More Than an Engima

Yesterday, the physics teacher in my section and I were talking about the different experiences we had in high school regarding math ad physics. He was allowed to use electronic calculators. I, on the other hand, could only use a slide-rule and an Addiator. He hadn’t heard of the slide-rule, so I did a quick Internet search and showed him how to use the thing, and explained why it worked. I also explained the Addiator to him. The cool thing, though, is I found some other nifty sites while we were talking about the history of calculating machines and also cryptographic machines. For your amusement, check out the following.

Derek’s Virtual Slide Rule Gallery

  • This site has simulators for seven different slide rules, a couple of which are specialist rules. The site also has instructions on how to use the rules.

Abacus Simulator

  • Since I’m in China, I’d be remiss to not include this one. The simulator allows you to choose the number of rods, from 11 to 21. Sadly, it doesn’t let you move the upper bead at the same time as the lower beads. I chose this site because it is for the Japanese abacus which is more efficient than the Chinese abacus.

Napier’s Bones Simulator

  • Wikipedia tells me this is good for multiplication, division, and extracting square roots. The article gives detailed instructions on how to use the bones.

Enigma Simulator

  • And, finally, the one that I played with far too long last night. This one really goes into detail on how to use the famous Enigma machine.

I’m definitely going to be using the Engima macine the next time I make an escape room. What I’d like to do here, though, is make a thread game for the Enigma simulator, but that thing takes you into the trillions of possibilities. If you have any suggestions on how, I’m all eyes.

Anyway, enjoy your simulating!

And here is another slide rule simulator, much more fun and robust than the one above.

We weren’t allowed to use calculators or any other calculation aids in my high school physics classes. This was in the mid 1980s. We even had to calculate square roots by hand. We also couldn’t use any notes so I often had to derive formulas during an exam because I couldn’t remember all of them. Though I did well enough in the classes this experience definitely put me off of any interest in studying physics or the sciences.

I graduated high school in 1984. I took both the regular physics class and an advanced AP course. The teacher at the time insisted we obtain and use slide rules, which even forty years ago were difficult to find. (My brother had been through the same teacher’s class, so I got my slide rule from him but others really had to hunt around in stores for them.) As I remember, the reason the teacher insisted on the slide rules was that using them required one to learn to read scales, which is or was important for using various scientific instruments. Also, as I remember, it was possible to mislay the decimal point when reading a slide rule so you had to recognize if the result should be 1014.56 or 101.456.

I still teach my high school students to use a slide rule. Not because the tool itself is practical as a tool any more, but because it’s great for illustrating the properties of logarithms, limited precision, and a number of other important math concepts.

And if anyone ever finds an online virtual slide rule that works right with a touchscreen, let me know.

So do you provide the slide rules for your students? And I think, yes, logarithms and precision may have been part of the reason we were using slide rules forty years ago in high school physics.

Edited to add, I just checked Amazon and even there, actual slide rules were not easily available.

I have enough in my collection for one for each table.

I keep meaning to get around to making a full class set on the laser cutter.

Oh, and I’m not really sure what this has to do with games. Moving to MPSIMS.

For those into this stuff, this is a decent primer:

Hard to believe the first efforts at a 4-banger calculator date from the early 1600s ~= 400 years ago.

Once I’d heard of them I’ve always lusted after a Curta. Have never seen, much less touched, one for real and have no earthly use for one, but dayum!

So have I. The prices aern’t exactly stratospheric; I could conceivably buy one on the collector market. I can’t remember for sure, but I think I saw one at the Computer History Museum.

I was about to post about those. And I remember exactly how and when I heard about them. I had managed to snag a galley print review copy of William Gibson’s newest book Pattern Recognition a couple of weeks before publication. Early in there was a passage where a woman was restlessly walking the London streets late at night:

Summary

She’s in a street of what she thinks are called mews houses, little places, scarily cute, still headed toward Portobello and the market, when she sees them: three men, variously jacketed, their collars up, staring gravely into the open trunk of a small and uncharacteristically old mirror-world car. Not so much a mirror-world car as an English car, as no equivalent exists, on Cayce’s side of the Atlantic, to mirror. Vauxhall Wyvern, she thinks, with her compulsive memory for brand names, though she doubts that this is one of those, whatever those might have been. As to why she notices them now, these three, she later will be unable to say.
No one else in the street, and there is something in the gravity they bring to their study of whatever it is they are looking down at. Careful poker masks. The largest, though not the tallest, a black man with a shaven head, is zipped like a sausage into something shiny, black, and only approximately leatherlike. Beside him is a taller, gray-faced man, hunched within the greasy folds of an ancient Barbour waterproof, its waxed cotton gone the sheen and shade of day-old horse dung. The third, younger, is close-cropped and blond, in baggy black skater shorts and a frayed jean jacket. He wears something like a mailman’s pouch, slung across his chest. Shorts, she thinks, drawing abreast of this trio, are somehow always wrong in London.
She can’t resist glancing into the trunk.
Grenades.
Black, compact, cylindrical. Six of them, laid out on an old gray sweater amid a jumble of brown cardboard cartons.
“Miss?” The one in shorts.
“Hello?” The gray-faced man, sharply, impatient.
She tells herself to run, but can’t.
“Yes?”
“The Curtas.” The blond one, stepping closer.
“It isn’t her, you idiot. She’s not bloody coming.” The gray one again, with mounting irritation.
The blond one blinks. “You haven’t come about the Curtas?”
“The what?”
“The calculators.”
She can’t resist, then, and steps closer to the car, to see. “What are they?”
“Calculators.” The tight plastic of the black man’s jacket creaking as he bends to pick up one of the grenades. Turning to hand it to her. And then she is holding it: heavy, dense, knurled for gripping. Tabs or flanges that look as though meant to move in these slots. Small round windows showing white numbers. At the top something that looks like the crank on a pepper mill, as executed by a small-arms manufacturer.
“I don’t understand,” she says, and imagines she’ll wake, just then, in Damien’s bed, because it’s all gone that dreamlike now. Automatically seeking a trademark, she turns the thing over. And sees that it is made in Liechtenstein.
Liechtenstein?
“What is it?”
“It is a precision instrument,” the black man says, “performing calculations mechanically, employing neither electricity nor electronic components. The sensation of its operation is best likened to that of winding a fine thirty-five-millimeter camera. It is the smallest mechanical calculating machine ever constructed.” Voice deep and mellifluous. “It is the invention of Curt Herzstark, an Austrian, who developed it while a prisoner in Buchenwald. The camp authorities actually encouraged his work, you see. ‘Intelligence slave,’ his title there. They wished his calculator to be given to the Führer, at the end of the war. But Buchenwald was liberated in 1945 by the Americans. Herzstark had survived.” He gently takes the thing from her. Enormous hands. “He had his drawings.” Large fingers moving surely, gently, clicking the black tabs into a different configuration. He grasps the knurled cylinder in his left, gives the handle at the top a twirl. Smoothly ratcheting a sum from its interior. He raises it to see the resulting figure in a tiny window. “Eight hundred pounds. Excellent condition.” Dropping an eyelid partially, to wait for her response.
“It’s beautiful,” his offer finally giving her a context for this baffling exchange: These men are dealers, come here to do business in these things. “But I wouldn’t know what to do with it.”

Your stratosphere must be higher than my stratosphere.

That’s a little higher than last time I checked, but not ridiculously so.

If I had the means and the space, I think it would be interesting to collect old scientifc and medical devices. I’d love to have a nice sextant, for example.

Agreed. Not going to get a dozen as gifts, but as a one-off collection item, sure.


You can buy a real, new, albeit not very exciting, fully functional sextant for pretty cheap:

One that looks like the classic brass instrument in a wooden box is rather pricier:

Both shoot stars just fine.

Here is a curta emulator.

I’ve used one like that before. I was off by about 20 miles; I attribute that to operator error rather than any flaw with the instrument.

As a collectible, I’d get one that was a proper antique, but also functional.

A friend of mine has a Curta. A few weeks ago our families spent a weekend together and I played with his Curta for a couple of hours. I’ve wanted one for a long time, but after having that extended time with it, I finally convinced myself that I wouldn’t really find it engaging for more than a few days.

The mention of logarithms reminds me of another tool that was used back in the days before electronic calculators became ubiquitous, namely logarithm tables. Anyone remember those little booklets with page after page of logarithms? They had numerous uses but the most common one from a calculation perspective was to turn the multiplication or division of big numbers into a much simpler problem of addition and subtraction.

Yes. And the daunting task of memorizing some of it. That’s not something I miss.

This thread was apparently originally about some game, or I would have mentioned those myself. I have seen and touched those and they are as sweet as you think they are, a pleasure to use. I vaguely remember hearing something about them getting some use during scientific expeditions to remote places in the 1970s or 1980s where extreme conditions in the rainforest or jungle or whatever would supposedly have done in an electronic calculator.

There is no logarithm button on a mechanical (at least a Curta-type) calculator, let’s put it that way. Addition and subtraction is all they do.