The Mysterious Roman Dodecahedron Was Possibly Just For Knitting

Over the years archaeological digs of Roman sites have uncovered many of these strange dodecahedrons, usually made out of metal and with various holes in their faces. With no surviving records that describe how they were used, speculation has ranged from jewelry to a knitting aid. In a 2023 video by [Amy Gaines] it is this latter use which is explored, using a 3D printed dodecahedron and some wooden dowels to knit both gold wire and yarn into rather intricate patterns that are also referred to as ‘Viking Knitting’.

As we mentioned previously when yet another one of these dodecahedrons was uncovered, their use was unlikely to be of supreme relevance in military or scientific circles on account of a lack of evidence. What is quite possible is that these were both attractive shapes for jewelry (beads), and useful knitting aids for both jewelry makers (for e.g. gold wire braiding) and quite possibly yarn-related uses. The results which [Amy] demonstrates in the video for the gold wire in particular bear a striking resemblance to ancient braided gold chains on display at the Met and other museums, which leads credence to this theory.

If these items were effectively just common knitting tools, that would explain why the historical record is mum on them, as they would have been as notable as a hammer or a precision lathe used by the ancient Greeks.

Thanks to [john] for the tip.

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The NSA Is Defeated By A 1950s Tape Recorder. Can You Help Them?

One of the towering figures in the evolution of computer science was Grace Hopper, an American mathematician, academic, and Naval reservist, whose work gave us the first programming languages, compilers, and much more. Sadly she passed away in 1992, so her wisdom hasn’t directly informed the Internet Age in the manner of some of her surviving contemporaries.

During her life she gave many lectures though, and as [Michael Ravnitzky] discovered, one of them was recorded on video tape and resides in the archives of America’s National Security Agency. With the title “Future Possibilities: Data, Hardware, Software, and People”, it was the subject of a Freedom Of Information request. This in turn was denied, on the grounds that “Without being able to view the tapes, NSA has no way to verify their responsiveness”. In short, the recording lies on Ampex 1″ reel-to-reel video tape, which the NSA claims no longer to be able to read.

It’s fairly obvious from that response that the agency has no desire to oblige, and we’d be very surprised to find that they keep a working Ampex video system to hand on the off-chance that a passing researcher might ask for an archive tape. But at the same time it’s also obvious that a lecture from Rear Admiral Hopper is an artifact of international importance that should be preserved and available for study. It’s an interesting thought exercise to guess how many phone calls Hackaday would have to make to secure access to a working Ampex video recorder, and since we think for us that number would be surprisingly low it’s likely the NSA know exactly who to call if they needed that tape viewed in a hurry. We don’t have influence over secretive government agencies, but if we did we’d be calling shame on them at this point.

If you’re curious about Grace Hopper, we’ve talked about her work here in the past.

Thanks [F4GRX] for the tip.

Ampex image: Telecineguy., Public domain.

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.

Dad? Where Did Printed Circuit Boards Come From?

These days, it is hard to imagine electronics without printed circuit boards. They are literally in everything. While making PCBs at home used to be a chore, these days, you design on a computer, click a button, and they show up in the mail. But if you go back far enough, there were no PC boards. Where did they come from? That’s the question posed by [Steven Leibson] who did some investigating into the topic.

There were many false starts at building things like PCBs using wires glued to substrates or conductive inks.  However, it wasn’t until World War II that mass production of PC boards became common. In particular, they were the perfect solution for proximity fuzes in artillery shells.

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A Look Back At The USSR’s Mi-6 Helicopter Airliner

Most of us would equate commercial airline travel with fixed-wing aircraft, but civilian transport by helicopter, especially in large and sparsely populated regions, is common enough. It was once even big business in the Soviet Union, where the Aeroflot airline operated passenger helicopters in regular service for many decades. In the mid-1960s they even started work on converting the Mil Mi-6 — the USSR’s largest and fastest helicopter — to carry paying passengers. Unfortunately this never got past a single prototype, with the circumstances described by [Oliver Parken] in a recent article.

This passenger version of the Mi-6 got the designation Mi-6P (for passazhirskyi, meaning passenger) and would have seated up to 80 (3 + 2 row configuration), compared to the Mi-8 passenger variant that carried 28 – 31 passengers. Why exactly the Mi-6P never got past the prototype stage is unknown, but its successor in the form of the Mi-26P has a listed passenger variant and features. Both have a cruising speed of around 250 km/h, with a top of 300 km/h. The auxiliary winglets of the Mi-6 provided additional lift during flight, and the weight lifting record set by the Mi-6 was only broken by the Mi-26 in 1982.

An obvious disadvantage of passenger helicopters is that they are more complicated to operate and maintain, while small fixed wing airliners like the ATR 72 (introduced in 1988) can carry about as many passengers, requires just a strip of tarmac to land and take off from, travel about twice as fast as an Mi-6P would, and do not require two helicopter pilots to fly them. Unless the ability to hover and land or take-off vertically are required, this pretty much explains why passenger helicopters are such a niche application. Not that the Mi-6P doesn’t have that certain je ne sais quoi to it, mind.

Access To Fresh And Potable Water: An Ancient And Very Current Challenge

Throughout history, clean and potable water has been one of the most prized possessions, without which no human civilization could have ever sustained itself. Not only is water crucial for drinking and food preparation, but also for agriculture, cleaning and the production of countless materials, chemicals and much more. And this isn’t a modern problem: good water supplies and the most successful ancient cultures go hand in hand.

For instance, the retention and management of fresh water in reservoirs played a major role in the Khmer Empire, with many of its reservoirs (baray) surviving to today. Similarly, the Anuradhapure Kingdom in Ceylon (now Sri Lanka) featured massive reservoirs like Kala Wewa that was constructed in 460 CE with a capacity of 123 million m3. In the New World, the Maya civilization similarly created reservoirs with intricate canals to capture rainwater before the dry season started, as due to the karst landscape wells were not possible.

Keeping this water fresh and free from contaminants and pollution was a major problem for especially the Maya, with a recent perspective by Lisa J. Lucera in PNAS Anthropology suggesting that they used an approach similar to modern day constructed wetlands to keep disease and illness at bay, while earlier discoveries also suggest the use of filtration including the use of zeolite.

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Cleaning Up World War 2’s Legacy On The Seafloor With Robots

Until the 1970s, a very common method to dispose of unneeded munitions was to simply tip them off the side of a ship. This means that everything from grenades to chemical weapons have been languishing in large quantities around Europe’s shorelines, right alongside other types of unexploded ordnance (UXO).

Although clearing and mapping such dump sites are a standard part of e.g. marine infrastructure such as undersea cabling and off-shore wind turbines, no large-scale effort has so far been undertaken to remove them, even as they continue to pose an increasing hazard to people and the environment. Most recently, efforts are underway to truly begin clearing these UXO, as the BBC reports.

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