate ... by kalidasa · · Score: 2, Interesting

      Literacy rates in the fourth century aren't known, but for Athens itself, at least, the literacy rates might have been very high. There is a lot of controversy on this subject. We do know that a number of dramatic works intended for public production introduced characters about whom a point was made that they could not read, but we aren't sure if their illiteracy was intended as comic relief (if illiteracy was unusual) or just a marker of class or status (if illiteracy was common). Keep in mind that the Athenians kept a lot of written monuments (stelai and the like) - there would be no point to them if literacy rates were *very* poor. However, I'm pretty sure there were NO borrowing libraries: what libraries there were tended to be private. Alexandria is the exception - but even it was most certainly not a circulating library, and it's later than this treatise.

    2. Re:Not all slaves would be illiterate ... by trb · · Score: 3, Funny
      Literacy rates in the fourth century aren't known, but for Athens itself, at least, the literacy rates might have been very high.

      Of course they were literate. They knew ancient Greek!

  6. Re:Galley slaves had other worries... THE WHIP by Anonymous Coward · · Score: 2, Funny

    Well, think about it.. you have more than 1 slave per oar.
    Work = force x distance. It's the same amount of WORK whether
    you push the oar on the end, the middle, or anywhere else.

    The guy closer to the hull has to exert more force, but over less distance.
    When the pace picks up and the guy in the middle is flying out of his seat
    with every revolution trying to pull an oar around 5 feet sweeps, the slave
    by the hull is comfortably sitting on his bench.

    Noted, he must be STRONGER than the slave to the middle, but the same work
    is being done by each slave on the oar. If not, that's what the whip is for.
    And it's a lot harder to whip the guy by the hull.

    All you scholars and ivory tower slavedrivers need a few cracks of the whip
    to REALLY understand the physics of being a galley slave.

  7. And here's some good pics to illustrate the point by spun · · Score: 3, Interesting

    http://graymonk.mu.nu/archives/2007/01/roman_navy_on_t.html

    http://graymonk.mu.nu/archives/2007/01/superb_models.html

    Look at the oars in all three cases. They are almost exactly the same length throughout each ship.

    --
    - None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
  8. Galley slave would want to be toward the hull by GargamelSpaceman · · Score: 2, Insightful

    A galley slave doesn't give a damn whether the boat goes fast or slow. He just wants to look like he is working whilst working the least.

    So since the lever moves the furthest distance near the center, the motion is greater, meaning more work. Also the effects of a slave pretending to row are felt most acutely when the slave is seated in the middle of the boat.

    Also, the guy with the whip is closest to the slaves in the center, however having some distance between the whipper and the whippee may make the speed of the lash higher for slaves further away.

    Another consideration is whether being near the hull of the boat conferred any advantages/disadvantages in terms of ventilation/warmth/being out of the rain/being in the rain/etc.

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    ...
    1. Re:Galley slave would want to be toward the hull by epine · · Score: 5, Interesting
      I have to say that NYTimes article is a spectacularly good example of bad science writing. Without halfway trying, it manages to regress conservation of energy in the mind of the lay public by 200 years.

      The optimal product of force through distance ultimately depends upon build (body type). Most likely the lanky rowers will be positioned at the long end of the level arm, while the stocky people are positioned with shorter lever arms.

      Since you probably aren't being fed enough, your primary risk is starvation through overwork. It wouldn't surprise me that rations were set low enough that many rowers had short careers, once they burned out their physical reserves. That was certainly the implication in Ben Hur.

      Since you have to maintain cadence with the rest of the oars, your option to cheat is to catch late and release early. You can bet the guy with the whip has a keen eye for shading on stroke length (duration with blade submerged).

      I've stroked an eight before. Even without being able to see anyone behind me, I had a pretty good idea who was pulling their weight and who had good form. At the elite level, I'm told everyone knows who pulled a good race.

      In Primo Levi's books he talks about the hazards of being teamed up with the nearly goners: the ones who haven't got enough left to pull their share, and worse, the ones who no longer cared about life enough to slack for every extra second possible.

      It would be a bit different sharing an oar than lugging railway ties in the snow with half a shirt.

      Probably your best situation was to be paired up with the rookie who doesn't know his 4000 calorie work day is going to be rewarded with a 1500 calorie dinner. Until the third day when he faints and you get to pull both shares all by yourself.

      http://en.wikipedia.org/wiki/Sawmill

      Prior to the invention of the sawmill, boards were rived and planed, or more often sawn by two men with a whipsaw, using saddleblocks to hold the log, and a pit for the pitman who worked below. Sawing was slow, and required strong and enduring men. The topsawer had to be the stronger of the two because the saw was pulled in turn by each man, and the lower had the advantage of gravity. The topsawyer also had to guide the saw so that the board was of even thickness. This was often done by following a chalkline. I was once told a story by a great ancestor that after a few weeks, the topsaw guy became so muscular he beat the crap out of the guy below, so the roles would often reverse, but that more often than not, the muscular guys took the easy jobs, and the small guys either ended up built like pit bulls, or were short for this world.

      Anyways, if I'm reincarnated on a slave galley, I'd like to have that NYTimes reporter sitting beside me on the "desirable" side with the long lever arm, to discover the bio-mechanical joys of finishing your stroke at a 45 degree abdominal recline while I dent his head with my elbow every time he slacks off.
    2. Re:Galley slave would want to be toward the hull by icegreentea · · Score: 4, Informative

      Completely true. A galley slave really wouldn't care. Which is why the Greek States by and large didn't use slaves. Almost all oarsmen were freemen, and they had to be somewhat professional. Athens (for example) built its wealth and its 'empire' on its navy, and thus there was a sense of pride in serving the navy. Not to mention, when you have 170 oarsmen, they have to work as a coherent team. Getting 170 slaves who really don't want to be there to work properly would be detrimental. In cases where slaves were pressed into service (in emergencies or what not) they were sometimes rewarded with freedom after serving.

    3. Re:Galley slave would want to be toward the hull by colinrichardday · · Score: 4, Funny

      Oh sure, drag facts and logic into Slashdot.

  9. Other great knowlege repositories by gmezero · · Score: 3, Interesting

    It's documented that the missionaries actively destroyed Mayan literature as being pagan works of the devil. The small scraps left hint at materials that might have touched on everything from law to stellar cartography.

    1. Re:Other great knowlege repositories by jd · · Score: 2, Interesting
      Not just Mayan, but virtually all Mesoamerican writings. They also burned the vast majority of writings on Easter Island, rendering the language unreadable even today. (We actually know a little Mayan, although little is hopelessly optimistic.) As people might have realized by now, I get rather upset when knowledge is lost - especially in fire.

      We do know a few things about the Great Library of Alexandria - they had a theory of robotics, a copy of the Old Testament many times larger than all known books from that work, they probably had substantial texts on sun-centered solar systems (they'd worked on that for a long time), and since one rather mysterious artifact has been shown to have had differential gearing inside, I'm willing to bet they had substantial texts on such systems. Although Greek society was notoriously patriarchial, it is also known that there were female chief scientists, chief librarians and teachers. Whether they could have broken through their mindset will never be known, but their achievements in liberal, equalitarian science were unrivalled by many western nations until the 19th and 20th centuries and compare well with some parts of the world today.

      We don't know all the books were lost - the Archimedes Palimset shows that, and there are tales of many rotting and unreadable (by conventional means) documents in rubbish tips of Ancient Greece. Whether there will ever be a full study to see if other salvagable recorded history is out there, I don't know. It hasn't happened yet, and time only reduces what might have survived. I would argue that it is possible we could recover far more material than we currently have, but impossible if - as is happening - nothing is happening.

      --
      It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
    2. Re:Other great knowlege repositories by TapeCutter · · Score: 2, Informative

      "they never even invented the wheel"

      So how do you explain wheels on Mayan toys?

      --
      And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
    3. Re:Other great knowlege repositories by colinrichardday · · Score: 2, Interesting

      So, no: the Spanish did not have anything to learn from the Mayans regarding number systems in the 1500s. They had already known it for 600 years! It was no longer an exciting new technology.

      And you are correct only if the Mayans did not make further progress. What did they achieve in the intervening centuries?

      (By comparison, calculus was found by Newton only 320 years ago.)

      Not if Leibniz discovered it earlier! Now where did I put that flame-retardant suit?

  10. Apart from the physics by Centurix · · Score: 2, Funny

    The last thing you need is to be sat in the middle seat between two really fat slaves...

    They probably had more leg room on those ship than we do in cattle class now. And I bet they could take fluids on board too.

    --
    Task Mangler
  11. Being a bastard and jumping in OT by drachenstern · · Score: 2, Interesting

    This has got to be the highest percentage of users with a UID less than mine to have posted in a single thread in a long time. I haven't counted, but over half of the posts as of the 60 post count mark were by users with a UID less than mine, which is WILD!

    Yeah, I'm quite aware that this post was OT, I was just looking to get it pretty high up on the discussion. I know how to game /. well enough too!

    As far as the article, I'm surprised no-one has mentioned the Yonaguni civilization and what may have been lost from even back then!!?!?!! Well, of course, there is no guarantee that there actually was a civilization, but when it comes to how the ancients thought about machines, I'm more interested in the older civilizations and how they may have spread around the world into the civilizations that we all "know". Here's a clickie for those that don't know about Yonaguni (sorry for the paranoid site reference, but it's informative and has lots of viewables): http://www.morien-institute.org/yonaguni.html

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    2^3 * 31 * 647