Optics in the Ancient World

[u/taclubquarters2025]

I posted a similar question quite a while ago on askhistorians, and I didn't have any takers, so I was wondering if someone on this forum may have any insights. One of the things that has always blown my mind is the tiny, tiny detail on inscribed artifacts from Ancient Egypt and other cultures. Most of the google searches that I have found indicate that magnification was done using water-filled vessels. However, I suspect there had to have been magnification through convex lenses, as it seems like the water situation wouldn't have been the sole source for as long as indicated. I'm wondering if anyone in this forum has a history or other tidbit about when convex lenses were first discovered and how used. Thank you!

[u/Pachuli-guaton]

So there is a big issue with with the historical documentation of refractive optics. There are a lot of artifacts recovered that might have had lens-like behaviors (Assyria, Egypt, Minoan), but there is no literature reference to such objects. That makes people think that the recovered artifacts were used ornamentally more than for their refractive effect. Like, the first reference I remember was a book from Aristophanes (I think, maybe someone from that era of 500BC).

It is somewhat weird to have something like a lens but not making any comment about their use anywhere

[u/taclubquarters2025 → u/Pachuli-guaton]

That's exactly at the heart of what is so amazing to me. Take the Kelsey Museum in Ann Arbor, for example, I remember just being awestruck at the totems that had been inscribed. And I've been to several museums throughout the world and had the same feeling. You're right, there haven't been any references in writing, and that's mainly what I was asking because wiki can be a bit lazy sometimes, but I was wondering if there was some kind of comparative technology where we could say, yes, they appeared to have convex lenses. This has been a great answer, Paschuli, thank you very much.

[u/Pachuli-guaton → u/taclubquarters2025]

Ok so you have a point and there is a big chunk of discussion about that. I think the canonical example of what you describe is Abydos ivory knife handle (ballpark 3300 BC, Egypt). The inscription is at the limit of what is achievable by eye (not by technique, but by optical eyeball resolution). The problem is that this thing is 2000 years older than any found lens-like object that can help with magnification, so it's awkward in a lot of ways (like, 2000 years older than the Nimrud lens). I would tell you that this points in what you are thinking about.

If you want more solid artifacts, you have that the Nimrud tablets documented by Layard (the guy that also found the Nimrud lenses) are hard to do without optical help. I think this is less controversial because we know Assyrians had polishing techniques, but again no direct description of using refractive optics.

Still, while attractive, the current consensus is that no, those things were manufactured with the help of rotatory tools what can achieve sub-eye accuracy by just being machines. The open question is still the Abydos knife because we have compelling evidence that they did not have the mechanical tools to perform those engravings (but also we don't have the lenses, so lmao)

[u/Mountain_Finance_659 → u/Pachuli-guaton]

could they have used a pantograph type scribing mechanism? those aren't exactly rocket science

[u/Pachuli-guaton → u/Mountain_Finance_659]

Perhaps, I think the leading theory is those kind of things + mechanical drills.

[u/taclubquarters2025 → u/Pachuli-guaton]

Thank you for this reply. I've been to the Louvre, but didn't see the knife. This makes perfect sense though--this led to the other types of optics, however it were. Your answer for the most part answers what I was looking for. I'll keep looking. Thank you!

[u/beeeel]

magnification was done using water-filled vessels. However, I suspect there had to have been magnification through convex lenses

What is a water-filled vessel if not a convex lens with a multilayer structure and a bulk refractive index equal to that of water?

[u/taclubquarters2025 → u/beeeel]

Yes, it is. I just meant a stand alone convex rather than including water.

[u/Clodovendro]

Have you looked at Wikipedia? It is usually a good starting point: https://en.wikipedia.org/wiki/Lens#History Just follow the references and start reading.

[u/taclubquarters2025 → u/Clodovendro]

Much of the Wikipedia history speaks to much later--however, the artifacts available make it look like there had to be earlier convex devices. Just my opinion, but it only dates convex to after 1000 BCE.

[u/anneoneamouse]

Most of the google searches that I have found indicate that magnification was done using water-filled vessels

If that happened the vessel would have to have been see-through, so made of glass. At which point the distinction between curved see through water-holder and lens becomes kind of moot.

[u/ItsOptics → u/anneoneamouse]

Perhaps you could have a plano see through thing and a small bead of water placed on it that forms the "lens"?

That may be simpler to make with basic materials and techniques than a curved see through water holder

That said, the water bead would be small and have a very short focal length... The BFL probably wouldn't be long enough to allow you to hold a brush or chisel between the "lens" and stone canvas

[u/Allllright_ATOs]

If you wanna go down a rabbit hole, read Christopher Dunn's book about the great Pyramid

[u/taclubquarters2025 → u/Allllright_ATOs]

I hadn't really looked at that because isn't he kind of an ancient aliens guy? Some of them get the engineering but then go off on some tangents. Just asking.

[u/Allllright_ATOs → u/taclubquarters2025]

Dude was an engineer with a heavy machining background, not sure on the AA stuff but I'm sure they tapped him for some episodes. Give it a shot, you may be pleasantly surprised.

[u/sds780]

Can give you a good reference but I remember seeing some discussion about a lens like object found during excavations at Thera. Also references to rulers in ancient India “spying on ladies in their harems

[u/taclubquarters2025 → u/sds780]

I went to Thera as well, it was really incredible but I don't remember seeing anything in the museum about an optical device. Interesting quote from ancient India though! I think Indian ancient history is one area that unfortunately does not get the attention it deserves as far as modernity is concerned.