# Rulers Of The Ancient World — Literally!

If you were expecting a post about ancient kings and queens, you are probably at the wrong website. [Burn Heart] has a fascination with ancient measuring devices and set out to recreate period-correct rules, although using decidedly modern techniques.

The first example is a French rule for measuring the “pied du Roi” or king’s foot. Apparently, his royal highness had large feet as a the French variant is nearly 13 inches long. The next rulers hail from Egypt and measure cubits and spans. Turns out the pyramid builders left a lot of information about measurements and their understanding of math and tools like dividers.

Other rules from Rome, Japan, and the Indus Valley are also included. According to the post, one set of these rulers used locally sourced wood, but a second “limited” edition used wood that the originals might have. Most of the rulers were etched via CNC, although the French ruler was hand-etched.

The Romans, apparently, had smaller feet than French royalty, as their Pes or foot was about 11.65 inches. There are plenty of little tidbits in the post ranging from the origin of the word inch to why the black wood used for piano keys is called ebony.

We’ll stipulate this isn’t exactly a hack, although it is fine workmanship and part of hacker culture is obsessing over measuring things, so we thought it was fair game. These days, rulers are often electronic. Which makes it natural to put them on a PC board.

## 29 thoughts on “Rulers Of The Ancient World — Literally!”

1. Bob says:

The metre should have been made equal to the yard. Close enough for government work and would have saved a lot of hassle.

1. bob says:

the metre length wasn’t a random choice though. I saw a video that stated water droplets on a flat surface have a consistent size of 1cm. This was chosen as a basis for length. I don’t understand it because i would think the volume of water in a droplet could change.

1. K says:

… and it is flatout wrong. The meter was (initially) defined to be a millionth of the earth-quadrant.
The 1cm diameter of a droplet must be purely coincidental.
On the other hand, I’m not sure if I’m missing a joke – the inch seems to have its roots in the size of grains.

2. Markus says:

Indeed, the metre length was not a random choice, however, it was defined as the 1/10’000’000 part of the quadrant of the earth in the last decade of the 18th century (see wiki). Today the metre is defined in a completely different way: by the second (s) and the speed of light c in vacuum.
Can you please provide us with a link to the video with the water droplets? Thanks.

1. Dude says:

And that was a consequence of the French deciding to use 400 degrees in a circle instead of 360 for surveying purposes. If they hadn’t, the quadrant would have been 90 degrees instead of 100 and the meter would probably have been defined very differently.

For instance, a minute of an arc is roughly 1.85 kilometers or the “geographical mile”, and a second of an arc is 31 meters, and a third of an arc is 51 centimeters, variable depending on which quadrant of the earth you measure because it isn’t a perfect sphere. A third of an arc is hard to measure, so they could have given up at the second of an arc and divided by ten from that, getting the standard “metre” down to about 30.8 cm which is very close to the modern foot had they chosen to do so – for compatibility with the rest of the world at that time.

But the French had to be different.

1. Bob says:

Wasn’t for surveying, it was for navigation. One degree of travel = 100km.

2. Dude says:

>One degree of travel = 100km.

What does that matter before kilometers were even defined? If the circle was divided by 360 then one degree could still be 100 units – the unit would just be slightly different in real length.

3. Dude says:

For navigation purposes, 360 degrees makes more sense because it’s divisible by both 24 and 60. Reason being that local time was used to figure out your location.

One minute difference in time in a sun dial or other celestial observation is roughly 28 kilometers east or west. Divide by ten a couple times and you get to 28 cm – or roughly a foot again.

4. Bob says:

Gradians & kilometres came about at the same time, they’re metric degrees.

And of course time was metric as well, so 360 degrees = 24H was irrelevant.

5. Kindltot says:

360 was based on Babylonian math which was a numbering system based on 12, with a “hundred” as 60 (it was written as a large dot) Duo-decimal systems (counting by dozens) are handy since most numbers besides the primes are divisible, and the system lets you do a quick addition on the joints of your fingers, and fingers, to allow a quick computation.

The Babylonians also had a large science in astrology that created quite a literature in astronomic measurements and calculations, which were picked up by the Greeks, and from them the Romans, and on down to today where we have a 12-24 hour and clock and grosses and egg cartons, and we get to fight over the benefits between radians and degrees.

2. Hirudinea says:

Well the metre was supposed to be what you said, but after they had sent out all the reference metres to every town in France they found that the original calculations were wrong, but since it would have to expensive to correct it they said “F it” and went with the mistake.

1. Bob says:

Plus the equator is bigger than the North/South measurement they did, so that’d upset things a tiny bit.

Like I said, just hijack the yard & call it a day. 3 feet / 36 inches / 100 cm, all the same. Everyone happy.

2. Kindltot says:

Thomas Jefferson proposed a modification to decimalize the standard foot/yard/mile by a “metric foot”. Before him, Christopher Wren, who rebuilt a lot of London after the London fire did his architectural drawings for the construction crews in “Metric yards” that are almost identical to the modern Meter

I love the idea, but then I went through a course of timber surveying and that industry also uses a foot divided by ten increments

3. Bob says:

Yep, decimal feet have been a thing in construction for a long time. Like the decimal inch in printing, which is how we wound up with the 2.54mm PCB spacing.

3. Bob says:

Of all the pseudoscience bollocks in the world, that’s quite possibly the dumbest. It was dumb when it came up years ago, and it hasn’t gotten any better.

1. BT says:

But it’s in a youtube video, it must be true.

1. Bob says:

Is that the video where he drips water onto a rock, ignores that they all come out different sizes and then measures the 10mm one?

2. Sword says:

Yep I actually went “Wait what? No.”

2. Peter says:

Americans doing everything to just not go metric.

2. rthrehrth says:

Question is what rulers use in mars? Elon use meter not inch?
This is questions

I dream about small set of size bolts and nuts.
So that the entire rocket can be repaired using a minimum of tools

3. paulvdh says:

“Most of the rulers were etched via CNC”

That’s weird. I did not know they had CNC machines back then.

1. macsimski says:

of course they had them, but they were human CNC’s like the human computers from the time.

4. Hirudinea says:

I need that cubit ruler, I’m thinking of building a boat… I’ve said too much.

5. HaHa says:

Nobody posting that ‘old what’s his name’ wasn’t actually _that_ short.

The frogs just had long feet, also possibly why stubby endorsed metric.

6. The Commenter Formerly Known As Ren says:

As an old (woodworking) tool enthusiast, I’ve been reading that rulers from around 100 years ago do not have a standardized “inch”.
My point being, it’s not so far in the past.

7. shod says:

There’s some odd things with those sizes of the past, like those Roman feet, I thought Romans were small compared to modern man so isn’t even that mentioned size a bit odd?
Same for cubits, I once read about the length of the ‘biblical’ times cubit (length of forearm based) on wikipedia and it was insanely long compared to modern arms.
So what gives? Were people 2000 years ago like dinosaurs, insanely large? Or did they look very gorilla-like with huge feet and extra long arms. But then why do their statues no reflect that huh.
Maybe the statues are like fashion magazines and they paint an unachivable image, driving those Roman teenage girls crazy :)

1. Bob says:

Cubit was elbow to fingertip, not just the forearm. Well, usually.

Or 2 spans (pinky tip to thumb tip).

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.