The iPhone of Slide Rules - Numberphile

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Alex Bellos discusses slide rules and then the Halden Calculex, which he describes as the "iPhone of Slide Rules"
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[@stevepaulsson8266]

Old joke: the definition of an engineer is someone who when asked what 2x2 is, whips out his slide-rule and says "3,9"

[@dochatteras]

+Steve Paulsson Yes. And yet, the Boeing 747 was designed solely using the slide rule. With training and practice (like all things) it's amazing how effective they could be.

[@SorakaOTP462]

+Steve Paulsson Not 3.9, more like 3.99998.

[@idlingdove]

+Steve Paulsson The joke I heard when I was young went as follows:Definition of an old-time engineer: ask him what 2x2 is, he whips out his slide rule from his back pocket, and says "about 4". Definition of a modern engineer: ask him what 2x2 is, he whips out his calculator from his shirt pocket, and says "4 point zero zero zero". I guess that a natural extension of this for the current generation would be: ask a current engineer what 2x2 is, he looks at you and says, "why don't you Google it?".

[@heimdall1973]

A mathematician will say there is exactly one solution. An accountant will ask what you want the answer to be. There are more but I don't remember them.

[@dontworry1302]

An Engineer will ask How close does it need to be?

[@largesatsuma]

Price 1/6 = 1 shilling and 6 pence. Pre-decimal currency was used in the UK until 1971.

[@davidellis4031]

+Slim Charles Yup - you got there first my friend. I guess I can add that it's technically 7.5p in today's money, but that was from the time when the £500+ that an iPhone costs now would buy you a country mansion.

[@ranged12345]

+Slim Charles Which is around 13 pounds accounting for inflation.

[@mickthomas8983]

+Slim Charles How I learned to remember conversion from 'old money' into 'new' is to remove the slash, and then half the remaining figure. So, 1 / 6 becomes 16, half that is 8 (pence). Not exact, but near enough if you were in a shop in 1971. I love the way it works out in two easy steps. ** Potential joke about LSD (pounds, shilling, pence) producing a warm fuzzy feeling in the early 70s **

[@jesusthroughmary]

+Mick Thomas Actually works out to be 7.5 new pence.

[@mickthomas8983]

+jesusthroughmary Thank you. As I said in my comment, 8 pence was "Not exact, but near enough...". It's just the 'ready-reckoner' method to reach a close approximation. I also used an online converter and got 7.5 new pence.

[@TheHoaxHotel]

I carry one as a concealed weapon. Fast and functional, guaranteed to make an attacker's brain hurt.

[@m-yday]

You know what. That's a magnificent comment

[@jaakkohintsala2597]

+Shvet Maharaj i agree

[@rudyhero1995]

+Shvet Maharaj a significant moment*

[@888SpinR]

+The Hoax Hotel Shame on you, carrying around a weapon of maths instruction like that!

[@Bobdowntheroadshow]

+888SpinR "weapon of maths instruction" give this man a clap.

[@LNC4P]

As a pilot, we use these circular calculators on a regular basis. However, more modern digital calculators are now becoming more prevalent. These aeronautical computers are called E6-B or CR-3 computers. You can also find them on wrist watches as their bezel. Probably the most common company that designs such watches is Citizen but I also have a Pulsar with such bezels. It does come in very handy when you need to do a somewhat complicated calculation on the fly.

[@howardebenstein3204]

On the fly, eh?

[@drenz1523]

nice pun

[@simonmacomber7466]

I remember wandering around to many cities with my dad at some point in the mid 1980s while he desperately looked for a place that sold slide rules. The fact that few employees of any store knew what one was, kept making him angrier and angrier. But not as angry as he got when an older employee pointed out that they had stopped making such things because scientific calculators did the same thing much better. I had been using such a calculator in high school starting in 1984.

[@estebson]

Oh man, I imagine you've gone through the same feeling looking for something from your childhood in modern times or finding people not knowing what you're talking about, ha ha 😅.

[@jakebrodskype]

Most slipstick users know to use the C and D scales for multiplication and division. The A and B scales are squares of the C and D scales, so you lose some precision there.

[@ffggddss]

Yes, because the A&B scales have half the cycle-length. There was often also a K scale, for cubing the C&D scales. One-third the cycle-length, which meant even greater loss of precision. Fred

[@pyropulseIXXI]

I have LL1, A, B, ST, T, S, C, D, DI, k, LL2, DF, CF, Ln, L, CI, C, D, LL3, +e on my 5inch Pickett N600-ES LOG LOG Speed Rule

[@deezynar]

I hear him speaking quietly in the darkness, 'My preciousss!.'

[@leonardomona9376]

7:14 "what do you do with that?" ," i sort of take it out and stroke it, and polish it and put it out it there.And you know, talk to it". LOL

[@thewwefan57]

It's incredible how there is no limit to how useful and practical something can be

[@JoeJoeTater]

Man, ya can't make a video about slide rules without throwing in an explanation of how logarithms make them work.

[@numberphile]

+JoeJoeTater it's been done so many times (as you allude to yourself) that I actually cut it out!

[@Skelpolu]

+Numberphile Okay, point taken - However, could you add an annotation to a video explaining how logarithms make them work?

[@Nilguiri]

+Numberphile Sounds ideal for a cheeky Lagniappe?

[@tomwhiteley4126]

+JoeJoeTater If you look at the first 2 laws of logs, which show that adding logs is the same as multiplying logs, and division is the same as subtraction, then it takes advantage of this fact, if you take a logarithmic scale :)

[@TheRipler]

+Numberphile This needs extras. Also would like to see more about the other scales.

[@silvereaglexi3888]

A nerd's lightsaber is a lightsaber.

[@cicci0salsicci0]

+SilverEagle XI fair enough

[@1rian25]

I think he meant it in comparison to a Jedi.

[@silvereaglexi3888]

Kneedragon1962 i would say the sonic screwdriver is in a separate category, and that you could say the same thing i said in my original comment except replace the word "lightsaber" with the words "sonic screwdriver" and it would still be true.

[@Kneedragon1962]

+SilverEagle XI Conceded.

[@havan56]

+SilverEagle XI yep. I'd say that this is the Steampunk Lightsaber

[@MurcuryEntertainment]

Man I love analogue computing devices. I have no idea how to use most of them, but they're incredible.

[@Mrfailstandstil]

*I DEMAND a review of all of the collection of maths instruments that he has!*

[@dpnast8301]

I demand logarithms and trigonometrics on slide ruler

[@markprange238]

In the background he has a cylinder with a spiral logarithmic scale.

[@L17bligaman]

Totally Agreeable

[@Triantalex]

??

[@richardwakelin843]

I grew up in the 60s, dad was an engineer & draughtsman and we was used to using old school things, i can remember the first readily available casio calculators and digital watches, we had a b&w tv which we had to tune with a dial & sometimes had to move the ariel about to get a reasonable signal. I forgot all about these things until i saw your sliderule. Thanks for the memories. Have a great day 😊

[@jjwarner9419]

But do I have to buy a new one every 3 months?

[@maxnullifidian]

And do you have to camp out in front of the store for 3 days before it's available?

[@RWBHere]

No. They will last a lifetime if cared for properly, and they never need re-installing or upgrading. Mine is over 40 years old and is as accurate as it was when new.

[@kemcolian2001]

@@RWBHere r/woosh

[@dannywhittaker8219]

My dad just gave me his old circular slide rule for my birthday this year, pretty cool stuff!

[@stocktonjoans]

"Mother, I have the knowing of the sliding rule! I can tell the sine what to do, and the cosine likewise and work out the tangent of t'quadratics" Terry Pratchett RIP

[@clockworkkirlia7475]

Yes! Haha, that's exactly what I was thinking of. I didn't realise how calculation-assisting the actual thing was... As ever, GNU Terry Pratchett

[@AustrianAnarchy]

The Halden Calculex is quite the opposite of the iPhone. It continues to work with no way for its makers to "upgrade" it into complete uselessness.

[@HilbertXVI]

AustrianAnarchy Lol wot

[@JimProng]

And it doesn't cost £700.00. You also do not have to pay the manufacturer to add functions. Where it is the same is that if it breaks, its cheaper to buy a new one than to get the old one fixed.

[@aaronmicalowe]

And you never have to recharge it or uninstall broken apps.

[@dafoex]

I'd say it's accurate: someone else's innovation put in a pretty package and sold as new and unique.

[@RWBHere]

@@JimProng It probably cost the equivalent of today's £700 when new though. Maybe a couple of pounds each in 1905, which was at least a month's wages for a labourer. An iPhone costs around 3 weeks of pay for someone on minimum wages today.

[@nerd9684]

I was born in 89, so I didn't get to use this. But I'm geeking out right now about this. Thank you for showing this amazing device.

[@CineMutt]

At college in the early 1960’s in the US, you could identify the math/engineering majors easily by the leather holsters on their belts for carrying their slide rules, and the white plastic pocket protectors with pens of different colors. They wore these proudly.

[@mandolinic]

I recall when I was at school 40+ years ago, one of my maths teachers had a helical slide rule. IIRC, it was about the size of the inner core of a toilet roll, but apparently the scale was about 60" in length.

[@onthespoke2]

ᕮ ͡° ͟ل͜ ͡°ᕭ "It's actually rather lovely the way this moves in and out. It's so beautifully done. It's actually really pleasurable." ᕮ ͡° ͟ل͜ ͡°ᕭ

[@zuutlmna]

My college chemistry instructor used a round slide rule. He was extremely quick with using it, too. Kept it in his shirt pocket.

[@halocemagnum8351]

more of this guy. I love how exciting he makes math!

[@shayan_ecksdee]

No we need more from four handed senpai

[@Blox117]

+Halo CE Magnum too bad bungie nerfed you in halo 2

[@halocemagnum8351]

Blox117 i know what a tragedy.

[@Blox117]

Halo CE Magnum RIP my favorite weapon :(

[@halocemagnum8351]

Blox117 hey you can use me on Halo CE pc, Halo mcc and im Coming soon to halo 5!!

[@RalphDratman]

I loved my slide rule! I taught myself how to use it when I was 13, and it was a great help to me, first in high school chemistry and later in college physics.

[@holdenew]

"It's actually rather lovely, the way this moves in and out. It's so beautifully done; it's actually very pleasurable just doing it like this." - Alex Bellos, 2016

[@ffggddss]

Ah, back to the days when "cursor" meant that hairline thing on a slide rule!

[@DaveScottAggie]

In the printing industry, we still use something, called a proportion wheel (sometimes we call it a reduction wheel). The inner wheel has the size of original, and the outer wheel ha the size of the reproduction (the output). There is a little window with a pointer which will tell you what percentage of enlargement or reduction is necessary to achieve that particular scaling. It is very fast to use. It essentially only does division and multiplication. For example, put original on 8.5 inches, and reproduction on 34 inches, then read out 400%. With it still set at the 400%, look at the 11, and see that the other side of an 8.5x11 sheet of paper will enlarge to 44 inches. That's a fairly simple example, but various tasks come in, almost every day.

[@MrTanker10a]

I still have my yellow PICKETT slide-rule from high school since 1974… I was taught to use the C (Top Scale) and the (D-Bottom Scale) for Multiplication, Division, Fractions and Ratio Calculations...

[@Enkzan]

My grandfather had an identical slide ruler when he studied to become an engineer. When he passed a few years ago, as I started my education, I got it. It's complete with an old weathered leather case. Beautiful piece that I wish I'd been taught to use instead of calculators. :-) Lovely video!

[@IdleGod]

When I was learning to fly, I found a circular slide rule on a cheap watch at a swap meet. The guy had no idea what it was, and thought the ring was some kind of timer. Picked it up for maybe $20. Despite being a huge tech nerd, the watch and slide rule made learning to navigate a lot easier. It's a far cry from GPS, but really useful if you don't have them.

[@zerobeat2020]

I still have my dad's round slide rule which is an "Improved Jeppesen Computer model CR" from 1960, which allows you to calculate a host of things related to aerial navigation, from flying times, speed, distance to fuel consumption, drift, density altitude, airspeed, mach number, as well as ordinary multiplication a division. My dad used this while working as navigator with KLM Royal Dutch Airlines, well before I was born. My dad is no longer with us, but his Jeppesen calculator keeps his memory well alive! He loved flying and particularly navigation. For a while after his retirement he marked navigation exams for the Royal Dutch Flight Academy, now known as the KLM Flight Academy.

[@DancesWithRobots]

You would have had a (somewhat) easier time had you demonstrated multiplication with the C and D scales which were the ones intended for multiplication.

[@davidcole217]

I am one of those 60 + guys who used a slide rule in my Navy schools. The kicker is they were teaching me electronics for digital computers. I had two, one the Navy supplied and a better one my father bought me. It was a great tool. Very easy and fast.

[@lovefrombooks7]

I want to get one of these for those tests my teachers tell me I can't use a calculator. I'll pull out my slide rule and be like "no problem"

[@ffggddss]

+lovefrombooks7 I don't think that'll fly! A slide rule IS a calculator - a mechanical analog calculator. OTOH, your teacher might be impressed that someone your age not only knows what that thing is for, but actually knows how to use it!

[@hugoflores5806]

@@ffggddss estra points for explaining it?

[@ffggddss]

@@hugoflores5806 Explain "mechanical analog calculator"? Well, it's *mechanical,* because it has parts that move, by hand - no battery required. As opposed to electronic, which has circuits and an electronic display. It's *analog,* because it has continuously movable scales, from which numbers are read out; as opposed to digital, which gives its results as multiple digits. And it's a *calculator,* because it can be used to calculate stuff. BTW, an abacus fits all these definitions, too. Fred

[@hugoflores5806]

@@ffggddss No, I was thinking about the log part, and the algorithms for solving different operations

[@ffggddss]

​@@hugoflores5806 You have two scales, C & D, each movable wrt the other. Each has numbers marked where their logarithms are - "1" is at position 0.000 = log1; "2" is at position 0.301 = log2; ... "10" is at position 1.000 = log10. - where position is fraction of the scale length (typically 10 in or 25 cm). So when you move the slide to place the 1 on the C scale over the 2 on the D scale, every number on the C scale is sitting on its own log plus log2, on the D scale. But that means that 4.7 on C sits on 4.7 * 2 = 9.4 on D, etc., so that each marked number on C sits over 2 x itself on D. And so it goes for any multiplier other than 2, that you move the slide to. Fred

[@pmbrig]

In our high school physics class in the late 1960s everyone had to use slide rules. I was the only one who had a circular slide rule instead of a linear one. It was about 10" in diameter (so, not something to slip into a pocket) and had two transparent arms each with a radial hairline, one longer than the other, with the short arm designed to move with the long arm when that was rotated. The primary logarithmic scale around the rim had an effective length of over 30", allowing much better accuracy, and I never had to worry about "running off the scale" when, eg, multiplying 3*4. In addition, it had multiple other scales, including trigonometric scales and a log-log scale (allowing for exponential calculations). I found it much easier to use than the linear ones, and I loved it. It was very finely designed. Sadly, I ditched it at some point after I hadn't needed a slide rule for several years. I wish I still had it.

[@lawrencecalablaster568]

:D I have a slide rule & it is wonderful! I don't use it very much, but I do enjoy using it very much.

[@SlideRulePirate]

+Lawrence Calablaster I hear ya.

[@JohnSmith-do4fm]

+Lawrence Calablaster I collect these bad boys. They're so cool! I try to use them as often as I can to stay proficient with them.

[@alyoshakaramazov8469]

Over 60. I remember my first college chemistry class in 1972. The professor, George Pimentel, had an HP calculator, and that was the first I'd ever seen. He couldn't figure out how to use it the first day. He told us he paid over $400 for it. Everybody carried a slide rule. A year later, nobody carried a slide rule: we could get a Bowmar Brain, which sold for more than $200 in 1972, for $40.00 in 1973. I still used a slide rule in as late as 1976 because we worked out of doors and slide rules were easier to read in the bright sunlight. I used a Pickett circular slide rule then, but I don't know what happened to that one. Now I have an HP calculator program on my iPhone. I've still got my original slide rule from college around on my bookshelf. A Pickett, made in Santa Barbara, Calif. I think I paid $30.00 for it, and that was a huge investment at the time.

[@robertgillcash1696]

I had a watch with a circular slide rule around the outside in approximately 1970. Used it on a few occasions in detention, they'd give you a pile of math problems to do, when you finished them, you could leave. For some reason, I was always finished way faster than anyone else!

[@liquidminds]

thanks, still got the one from my grandfather and now I know how to use it. a bit at least :-)

[@Kneedragon1962]

+liquidminds Learn how to use a conventional slipstick. Once you have that, going to the circular one is pretty easy - it's the same thing but without the ends.

[@General12th]

I mean, it's not like reading a slide rule is a lost art. They're not _that_ hard to figure out.

[@Yupppi]

My cousin brought a similar disc from a vacation trip, but it was like a calender. You could find planet movements and all kinds of crazy details throughout the year from it. It was such a beautiful item, the base was like a stone puck.

[@tehPwnzor7306]

This video finally convinced me to go buy a slide rule (a beautiful Pickett N300-T, with plans to get an N515) after months of researching and looking at them longingly. Thanks, Alex :)

[@shinjinobrave]

6:37 Most phallic thing I've seen all year!

[@Lwyte17]

Calculex is a beautiful creation.

[@sitearm]

In high school (1969-71) my friends and I had shirt-pocket-sized plastic circular slide rules.which we proudly carried in our erm... shirt pockets. So much cooler than nerd pocket protectors or so we thought lol.

[@canisfabico]

My Father is 83 years old and said he remember using this

[@rgfrw]

I'm 73 and still have mine. But I dont use it.

[@General12th]

How old are you? Doesn't matter -- use this whenever you want.

[@glarynth]

2:15 The cursor is also indicating 7 on the D scale, which gives you a way to perform this particular calculation without using the slide at all.

[@TjPhysicist]

i really love the slide rule on my navitimer when i wear it. i don't always wear a watch but that slide rule is super useful for quick calculations and comparisons, esp those where's being off by 2 or 3% isn't really important (tips, comparing costs per unit volume etc)

[@BrianRonald]

You're murdering the precision by using the A and B scales.

[@fjarandag]

+Brian Ronald Of course C+D scales would give more precision, but having to align 10 instead of 1, looking left and divide by 10 would confuse viewers even more.

[@happmacdonald]

+Javier Aranda But I thought that was the entire point of having a ROUND slide rule?! xD

[@ericfrancis7816]

I have my late father's Curta II hand calculator, which he bought in Austria after WWII. It's my greatest treasure.

[@nicholasfazzolari3647]

Rad! I want a slide rule. Anyone manufacturing them these days? I understand we have floating point precision in digital calculators, but I must admit doing my calculations with a slide rule seems like it would be a lot more rewarding!

[@billl605]

Finding the proper decimal point place is a work in itself.

[@noormubeenparbhoo2158]

If you don't an actual one you can find them on some watches

[@johnchestnut5340]

They now have slide rule apps for your phone. Download and enjoy. Imagine using a handheld computer to simulate a slide rule.

[@full-timepog6844]

@@johnchestnut5340 very analogous to things in life.

[@peterbonucci9661]

Amazon has round ones available from Japan. That may be the only source of new mathematical ones.

[@MaoRuiqi]

You missed mentioning the monster slide rule hung above the chalk board in engineering classes. Bold and audacious! Perhaps, by your time, such beauties were already rendered to firewood.

[@oundhakar]

You ought to have used the C and D scales, which are twice as long as the A and B scales.

[@erikwern144]

My Uncle- Carl Wern- received a patent in 1968 for his ABC circular slide rule which included decimal points. This "unfair" advantage led many school teachers banning its use in the classroom. BTW, I have a few of these slide rules in mint condition for sale.

[@klausstock8020]

So nice that you propose to me! I will, of course, accept the Calculex.

[@SuicidialDolphin]

So this is the son of the abacus?

[@EHaraka]

+Cyberpunk Alchemist Abacus is a digital machine, this one is analog. So, hmm... not quite.

[@nicosmind3]

+Cyberpunk Alchemist I would think an abacus is superior. I can remember learning one in school, but i was surprised we didnt use them more often. They were an easy and quick way to do math. And we should have stuck with them long enough to get the basic principles stuck in our heads. After all its how the Japanese do speed math!

[@HarrisFalk]

+nicosmind3 The abacus is superior for addition and subtraction, for all other maths the slide rule is superior.

[@SamsUndertale]

+EHaraka An abacus is an analog machine....

[@lin4cba]

+EHaraka Er....how the heck is an Abacus a digital machine? (I mean the original one, of course)

[@CreationSGame01]

You can hear the passion in his voice.

[@saboo_tage]

It is kinda like an iphone, it doesn't have a headphone jack either

[@HJPorschen]

When I studied mechanical engineering in the late 1960s the slide rule was the only tool we had and were allowed to use in exams. And I still like them, and have a collection of over 40 different ones. Just for fun several years ago I have written a simulation of a Rietz model slide rule which still works on Windows.

[@scowell]

Wonderful video... have you done one on the Curta yet?

[@tylerljohnson]

+1 for the curta, I was thinking the same. it would be interesting to have a curta-like machine that could do trigonometric calculations.

[@tylerljohnson]

looks like numberphile did do a video of the curta, the same guy has one as well.

[@forkontaerialis5347]

If you ever needed to do fast, approximate, analogue calculations on the fly, and it was 1906 you could whisk this out.... Oh, brilliant. Fast, approximate, analogue calculations come up every other day, and almost never without time constraints. This seems perfect for all of my needs, where can I order one. XD

[@mikebauer9948]

(follow-up to below) of course there was some horsing around with them as swords, we used to wear them in scabbards on belt loops. Typically, scales A and B were for square and square root calcs, scales C and D were primary for mult and div, as they were full-length and thus more precise. Typically also, in school settings, math classes required fully reduced answers, such as "3pi/2" rather than the slide rule numerical approx answer, although you'd use the SR to check and gain practice useful for science classes. In the sixties and early seventies, professional offices were already transitioning to desktop electronic calculators before pocket calcs killed off the SRs entirely for most uses.

[@ulilulable]

5 years ago, I aced a university physics' exam using only a slide rule and a pencil... :) (Had to do many extra interim calculation steps compared to my peers with their fancy electronic calculators. Still so worth it.)

[@jpmac098]

We use a very similar tool to this in aviation called an E6-B. It's pretty slow compared to using a calculator but it works.

[@Forrestman69]

Pilots around the world still use circular slide rules everyday in the forms of E6-Bs and CR-3s.

[@petar_donchev]

My father was a pilot / navigator until the 80s and he had exactly the same ruler plus a large rectangular one with circular part. Besides that all routes manually calculated and laid out on drawing paper. Flying used to take considerable math skills.

[@marsgal42]

I'm a pilot and I use an E6-B circular slide rule. It provides answers quickly to common problems (speed/distance/time, wind drift, etc.) and doesn't need batteries.

[@enough_b]

"It's actually rather lovely, the way this moves in and out, it's so beautifully done, this instrument, it's actually really pleasurable just going like this..." Had to.

[@dave5194]

Oh my, that circular slide rule is just absolutely beautiful! I must have one.

[@chirhoiota885]

Forget Common Core. Kids just need to learn slide rules again.

[@darylcheshire1618]

I used to use logrithms in chemistry and I’d use a slide rule to see if I was close to the answer. Those 4 digit atomic weights would fill a page of workings. With just logs I had no idea if my answer was in the ball park but the slide rule helped me. My physics teacher told me that slide rules were banned in the early ‘70s because they were expensive and those who could afford them did so much better than those without. I remember the Sharp Elsimate which could only show three digits at a time and cost about $250, still more than the weekly wage in the mid ‘70s. In college, I remember this guy at the front had this magnificant slide rule which was about 4 inches wide, had two sliding scales and stood on four feet. we were in awe of it until the HP 45 came out.

[@0o32]

I have just bought one

[@00Skyfox]

I use the E6B circular slide rule flight calculator in aviation. Same principle, and works really quite elegantly.

[@jeffreyjefferson6047]

How can you possibly compare a beautiful, innovitave, elegantly designed, sleak, high class, easy to use, hardy, strong device to an iPhone? Blasphemy!

[@General12th]

To be perfectly honest, iPhones (and in fact any smartphone) is beautiful, innovative, elegant, sleek, and so on. They are perfectly smooth ingots of glass and metal.

[@SexyStarfleet]

LagiNaLangAko23 It’s funny because iPhones are supported in software far longer than any other smartphone. But you’re right, hur dur iPhone bad apple bad

[@AndrioCelos]

I used to have a watch with a slide rule on it, a circular one used by rotating a ring around the glass. It wasn't very precise at all, but I loved it.

[@inferno7181]

The iphone of slide rules? That really isn't praise for it.

[@General12th]

Should he have said the Galaxy of slide rules? If you don't think the modern phone is sleek and elegant, we have some strong differences in definitions.

[@sebastianjost]

Even if current I iphones aren't that advanced anymore compared to their competitors (they're mostly just overpriced), these saying refer to the first iphone, which was revolutionary at the time.

[@SteveBakerIsHere]

I love my Calculex - and it also sits on the "antiquated tech" display shelf in my office and is sometimes taken down, gently polished and then used to calculate pi times e. I'm jealous that you have the original box...mine only has the steel jewel box plus instruction book. Mine didn't work when I bought it - so I had to dismantle it to clean it. Unfortunately, when you do that - the back and front sides can become misaligned and you have to do some calculations that involve flipping it over in order to deduce the error you've introduced and recalibrate it before reassembly. But it was definitely worth the effort because now it moves smoothly. Somehow, the idea that this thing was to be worn like a pocketwatch in a gentleman engiineer's waistcoat is comforting! I turn to page 31 of the book - where I'm informed as to how to calculate the Indicated Horsepower and the Expansion rate of steam and the Area if the Steam port...and can just imagine some Great Western railway locomotive designer using my Calculex. I think my Calculex must be older than yours because my instruction book doesn't say "REVISED" - so now I have to worry about what errors got fixed in the revision!

[@MazeFrame]

Can someone make a leather-jacket with "Slide rule owners group" stiched on the back?

[@ElectroNeutrino]

Would it be abelian or non-abelian?

[@cutecommie]

smartmusicfreak Asking the real questions.

[@pauloconnor2980]

You'd get beaten to death if you wore one of those in Frankston!!!!

[@CODCritic101]

The pic of buzz in the space ship with a floating slide rule smoking a pipe is so badass lol

[@bestpseudonym1693]

so i get home after my history teacher makes an anecdote about slide rulers and i see this

[@911gpd]

This thing rules... sorry...

[@leslievaughn1047]

911gp used to.....

[@Radditz770]

I got both my grandads' personal ones when they passed away, and they are just normal ones like the one you're holding but I know one of my grandad, on dad's side, had made his own like box with his name engraved that he kept it in, it's so cool! x3

[@SlideRulePirate]

+Radditz770 Treasures indeed.

[@InfinitelyManic]

I wear a circular slide rule every day - Breitling B-2. I also have a rectangular bamboo one at home.. somewhere.

[@johnfenton3699]

Courtesy of my father-in-law, I have a cylindrical slide rule. It has a 60 inch scale length, which permits meaningful calculations to 3 significant figures

[@willemkossen]

I love this. I have two old sliderules and learned how to use them because i wanted to find out. Its ingenious. I love that circular one! Great stuff!!!

[@alan2here]

Can use super-log, the inverse of hyper-operation 4, to do powers?

[@NotAUtubeCeleb]

+Alan Tennant nothing uses tetration

[@alan2here]

+HybridNeos It would be useful if it works like this, because powers are a more common operation and thats the one you'd end up with finding. X^Y

[@alan2here]

+Alan Tennant Powers are more common than titration I mean, and much harder to do mentally than multiplication.

[@JohnSmith-do4fm]

+Alan Tennant Most slide rules log-log scales for powers.

[@alan2here]

It does works for powers too? :¬o Impressive.

[@gameguy99ful]

I love math and I love wristwatches, my favorite kinds of watches include a circular slide rule, around the outside of the watch :)

[@dannygjk]

Those types of instruments were also used in submarines to do angle solving for aiming torpedoes, (at least those subs that didn't have sophisticated TDC's).

[@ericstoverink6579]

iPhone of slide rules. So you mean that it's overpriced even though it does the same things as other less expensive slide rules, and the people who buy them only do so for the brand name?

[@jimharmon9917]

Pretty much, yes.

[@jpdemer55]

And an Aston-Martin V-12 Vantage takes you to the drugstore, same as a Honda Civic. There's a bit more to it than four wheels and a motor.

[@daleburgess3318]

I still use my Pickett 110ES circular slide rule today for on the fly approximations! That's a sweet tool, though. Elegant ^ (n+1)

[@alanduffy7497]

Another beautiful slide rule is found on the Breitling Navitimer. It too is a circular slide rule.

[@JennyEverywhere]

I've been collecting slide rules for years. I don't have a Calculex, but I've got several Russian KL-1 "pocket watch" slide rules that look similar, and several other circular rules by the Japanese company Concise. I have some rules that are interesting because of their usage in literature, such as my K&E 20-inch log-log duplex decitrig, as featured in Robert Heinlein's novel _Have Spacesuit, Will Travel._ It's an elegant device, almost two feet long (it improves accuracy) and made of gorgeous mahogany wood with white celluloid scales. I have several Faber-Castell rules, including a pocket sized rule with an Addiator, a kind of mechanical adding and subtracting device, on the back of the rule. It's a little gimmicky, but that's ok. I also have it's penultimate big brother, the 2/83n, the Novo-Duplex, with 30 scales for many different calculations. It was their next to last rule they ever made, succeeded only by the Mathema, which i do not have. I have the pocket sized Pickett N600-ES, the one that went to the moon. (Mine didn't go to the moon, it's just the same model!) I love slide rules. They help you do math, but they don't replace knowledge about math, as you need to know what to calculate and why. You can't just plug in numbers with buttons and get an answer. It just helps you crunch the fiddly bits.

[@AngelTiel]

Perfect. The first video I've found which is accessible to young adults in a non-cringey way. Thank-you.

[@spicytaco2400]

I learned how to use a slide rule and i'm only 17.

[@NetAndyCz]

Well, it is not that hard to operate...

[@jessstuart7495]

Use the C and D scales for multiplication. You get twice the precision. I think all middle-school kids should have to make a little paper slide-rule when they are first learning about logarithms. If you don't need much precision, slide rules can be faster than calculators. If you need to multiply or divide a bunch of numbers by the same factor, (and no spreadsheet handy) you don't need to readjust the position of the scales. Nomographs are fun too. I have a reactance nomograph I use when designing filters because it is much quicker than calculating impedances for caps and inductors with a calculator.

[@jean-paul7251]

Agree use C and D. Would make kids think better

[@johnpeake7847]

Alex, The price 1/6 for the Calculex is pronounced 'one and six', meaning one shilling and sixpence, in old money, pre-decimalisation. It converts to 7.5 pence!

[@jesusthroughmary]

Come on, I'm a 36-year-old American and I know that that price is 1 shilling and sixpence, i.e 1.5 shillings or 18 pence (18/240 of a pound).

[@Dracopol]

The symbology was forgotten. Sometimes written as 1 s. 6 d. (d. for pence is a stretch but the Romans left their influence by talking about the denarius!) but in quick symbols it was 1/ 6 and often confused as a kind of fraction 1/6.

[@okaro6595]

That was the price of the manual.

[@fjarandag]

That Halden looks gorgeous, but I think a pocket-size slide rule such as a Pickett N600-ES in a proper case is just as convenient.

[@Postghost]

iPhone of the slide rule? so it's a slide rule with deliberately stifled functionality and popularized by an overpriced, underhanded, hype-marketing scheme? ...weird.

[@MegaScytheman]

you forgot to mention how it gets bigger every year

[@KiloOscarZulu]

My brother had an aviator watch with a circular bezel with the slide rule built into the bezel.

[@jameswalley134]

The circular slide-rule is virtually the same as the Aviation circular slide-rule which is still used extensively today. It's much quicker to use than an electronic calculator, and several computations can be read without having to change the original position of the inner & outer scale.