The Antikythera mechanism – 254:19 ratio
leancrew.com
leancrew.com
I am not sure this is entirely accurate. According to Wikipedia:
> The notion that the Earth revolves around the Sun had been proposed as early as the 3rd century BC by Aristarchus of Samos,[1] who had been influenced by a concept presented by Philolaus of Croton (c. 470 – 385 BC). In the 5th century BC the Greek philosophers Philolaus and Hicetas had the thought on different occasions that the Earth was spherical and revolving around a "mystical" central fire, and that this fire regulated the universe.[2] In medieval Europe, however, Aristarchus' heliocentrism attracted little attention—possibly because of the loss of scientific works of the Hellenistic period.[b]
Source: https://en.m.wikipedia.org/wiki/Heliocentrism
Contrary to the recent revisionist version of the “dark ages”, they were pretty dark if you were a Greek of the Hellenistic period, an Athenian 5th century BC or a Roman the next 500-800 years. Loss of philosophical (locked in monasteries) and technical knowledge is common and Heliocentrism or the blood circulation system (Egyptians during the Ptolemy era had knowledge comparable to the one we will acquire again 18th century) are two prime examples.
But nobody would characterize the history of the science that way, because it simply isn't true. "Wasn't known to the Greeks" is inaccurate, particularly in its historical context, since science and philosophy were often "little more than 'this idea some guy had.'"
Because it was pretty common scientific knowledge that earth was round back then. A knowledge that got lost during the dark ages.
For example: In the third century BCE , Eratosthenes, a Greek librarian in Alexandria , Egypt , determined the earth's circumference to be 40,250 to 45,900 kilometers (25,000 to 28,500 miles) by comparing the Sun's relative position at two different locations on the earth's surface.
Any examples of that? I've heard it called a myth.
The geo-centric model assumed the earth was spherical but it didn't rotate or otherwise move.
Citation needed, especially given the “comparable”.
The “dark age’s revisionism” afaik doesn’t claim that there was no loss of technical and philosophical knowledge (not that the average roman soldier would normally be a philosopher…), but that it’s limited to a few centuries. By the 12th and 13th century it’s very difficult to speak of dark ages.
I just asked chatgpt “Based on what you know about me, what do you think I would be interested in seeing in Athens?”
The Herakleidon Museum was third on the list. May have to try this again in the future.
Annoyingly I’m in Athens right now but flying back tomorrow way too early to sneak a visit in :(
This phrasing oversells it a bit too much: The water wasn't a power source and there was no long distance movement of it.
They signaled between users with the light of a burning handheld torch, and the duration of the light corresponded to predefined messages.
Water was used at each end for independent stopwatches, to measure the duration of the light. It's easy to imagine an equivalent system using sand hourglasses.
https://en.m.wikipedia.org/wiki/Hydraulic_telegraph#Greek_hy...
https://youtube.com/playlist?list=PLZioPDnFPNsHnyxfygxA0to4R...
Up to date and with a very good discussion of the 254:19 gearing.
Also much more detail on the history of the mechanism.
On the other hand, you published it during a full moon. That's at least slightly appropriate given the subject matter :)
WOW.
Also, Elgin marbles need to be returned. Parthenon is defaced by their absence.
As I'm not a machinist, I'm not going to try to explain just where in the geartrain you'd use this pair to convert your metric machine lathe into a US customary lathe, but that's what they're for.
The 2.54 ratio lets you turn metric threads on a US machine, with the help of tables in the manual for how to set all of the levers. Machinists hate it, and these days will prefer to buy a die for the occasional threading job.
It's not immediately obvious to me (not a machinist) that the 127/50 ratio gets you the ability to cut metric threads without a mess of other head-scratching because you're now dealing with period instead of frequency.
The lathe that I use hasn't had its threading gears installed in ages.
A weird historical tidbit is that after WWII a couple of standards emerged for bicycle parts in Europe, where they used metric diameters and inch thread pitches.
Also, left handed threads involve their own issues since the spindle chuck wants to unscrew itself.