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The compact pairing of helical scales with a tubular or cylindrical body created some endearing high-precision slide rules.

[CARBIC] [Fisher ] [Lafay] [long-scale] [Otis King] [R.H. Smith] 

Bij het lezen en het artikel “Het ei van Columbus of misschien toch niet?” van Chris Hakkaart in MIR 90, ging bij mij een belletje rinkelen.

When reading the article “Columbus' egg or maybe not?” by Chris Hakkaart in MIR 90 it rang a bell with me.

[Atpress] [chord] [copyright] [Dutch] [Jasperse] [keyborad] [music] [slide chart] [string instrument] [TELEAC]

The most endearing quality of the slide rule is its endless adaptability - from calculating catenaries to the odds of winning

[advantage play] [ALRO] [betting] [calculator] [gambling] [horse racing] [Lawrence] [poker] [poly-slide] [roulette]

The most endearing quality of the slide rule is its endless adaptability - from organ pipes to human hearts.

[cardiac] [ cardiologist ] [cardiology] [ECG] [EKAGNOST] [EKG] [electrocardiogram] [Faber-Castell] [heartbeat] [Medical] [pulse] [QTc] [QT interval] [RR interval] [Sandera] [Sinus Rhythm] 

Long Scale types are an alternative to just stretching out C & D scales for more accuracy

[accuracy] [benchmark] [circular] [drum] [linear] [long-scale] [precision]

Should you go for the “best model” or the “best buy”?

[accuracy] [Aristo] [Blundell] [Consumer Organisation] [convenience] [Dargue] [durability] [Ecobra] [Faber-Castell] [Hellerman] [Hemmi] [legibility] [linear] [Nestler] [precision] [Simplon] [student] [test] [Thornton] [UNIQUE]

I grew up in a pre-decimal imperial weights and measures world. However, I and many fellow “baby boomers” now find it difficult to remember the era when shopkeepers and office workers had to do everyday transactions in what for anyone outside the United States (US), Myanmar and Liberia would now consider strange and irrational imperial units. 

[conformature] [gauge] [glove] [hat] [Hatters] [measure] [metric] [Milliners] [shoe]  

Barbotheu: the unknown French slide rule (n.b. my English translation of Harry van Doren's original article in Dutch).

[finger button] [MIR] [Paris] [Tavernier-Gravet] [translation]

The most endearing quality of the slide rule is its endless adaptability - from organ pipes to human hearts.

[cardiac] [ cardiologist ] [ECG] [EKAGNOST] [EKG] [electrocardiogram] [Faber-Castell] [heartbeat] [Medical] [pulse] [QTc] [QT interval] [RR interval] [Sandera] [Sinus Rhythm] 

For 400 years the slide rule was an invaluable calculating aid. But there was another side to Oughtred’s invention. It proved highly adaptable and was used in many diverse ways …. even cheese making!

[butterfat] [caseiculture] [curd] [Dutch] [Henning] [milk] [Wezep] [whey] [yield] 

"When the result is easier to see but wrong!"

It is apt for the UKSRC Gazette’s visionary 2020 edition to highlight a slide rule innovation to ease eye strain.

[accuracy] [acuity] [interpolation] [legible] [Snellen] [Snodgrass] [UNIQUE]

Heijdeman: Nederlands Rekenliniaal Erfgoed

Heijdeman: Dutch Slide Rule Heritage

[Book] [Dutch] [Heydeman] [instruction] [manual] [Thys] [Mierloo] [Vaes]

A description of a mystery wooden oversized “one-off” slide rule from the 1950s with an unusual multi-slide layout by East German maker Alfred Kuhmann (ALKU) - 12 of the 14 non-standard scales appear chemical related and somewhat similar to the later Hemmi model 405 for Portland cement. 

[ composition] [concrete] [DDR] [poly-slide] [​

The IM2019 is the 25th anniversary meeting but how did it all start?

[1995] [International] [Scheveningen] [Utrecht]

Overlooked Nestler Models.

Subconsciously I make word associations with certain slide rule makers. Rectilinear models I always associate with the German maker Nestler. So when I came across a circular Nestler it struck me as odd.​

[circular] [co-branding] [commissions] [Controller] [military] [Nestler]  

A c1950 mystery chemical slide rule by German maker Alfred Kuhmann (ALKU).

[DDR] [poly-slide] ​

A delicious misquote reveals overlooked innovation. The literal quote was “The Fastest Slide Rule in Whitehall” and is attributable to the British science fiction writer and futurist Sir Arthur C. Clarke, CBE, FRAS (1917–2008).

Before becoming a world-famous writer Arthur C. Clarke was a civil servant working for the UK government and the Simplon XL-10 slide rule he used to audit teachers’ pensions inspired the memorable quotation.

[Bakelite] [Bilateral] [Catalin] [Dargue] [Honduras] [Simplon] [Sub-Ivory] [Uniface]

You say eyether and I say either,
You say runner and I say cursor,
Eyether, either, runner, cursor,
Let’s call the whole thing off!

[Accuracy] [Awards] [Cursor] [Enrichments] [Goulding] [Hair] [Interpolation] [Oscar] [Magnify] [Magnifiers] [Newton] [Radial] [Razzie] [Refinements] [Replacements] [Runner] 

De hybride TR series van Faber-Castell (F-C), met de combinatie van een elektronische rekenmachine en een rekenliniaal, zijn apart. In Duitsland versleten F-C TR batterijsleuven tegen een klein vergoeding op te knappen zijn.

The hybrid TR series from Faber-Castell (F-C), with the combination of an electronic calculator and a slide rule, are different. For a modest fee worn out F-C TR rechargeable battery units can be refurbished in Germany.

[Charger] [Dutch]

UK maker Blundell Harling (BH) was with over 5000 models, the champion producer of specially commissioned slide rules. But not all of them were BH branded. Help in identifying such unbranded but HM-made slide rules came in 2000 when a list of P Numbers showing the serial numbers of such commissions was published. In 2017 it came to light that some unbranded models can also carry a M Number (n.b. co-authored with Peter Soole).

[Blundell] [Unbranded]   

Slide rule collectors are always looking out for a lost gem or the big find. More than often all we ever find is another cardboard or cheap plastic slide rule with just a few logarithmic scales. But some of these simple & everyday looking “ugly ducklings” can, like in the Hans Christian Andersen fairy tale, turn out to be amazing “swans”. This compilation (descriptions & images) features many such often overlooked beauties divided over 12 themed galleries (n.b. co-authored with some members of the German RST collectors group).

[Health & Medical] [Money] [Merchants] [Food & Beverages] [Construction & Home Improvement] [Heating] [Arears & Volumes] [Calendar] [Cars] [Speed] [Photography] [All-in-One]

Surprisingly right up to the 1960s “how to use a slide rule” sessions were not taught in secondary schools. In fact in most countries no course on calculating with a slide rule ever became part of their national school curriculum.

[35mm] [Aristo] [blackboard] [Blundell] [carousel] [demonstration] [dia] [education] [Faber-Castell] [instruction] [multimedia] [OHP] [Pickett] [projector] [teaching] [Thornton] [training]

Your eyes can deceive you, don’t trust them. There are always exceptions and sometimes we only see what we want to see. 

[British] [efficiency] [electrical] [English Electric] [Lilliput] [Obi-Wan] [PF] [Power Factor] [Riches] [Star Wars] [Thornton]

Wanneer je in het buitenland op zoek voor zoiets als het lang vergeten rekenliniaal bent, kan zelfs in sommige delen van Europa een Engels vertaling of gebarentaal niet genoeg zijn. Een lijst met de inheemse spelling voor een rekenliniaal kan helpen. 

When hunting for something like a “long forgotten” slide rule in other continents or even in some parts of Europe, English or hand/foot sign language is often not enough. Knowing the native spelling can help. 

[Dutch] [foreign] [translate] [translation]

Iedere verzamelaar van rekeninstrumenten heeft vanzelfsprekend enige affiniteit met rekenen. De klassieke en bijzondere Gulden Snee verhouding φ = 1,618 (ofwel phi) is de basis voor een speciaal in opdracht gemaakt installatie ik heb om mijn tuin te verfraaien.

Every collector of calculating devices has a certain affinity with mathematics and calculating. The classic and extraordinary “Golden Ratio” (φ = 1,618) is the basis for the specially commissioned installation I have in my garden.

[Dutch] [sculpture]

Bij ‘vroeger’ denken we meestal eerst aan de geschiedenis van landen, van mensen, van dorpen. Maar vroeger werden ook gewone dingen heel anders gedaan dan nu het geval is.

When thinking about the past we usually start with the history of countries, of people and of villages. But in such bygone days many everyday activities were done very differently than today.

[ALRO] [bulbs] [forcing] [Dutch] [History] [Mannheim] [Muiderkring] [Oughtred] [radio] [Sassenheim] [SOS]

Remarkably the basic design of the slide rule has lent itself to many unlikely trades and professions – usually through innovative scales but for one all the scales are just swatches of colour! 

[chromatic] [color] [saturated] [slider] [unsaturated] [WK-Farbschieber] [WK-Wohnen]

A regime of eating habits, philosophies and practices by which body fat is managed and controlled. 

[Anthropometry] [BMI] [calculator] [health] [obesity] [tape measure] [Waist-to-Hip]

Given what they replaced it feels disparaging, impolite and almost blasphemous to point out that logarithmic tables were sadly error prone and irritatingly awkward to use. Surely graphic logarithmic tables must have been the answer! Paradoxically they did not but they did have an unexpected link to certain models of slide rules.

 [Addiator] [Faber-Castell] [Haro ] [Kienbaum] [Koch] [Kubler] [Lacroix] [Lalanne] [Leder] [Loewe] [logs] [Maximator] [Napier] [nomogram] [Obbink] [Pressler] [Putschbach] [Ragot] [Rohrberg] [Tichy] 

A description of a mystery L.P. Casella. wooden desktop “one-off” slide rule (made with no cursor) from the 1930s with various inexplicable scales, many of which are expanded versions for extra accuracy. All the scales appear non-standard. 

[Harling}

A description of Radiation Dosage Calculator for Contamination Over Land and Dark-Room Exposure Time Calculator show prototypes.These stainless-steel calculators, professionally made to the highest standards, were “specially commissioned” by a Dutch engineer, Dr. Ir. Ing. J.W. van Beek, in the 1970s. He made so that they could become lasting tributes to the much-loved originals he had personally used.

 [BRL] [Orr] [TUD]

Despite being past the heyday of the Second Industrial Revolution “engineers in tights” made sure slide rule innovation persisted well into its twilight years. 

[57/74] [ARISTO] [Blundell] [denier] [Faber-Castell] [LOGA] [Nestler] [Schirdewan] [Seehase] [System]

Given what they replaced it seems disparaging, impolite and almost blasphemous to point out that logarithmic tables were sadly error prone and irritatingly awkward to use! 

[Kienbaum] [Koch] [Kubler] [Lacroix] [Leder] [Loewe] [logs] [Napier] [nomogram] [Obbink] [Pressler] [Putschbach] [Ragot] [Rohrberg] [Tichy]

Despite discovering yet another shocking new category, the rule clip, most clips remain rare and mostly American. 

[Dietzgen] [Eckel] [Faber-Castell] [Lafayette] [Pickett] [P&E] [POST]

Collectors of slide rules are a chatty and sociable bunch – inevitably the conversation at some point turns to: “well, just how big is your collection?” 

[standard] [measure] [distance] [speed]

How could anything ever surpass the Texas Magnum of Skip Solberg and Jay Francis? But when it comes to the largest slide rule ever built, it has a Russian challenger - Bashkir State University! 

[extra-long] [Ufa]

A description of a special purpose DUPA wooden poly-slide duplex slide rule for calculating the line loss and voltage drop on electrical distribution lines.

[Dennert] [D&P] [Esser] [K&E] [Keuffel] [nomogram] [transmission]

A description of an early 20th century English “oversized” wooden desktop “one-off” slide rule (with an unusual fixed cursor) for the textile trade. 

[British] [extra-long] [imperial] [poly-slide] [Rankin]

Despite sounding weird and as challenging other visual oxymorons like “invisible ink” and “bricked-up windows” there was a time when computer programmers needed some seemingly old-fashioned calculating and conversion aids. 

[Abacus] [adder] [binary] [Canon] [colour] [color] [Colossus] [Comfort] [Clopper] [Coldner] [decimalisation] [digital] [EDI] [Hexadaisy] [Hexadat] [Hexadder] [hexadecimal] [HP] [IBM] [imperial] [Kubler] [octal] [Sterling] [TI] [Turku] [UNIVAC]

Georg Stibitz’s invention was surprisingly neither unique nor exclusive! This addendum lists 20 other patented band- and pape calculators and shouldd be read in conjunction with the main Stibitz article (JOS Vol. 21 No. 1).

But why did so many clever inventors come up with film-based calculating machines?

George R. Stibitz was special. He was a prolific inventor and won many prestigious honours and awards. He is often rightly cited as: “The father of the modern digital computer”. Sadly the military overtones associated with the Stibitz Film Slide Rule probably stopped it (and still does) getting the recognition and publicity it rightly deserved (n.b. co-authored with Dieter von Jezierski). 

[Army] [NDRC]

It is easy to think that slide rule innovation and creativity in the 20th century was largely the domain of commercial greats like Nestler, Faber-Castell, Keuffel & Esser, etc. But like its maligned UK “counterpart” Unique, the ubiquitous Lawrence is wrongly and unfairly just seen as an American “pile ‘em high and sell ‘em cheap” maker of slide rules. The Lawrence legacy is undoubtedly an unsurpassed portfolio of surprisingly innovative and inventive slide rules.

[25¢] [Bozarth] [brand] [Engineering] [Indiana] [Lee] [OEM] [Peru] [Snyder] [Wabash]

It happens a lot – well, it happens a lot to me. I see an intriguing slide rule or something a bit different and I think I am sure I have seen something like that before. This time a faint memory solved a mystery. 

[Graphoplex] [tensioning]

Despite discovering a new category, the clip rule, pouch or rule clips remain rare and mostly American. 

[Baux-Arts] [concrete] [Eckel] [Faber-Castell] [Parisan] [Pickett] [P&E]

At the end of the 19th century an unsung and now sadly largely forgotten instrument maker and retailer had its heyday.

[ACE] [Army] [Bisley] [Bosworth] [Goble] [Goldsmith] [Hall] [M.T.] [optics] [Norden] [NRA] [RHS] [Wimbledon]

In deze tijd van het globale bereik van Internet, zijn nationale “verkoopgrenzen” of zelfs die binnen de Benelux vaak niet meer relevant of actueel. Maar er is een tijd geweest, dat de keuze van een handelsmerk of merknaam in het Nederlands een belangrijk deel van de verkoopstrategie was. 

In these days of global reach through the Internet national “selling boundaries”, even within the Benelux, are often irrelevant or out-of-date. But there was a time when the choice of a trademark or brand name was a major part of any sales strategy. 

[Dutch] [brand] [MERK-o-GRAAF]

A description of a Nestler 100cm desktop model 24b slide rule (n.b. description includes generic production stats, etc for desktop and demonstration slide rules). 

[extra-long]

A description of a large “one-off” slide rule designed for the imperial-based calculations prevalent in the steel trade. 

[Blundell] [poly-slide]

A description of a “one-off” specialist agricultural slide rule/chart to calculate the pulling power of a tractor.

 [agricultural] [engine] [husbandry] [Hyatt]

For most, twaddell is an outdated expression to describe some written or spoken gibberish but even if it sounds too ridiculous for words, it is also the name of a special scale for measuring the acidity or sweetness of liquids. 

[alcohol] [British] [density] [hydromter] [Lovi] [Macintosh] [pottery] [SG] [slip] [strength] [tanning] [Wilson]

Why yet another update? One of Andy Warhol’s (1928-1987) more famous quotes is: “... everyone will be famous for 15 minutes.” It seems my 15 minutes of fame may come from pouch clips! 

[ARISTO] [DIETZGEN] [ECOBRA] [Faber-Castell]

Surely a wooden slide rule must be more tactile than one made of plastic? If they could talk, a fine boxwood slide rule with a rich patina must have “lived” more and have more stories to tell than any plastic contemporary. The one exception to the rule should have been an all-Bakelite slide rule but after showing great promise as a raw material the Bakelite process turned out to be fatally flawed. 

[angle] [Baekeland] [Blundell] [brand] [BRL] [enamalled] Hammelburger] [Holophane] [illumination] [tensioning]

As soon as currencies were established, bartering fell out of fashion and multiplication skills were needed to succeed in business. However, for over a century the calculating aid of choice for trade and commerce was the Ready Reckoner and not the slide rule.

[Addiator] [bareme] [Blundell] [deciimalisation] [Faber-Castell] [Fenning] [Flash] [Gall] [HABS] [hybrids] [imperial] [Inglis] [Metric] [Nestler] [Robson] [Reckoner] [tables] [Unique]

I have often followed a promising URL only to end up down a “blind alley”. But you can also stumble upon little gems – like the Croquet Circular Slide Rule. 

[handicap] [Nels] [Plummer] [step-calculator] [unisex] [Wimbledon]

A description of a mystery “one-off” slide rule with  bands of colour rather than scales. Possibly some kind of colour mixing aid. 

[color] [poly-slide] [sampling]

A description of an unusually designed “one-off” slide rule of Dutch (PTT) origin. Originally thought to be for calculating the combined signal loss for a given number of telephone subscribers but at the IM2014 in Delft its true provenance of dimensioning for a Dutch cable radio (“Draadomroep”) system was presented. This subscriber based system operated from 1930s to the 1970s. 

[CWP] [transmission]

Instead of just calculating the profit, a specialist slide rule for heating oil developed by Shell (SNV) was the reason for the profit and the greatly increased Shell's market share! 

[ARISTO] [boilers] [BP] [central-heating] [CO] [efficiency] [Faber-Castell] [Nestler] [temperature] [soot] [Unique]

The setting of a bespoke tailor’s workshop which was developed into a late 1960’s television comedy series could so easily have contained the two intriguing Tailor’s Squares which are the basis for this article (n.b. co-authored with Jenny Hutchinson). 

[cutter] [Mahon] [Rabone] [ready-to-wear] [Preston] [Savile] [Vincent] [Williamson]

Slide rules from the Southern Hemisphere are mostly unknown, scarce and one in particular, shrouded in mystery. 

[Australia] [AWA] [D/L] [electronic] [Faber-Castell] [Home] [Nagaoka] [Service] [Sydney]

Het spreekwoord luidt: ”Elke zot heeft zijn marmot” of iedereen heeft wel een hobby. Voor velen is het ideaal wanneer je van je hobby je beroep kunt maken. 

The saying goes, "Everybody needs an interest" or everyone has a hobby. For many it is ideal when you can turn your hobby into your profession. 

[Dutch] [Gunter] [Mannheim] [Napier] [Oughtred]

A description of a “one-off” mystery desktop slide rule with logarithmic scales for imperial units. 

[British] [timber]

A pair of “one-off” slide rules for oil industry related calculations by Gasiorowski.

[BP] [chemical] [nomogram]

Despite finding a few new examples, pouch clips remain rare and mostly American. 

[brand] [Eckel] [Escher] Keuffel] [K&E] [Pickett] [P&E] [POST] [UTO]

In plaats van slechts de winst uit te rekenen, een specialistische rekenliniaal ontwikkeld door Shell (SNV) voor olie gestookte C.V. ketels was de reden voor de winst en een aanzienlijke toename van Shell’s marktaandeel!

Instead of just calculating the profit, a specialist slide rule for heating oil developed by Shell (SNV) was the reason for the profit and the greatly increased Shell’s market share!

[boilers] [central-heating] [CO] [Dutch] [efficiency] [Faber-Castell] [temperature] [soot] N.B. prequel to extended version published later in IM2008 Proceedings

Unlike Anthony Manville (UKSRC: SS no. 24), I cannot play an instrument. However, I like to "jazz up" and keep my collection interesting by adding related colourful attributes - like a slide rule vinyl LP. 

[acoustic] [Johnson] [music] [Parlophone] [Winding]

Expanded and extended version of the the original 2005 publication but now showing how many aspects related to music are linked to mathematics, logarithms and slide rules. 

[acoustic] [Blundell] [carillon] [Faber-Castell] [Fenning] [Fritsen][harpsichord] [harmonics] [IWA] [Lawrence] [Lloyd] [nomogram] [Petit] [piano] [pipes] [organ] [Rensch] [Taylor] [transposer]

Finding a rare “lost gem” in a flea market gives an adrenalin rush that modern on-line auctions can never match. But what makes a slide rule rare is not straightforward as “rare” can turn out to be a simple pouch clip. 

[ARISTO] [brand] [DIETZGEN] [[Eckel] [Escher] [Faber-Castell] [Keuffel] [K&E] [Leningrad] [Pickett] [P&E] [POST] [RICOH] [SIC]

Voor de hedendaagse scholieren en studenten is het nauwelijks te geloven dat tot omstreeks 1970 een 17de eeuwse uitvinding van een Engelse dominee het belangrijkste rekenkundige instrument was! 

For today’s schoolchildren and students it is hard to believe that until about 1970 a 17^th century invention by an English clergyman was the most important calculating device! 

[Dutch] [Gunter] [Mannheim] [Napier] [Oughtred]

For centuries the slide rule proved an invaluable calculating aid. But there was another side to Oughtred’s invention. It proved highly adaptable and was used in many diverse ways – even for music! 

[acoustic] [Blundell] [carillon] [Faber-Castell] [Fenning] [Fritsen] [harpsichord] [harmonics] [IWA] [Lawrence] [Lloyd] [nomogram] [Petit] [piano] [pipes] [organ] [Rensch] [Taylor] [transposer]

Peter Soole’s eenvoudige manier om erachter te komen hoe de productie toleranties voor de juistheid zijn gesteld. 

Peter Soole’s simple way to test any manufacture’s tolerances for accuracy. 

[Dutch] [exactness] [precision]

When hunting for something like a “long forgotten” slide rule in other continents or even in some parts of Europe, English or hand/foot sign language is often not enough (n.b. original compilation by KRING member Jaap Dekker). 

[foreign] [translate] [translation]