South-pointing chariot kit in Boing Boing Bazaar

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This South-pointing chariot kit is $59 in the Makers Market / Boing Boing Bazaar.

Do you know how a differential works? Would you believe that the Chinese invented one nearly three thousand years ago, and used it as a non-magnetic compass to keep track of north and south as they traveled?

The figure on top of this amazing machine maintains its orientation no matter which way the chariot is pulled, pushed, turned or even how fast. How it does this is via a clever application of gears and mathematical ratios that would have earned the awe and admiration of Pythagoras, Euclid and Aristotle themselves.

It took us exactly eight prototypes to get the gearing worked out properly -- a fortuitous number, since eight is also the luckiest number in Chinese traditions.

This model is a 1/10 scale reproduction of the South Pointing Chariot. The completed kit stands 14 inches tall, 14 inches long and 7 inches wide. It contains over 37 precision cut hardwood pieces (not including the gear teeth), and when properly constructed, it really works!

Examples of the South Pointing Chariot can be found in fine museums all over the world, and now you can have your own museum quality model for your personal display of ancient technology.

The Chinese South Pointing Chariot

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  1. That looks hella awesome, but I’m confused: Is there any way you can tell what tools and materials you need to make it? I see from the description that at least some of it comes in precut pieces, but that’s about all I could find clicking around.

    1. If anyone’s curious, I got a speedy e-mail reply from the manufacturer re: materials and tools needed:

      “All you need is a good pair of scissors (or wire cutters – wire cutters actually work better) a ruler, some sandpaper and some glue.”

  2. found a page via wikipedia with a little more info, don’t know if it’s of much help.

      1. hmmm. perhaps nobody wants to go south anymore nowadays.
        i had a quick lookie-through and saw a few diagrams, but no specific plans. perhaps they’re in there somewhere.

  3. Slight problem with this — you are only guaranteed correct orientation if both wheels always stay in contact with the ground. If this isn’t the case even for a short turn, the south facing chariot will be a random-direction facing chariot from then on. Did they periodically calibrate it in ancient times?

  4. Worse yet, Jonathan, you’re only guaranteed correct orientation if both wheels always touch the ground and there are NO HILLS AT ALL.

    The article above claims this apparatus was actually “used it as a non-magnetic compass,” but I find that hard to believe, and I can’t find any citations supporting that claim. If anyone is aware of any, they’d be worthwhile to add to the wikipedia article, especially explaining how the limitations were overcome in practice.

    Me, I don’t believe these was anything other than a courtly curiousity.

  5. They’ve got one of these you can play with at the Toronto science museum (a much larger, more intricate one, though I presume also a replica since you can try it out).

    As a kid I thought it was cool because it was a big, complicated wooden mechanical thing but was a little perplexed about its application – the problems with it were obvious even when I was a kid. As was pointed out already, if you lose contact with the ground you’re screwed.

    However, if you think a little bit more about how these might have actually been used, it seems likely that there would be a team of several soldiers in charge of the device, ensuring that if it were necessary to lift the wheels to get over an obstruction (or whatever) that one of them would hold the current setting (by pointing a stick or something) so that it could be properly set up again. They would also be watching it closely the whole time, naturally.

    Of course I have no idea, but that’s one possibility.

  6. When Nathan Sivin was teaching at MIT, I know he made one of these during the January Independent Activities Period one year.

    First learned of the south-facing chariot in Joseph Needham great series of books on science and technology in ancient China.

    I wonder whether such a south-facing chariot might have some uses in solar tracking.

  7. Based on the photo above, it looks like it would be useful on the golf course.

    I bet the knob on the top is for manual adjustment.

  8. This is really a really nice lasercut replica. I’ve never seen one of these before but i had heard of them.

  9. I see a youtube video of a Lego one – although it looks like it’s not perfectly ratio’d since it seems to get slightly off as the guy twirls it a few times. Still cool though.

  10. I know that word “chariot” is pretty sexy and all but if you can’t ride it, it isn’t a chariot.

    1. Actually, the “south pointing chariot” is a traditional name – it was not made up for this replica. And the definition of chariot does not require that it carry people. (Same with “car.”) It’s really just a wheeled vehicle.

      @Anon7, even Wikipedia states over and over again that it was used as a non-magnetic compass. Including references back to the 3rd century BC.

      1. I think his point is valid: imagine going partially up a hill, taking a left, going halfway around, and taking another left. Imagine for simplicity that the hill was a cylinder at the point of circumnavigation (can you tell I majored in physics?). The apparatus would think it had turned around, but would actually be going in the original direction. Obviously, hills are not cylinders, but depending on the slant the apparatus should still be fooled, no?

        1. Oh, I was mostly speaking to his comment that he didn’t see any references to it actually being used. I don’t know how accurate it would be over a long journey!

          On a hill, though, if you imagine that the hill is conical (probably a lot closer approximation to a hill than a cylinder!) then the outer wheel would be spinning faster than the inner wheel as you go around the hill. That should offset the left turns, so you would end up with the pointer still indicating the same direction. But I am not motivated enough to figure out the (admittedly beyond me) math.

          Surely it’s a finicky device, but as penguinchris posited, there would likely be a team of people monitoring the chariot.

          The ultimate silliness, though, is that the ancient Chinese had enough knowledge to come up with the magnetic compass, which would have been massively simpler and more practical. They didn’t develop it until the 2nd century and then didn’t use it for navigation until the 11th century. They had the pieces of knowledge and technology available but not the implementation.

          1. They had the pieces of knowledge and technology available but not the implementation.

            I always wonder if people in the future will say that about us: “How could they not have developed the Warp Drive? I mean, they had flourescent lights and LSD!”

  11. Not a mathematician by any means, but the further you went away from the origin of this, wouldn’t it get less accurate? Eventually it would not be pointing north at all, if you were travelling east, wouldn’t it be pointing to a point east of the north pole?

    If it worked perfectly I guess you could have it point back towards home, more or less.

  12. This is the earlier Anon, answering @dculberson:

    You’re right, I’m sorry for not clarifying: Wikipedia’s article does discuss “uses”, but they aren’t specific, or really very credible. In one section with some detailed uses, there’s an additional incredible claim of a “south pointing ship,” which is simply not believable.

    dculberson’s “conical hill” discussion is unfortunately also wrong. It will still lose accuracy on your conical hill. Not as much as on the cylindrical hill though, sure. Worse yet are banked or, more historically correct, unevenly rutted curves.

    I do not believe a team, no matter how skilled or careful can adjust or fix for this except in the most basic way.

  13. It’s hard for me to see how this is more useful or accurate than just knowing the sun rises in the East. Was this actually widely used, or just a toy for the court?

    1. Without having looked at any further sources, I’d assume that this thing could be “calibrated at dawn (check where the sun rises, point chariot accordingly), and then you’d have a compass that’s easily good enough for a day. But like I said, that’s just my initial thought after looking at this thing and reading through the comments.

  14. My understanding, gleaned from Larry Gonick’s (glib-sounding but very well referenced) Cartoon History of the Universe, is that these chariots were constructed such that the VIP riding in them would always face south – it being a sacred direction.
    “How’s the view?”
    “Always the same…”

  15. My favorite example is this clothes press from Herculaneum, used for squeezing the water out of laundry. (It looks odd because the wood is encased in plexiglass.) The Romans had signet rings and papyrus, and yet nobody thought: “Hey, let’s put these parts together and invent the printing press!”

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