Tag Archive for 'History'

Lieutenant Brenske’s Marsch-Zirkel

In the days before GPS, Google Maps and Waze, people used maps; and to figure how long it would take to get from A to B on a map, you could make excellent use of a Marsch-Zirkel, or march compasses… like the lovely device described in this new article on my History of Computing exhibition.

Lieutenant Brenske's Marsch-Zirkel

Dating back to the late 19th century, this ingenious little tool helps you figure the distance and the time to cover it – with infantry or cavalry.

Take a look!

A most unusual slide rule

The Baines slide rule is one of the most unusual ones in my collection, because of the metal contraption on its back that moves all its parts in unison. Here it is:

The Baines hydrological slide rule

This slide rule was designed by a British civil engineer from the Punjab; it is used to calculate water flows and pressure drops in cast iron water pipes.

You can see the full details, and a sample calculation demonstrating the device’s function, in this new article on my history of computing site.



The ancients had it right

These days the preference for shoddy, cheap, use-and-discard products is all over the place. Here is an example:

Street sign

This sorry street sign in Jerusalem has taken on a very “artistic” look – because it is made from a blue layer of stick-on plastic sheet over a metal plate. Over time the plastic started to shrink and curl, with this amusing result.

And it occurs to me that the ancients who lived in our city had a better method. Take this stone, which was part of the temple enclosure parapet in the second temple period (around the time of Christ). It too carries a Hebrew inscription, identifying the location of “the house of trumpeting” – the location where the priest stood who blew the ram horn to announce the entry of the Sabbath.

The house of trumpeting inscription, Temple mount, Jerusalem

This stone took a big fall when the Romans destroyed the temple, but the lettering on it is crisp and legible after two millennia.



Cornell’s Calculator in a Book

Some of the most fascinating items in my History of Computing collection are the one-of-a-kind, undocumented ones. The latest such addition to the collection is a calculator hidden in a book-like case, that has no mention anywhere that I could find.

This is Charles Cornell’s F.24 aerial photography planning calculator, and you can read all about it in my latest article. Enjoy!

Cornell's F.24 Aerial Photography calculator

A beautiful instrument

This Barometer was made in Florence some 100 years ago, and served my late grandfather, first in Italy, then in Israel; it ended up on my wall, a family heirloom to delight the heart of any engineer.


It is a large (23 cm across) Aneroid Barometer, an instrument to measure atmospheric pressure by means of the compression of an evacuated metal capsule (the silvery part with concentric corrugations). Back in the day you would set the golden arrow to cover the black one in the evening, and when leaving home in the morning you’d tap the glass to see which way the black arrow would slightly move from under it – denoting whether the pressure is rising or falling, i.e. whether the weather was getting sunnier or rainier.

What makes this instrument so lovely is the inside mechanism, which is made of springs, hinges, rods and chains that convey the movement to the pointer – and these are made of many beautifully burnished alloys of brass and steel, as you can see below (click either photo to enlarge it).

Barometer mechanism

The say some modern smartphones include a barometric sensor… but they can’t hold a candle to my grandpa’s barometer when it comes to sheer elegance and beauty!

Form and Materials: swords of yesteryear

Form follows function; but often both must follow the available materials.

Consider the image that comes to mind at a statement like

The great king raised his mighty sword to smite his enemies.

Surely, you imagine a sword structured something like this:


Photo courtesy Søren Niedziella, shared on flickr under CC license.

This, after all, is just about what a proper King’s sword would have to look like to serve him well.


Well, how about this instead?

Khopesh sword

Photo courtesy Dbachmann, shared on Wikimedia Commons under CC license.

Would you recognize this as a sword? If you were an Egyptian or Mesopotamian soldier some 4000 years ago, you certainly would. In fact, this was what a standard battle sword looked like between 2000 and 1300 BC. This one, missing its hilt at the right end, is from 1750 BC.

These weapons were in use across the ancient near east, and were called Khopesh in Egyptian. Their only sharpened edge was the outer side of the curved part at the left. You used this edge to beat on people, much like you’d use a club; stabbing was not even an option.

So, what’s going on here? A sword should be long, thin, sharp and pointy, so you can stick it into people at arm’s length; why make one that looks like a short, thick, bent metal rod that can only be used to clobber your enemies?

This is where a key fact comes in: we’re talking Bronze Age, when iron (and much less steel) was unavailable. Weapon designers were constrained by a metal that was too soft for anything long and thin; nor would it stay sharp for long. A one-sided “sickle sword” like the Khopesh could have a thick backside that would give the bronze both durability and hitting momentum.

Over the years the design varied somewhat; notably the sharp part grew longer at the expense of the handle, as in the sword below:

Khopesh sword

Incidentally, I wasn’t kidding about the king: below you see a PR image of Ramesses III smiting his enemies with a curved sword just like this one. He grabs the smaller-than-life enemies by the hair and is ready to smite them with the sword’s edge (the kings of those days, unlike today’s ornamental ones, were pretty hands-on where smiting was concerned). In fact, this image makes sense of the fact that “smite” is defined in the dictionary as “to strike with a heavy blow or blows” – strike, not skewer as with later sword designs. The guy on the right is more than a king – he is the Akkadian God Nergal, no less, and he holds a sickle sword in his left hand, its blade resting on the ground.

Ramesses III and Nergal

But then came the iron age, and it became possible to craft sharp long blades that wouldn’t break; and the bronze Khopesh went the way of the flint axe, doomed by a new technology that enabled new forms and new functionality.

That’s Progress for you…

A curious slide rule design

For some reason, inventors in the first half of the 20th century thought that incorporating a slide rule into a mechanical pencil was a great idea. In reality, these combination devices were of dubious utility, gives their low precision as calculators… but they are certainly ingeniously designed.

Pencil Sliderules

I describe three of them,  including one extremely rare device, in a new article on my history of computing site.


My Dad’s tin suitcase

My father, God rest his soul, was a young physics student when Israel’s war of independence broke out, and he was among the defenders of the Jewish Quarter in Jerusalem’s Old City. When the quarter fell to the superior forces of the Jordanian Legion, he was taken prisoner and spent 9 months in a POW camp near Mafraq in Transjordan.

When he came back he brought with him a humble but interesting artifact: a small suitcase, about the size of a modern carry-on, made entirely of tinplate. This survived to this day, and has an interesting story to tell.

Tinplate suitcase from POW camp

My father, it turns out, had ample time on his hands in that camp, and he devoted it to studying Physics (he was to become a Physics professor for the rest of his life) and to teaching it to any of the other prisoners who found it preferable to doing nothing. In return, one unnamed prisoner used his skill as a tinsmith to produce this suitcase for my Dad.

The source of the material is obvious if you turn the thing over:

Tinplate suitcase from POW camp

This was a standard tin of biscuits, provided to the camp’s residents either by the Jordanians or by some welfare organization. They must’ve been rather stale, as they date to 1945, but in war you aren’t choosy; meanwhile the empty tin was recycled into this suitcase.

The craftsmanship and attention to detail in this item is wonderful indeed, considering the difficult conditions of its manufacture. The potentially sharp edges are all doubled up for safety and convenience. There is a folding handle, hinges, even a hasp – and everything is made from tinplate and steel wire. Here are some photos of the details:

Tinplate suitcase from POW camp

Tinplate suitcase from POW camp

Tinplate suitcase from POW camp

Good job, unknown tinker!


Independence Day pins: a case study in deteriorating design

Unlike the US, Israel doesn’t celebrate its Independence Day by sending its president to fight invading aliens in huge spaceships (our presidents are too advanced in years for that). We do, however, have other traditions, and one of the earliest of these has been for the Jewish National Fund to issue each year a small lapel pin celebrating the young state’s birthday. Since my childhood these would be sold for a small donation to the JNF’s activity, and I’ve kept some of them and bought some others later, making a nice little collection.

Here they are. Each row stands for one decade; the oldest pin I have, with the stylized number eight, is from 1956; the newest, #40, is from 1988.

Israeli independence day lapel pins                                        Click photo to enlarge

And as I look at the series, I’m amazed to see that while the state of Israel has progressed from humble and austere beginnings to become today’s vibrant “start-up nation”, these pins have moved in the opposite direction: their design and quality of manufacture have degenerated considerably with the advancing years!

Like this:

Israeli independence day lapel pins

This photo shows the pins from years 20, 25 and 38. See what I mean? The leftmost pin is cast in a solid bronze alloy; all the years before it use embossed metal too. But year 25 uses a flat metal disk with a paper sticker, as do subsequent years (and years 31 and 37 shamelessly recycle the same design on the paper!); then, in year 38, we see a move to the el-cheapo buttons used for political rallies and countless other mundane uses.

And it gets worse. Year 39 had three versions: the cheap button, a flimsy plastic “paperclip”, and a disposable paper sticker!

Israeli independence day lapel pins

Incidentally, year 10 also had a choice; but not between flimsy and disposable. In that year there were two respectable, embossed metal pins – one in tinplate and one in bronze.

Israeli independence day lapel pins

Consider the change in raw materials in this sequence:

Israeli independence day lapel pins

Bronze in year 10 (this was the only material in use in the first decade), tinplate in year 16, and the yucky plastic in year 39.

Lastly, consider the complexity of structure in the year 14 pin from 1962 (the wooden backplane was meant to celebrate the JNF’s highly successful reforestation efforts), in contrast to the trivial technique in the paper sticker from 1987.

Israeli independence day lapel pins

Of course, we see this decline of craftsmanship in many manufactured goods in our modern world – and here it is captured nicely in a microcosm of ID lapel pins!

Cherubs and Technology

I wrote recently about the batch of WW1 postcards left by my great-uncle Ettore… and while the cards described in that article focus on hate propaganda, there was also one postcard  that is quite endearing, and here it is:

A WW1 postcard of the Italian Signal Corps

This postcard was issued 100 years ago by the Third Regiment of Telegraph Operators – basically, a unit of the Signal Corps of the Royal Italian Army. Click it to get a closer look!

The endearing scene shows some classic Italian city (looks like Florence), a bunch of cute cherubs using a very early telephone, a war goddess (?),  and various electrical gear – antennas, telegraph lines, and unidentified apparatus that no doubt would be familiar to Guglielmo Marconi.

Those ancient telegraphers were really proud of their trade; they could see how wonderful, how outright angelic, the ability to talk at a distance was. Today we have instant connectivity, anytime, anywhere… but that early innocent sense of wonder is gone, and I can’t think of one internet provider that uses angels in their advertising.

Those were the days…