# "A slide rule is a physical instantiation of multiple nomograms:" T or F? **URL:** \ **Category:** Factual Questions\ **Created:** [November 30, 2012, 8:07am UTC](https://boards.straightdope.com/t/a-slide-rule-is-a-physical-instantiation-of-multiple-nomograms-t-or-f/642552 "2012-11-30T08:07:21Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [November 30, 2012, 8:07am UTC](https://boards.straightdope.com/t/a-slide-rule-is-a-physical-instantiation-of-multiple-nomograms-t-or-f/642552/1 "2012-11-30T08:07:21Z")
See subject, written in telegraphese. While bouncing around on info from a thread on the Atlantic cable, I came across the gorgeous [Smith chart](http://en.wikipedia.org/wiki/Smith_chart), which needless to say was new to me. I first was formally introduced to nomograms when I was in a reading-for-the-blind tape recording project, and I can assure you they definitely tested my attention and descriptive ability. But this idea, the one in quotes, just struck me. I also thought a clock could be described similarly. But then my examples started to run ahead of what I could define for myself as a correct statement, both in its general validity or how it could be sensibly bounded. Hence I submit the query to the masses. ---
**Author:** ![jackdavinci](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackdavinci/32/3259_2.png) [@jackdavinci](https://boards.straightdope.com/u/jackdavinci)\ **Post date:** [November 30, 2012, 8:28am UTC](https://boards.straightdope.com/t/a-slide-rule-is-a-physical-instantiation-of-multiple-nomograms-t-or-f/642552/2 "2012-11-30T08:28:09Z")
Wiki says they are both a “graphical analog computation device”. It’s debatable whether it is more akin to multiple nomograms or one variable nomogram. A clock doesn’t qualify. It measures or indicates rather than computing. ---
**Author:** ![Senegoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senegoid/32/6606_2.png) [@Senegoid](https://boards.straightdope.com/u/Senegoid)\ **Post date:** [November 30, 2012, 11:31am UTC](https://boards.straightdope.com/t/a-slide-rule-is-a-physical-instantiation-of-multiple-nomograms-t-or-f/642552/3 "2012-11-30T11:31:09Z")
Small aircraft pilots have long used a flight calculator for computing mileage, flight times, fuel usage, and vectors. It’s basically a circular slide rule on the front with specific scales useful for a pilot. Turn it over, and the back side is a wind-triangle vector calculator. Photo: [http://www.rekeninstrumenten.nl/pages%20and%20pictures/14761.jpg](http://www.rekeninstrumenten.nl/pages%20and%20pictures/14761.jpg) ETA: Of course, more modernly, this is done by little electronic pocket calculator devices. ---
**Author:** ![Heracles](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/heracles/32/487_2.png) [@Heracles](https://boards.straightdope.com/u/Heracles)\ **Post date:** [November 30, 2012, 12:06pm UTC](https://boards.straightdope.com/t/a-slide-rule-is-a-physical-instantiation-of-multiple-nomograms-t-or-f/642552/4 "2012-11-30T12:06:55Z")
> [@Senegoid](#): > > Small aircraft pilots have long used a flight calculator for computing mileage, flight times, fuel usage, and vectors. > > (…) > > Of course, more modernly, this is done by little electronic pocket calculator devices. No, in the future [they will still use the analog version](http://www.startreknewvoyages.com/?p=1338). 🙂 ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [November 30, 2012, 12:37pm UTC](https://boards.straightdope.com/t/a-slide-rule-is-a-physical-instantiation-of-multiple-nomograms-t-or-f/642552/5 "2012-11-30T12:37:40Z")
The [Wikipedia article on nomograms](http://en.wikipedia.org/wiki/Nomogram) hints that your subject line is not true: > [@Wikipedia](#): > > Nomograms flourished in many different contexts for roughly 75 years because they allowed quick and accurate computations before the age of pocket calculators, making such calculations available to people who did not normally use slide rules… > … > Like a slide rule, a nomogram is a graphical analog computation device, and like the slide rule, its accuracy is limited by the precision with which physical markings can be drawn, reproduced, viewed, and aligned. Most nomograms are used in applications where an approximate answer is appropriate and useful. Alternatively, a nomogram may be used to check an answer obtained from another exact calculation method. The slide rule is intended to be a general-purpose device, while a nomogram is designed to perform a specific calculation, with tables of values effectively built in to the construction of the scales. > … It doesn’t come out and explicitly say that slide rules are not nomograms, but in comparing/contrasting the two, it implies that one is not a subset or type of the other. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [November 30, 2012, 12:42pm UTC](https://boards.straightdope.com/t/a-slide-rule-is-a-physical-instantiation-of-multiple-nomograms-t-or-f/642552/6 "2012-11-30T12:42:41Z")
I suppose the OP is correct, but obly technically – a slide rule in a single setting will provide a nomogram for all the possible ways to break down a number into its multipliers. Moving it along will give all the possible multipliers that produce a different product. But it’s still basically one idea and type of calculation (unless you consider the other scales) I’m fascinated by nomograms. There are entire books and websites devoted to them, and they take a variety of forms and types, and can be used for multiple purposes. That Smith Charet you mentiion, for instance, is mainly used for electrical calculations, but optical thin film designers use it, too, for calculating the transmission of multiple thin films. What I find most fascinating about nomograms isn’t that they give you a way to calculate without a computer (although they do that, too), but that they give you insight into the way quantities are relatred, giving you an instinctive and intuitive feel for relationships that you _don’t_ get from a calculator, or from the explicit functional form of the relationship. They can often be even better than a graph or plot of the relationship. As an example, one other thing you can get from a slide rule (although it isn’t what it was made for, as an “instantation of multiple nomograms”) is the relative size of the Benford Probabilities. ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [November 30, 2012, 3:01pm UTC](https://boards.straightdope.com/t/a-slide-rule-is-a-physical-instantiation-of-multiple-nomograms-t-or-f/642552/7 "2012-11-30T15:01:03Z")
> [@Heracles](#): > > No, in the future [they will still use the analog version](http://www.startreknewvoyages.com/?p=1338). 🙂 Beautiful rule. I like it better in the new configuration. Very, very smart prop designer. I’m still thinking about the posts here, but I sense a common trap: citing Wiki as if it has definitive force. It’s just some dude/ette, and silent approval or not caring all that much by a few others, most notably, of course, the more speculative the question is. I’m not disputing them here (but could), nor disagreeing/picking any arguments in this case (although I might) , but this is the SD, after all. ---
**Author:** ![Kevbo](https://avatars.discourse-cdn.com/v4/letter/k/e47774/32.png) [@Kevbo](https://boards.straightdope.com/u/Kevbo)\ **Post date:** [November 30, 2012, 4:41pm UTC](https://boards.straightdope.com/t/a-slide-rule-is-a-physical-instantiation-of-multiple-nomograms-t-or-f/642552/8 "2012-11-30T16:41:32Z")
> [@Heracles](#): > > No, in the future [they will still use the analog version](http://www.startreknewvoyages.com/?p=1338). 🙂 It’s OK. Vulcan vision allows him to read that sucker to 4-5 decimal places, which he then prefaces with “approximately” when relaying the answer to his superior. And this brings me to the point that slide rules and nomograms teach another valuable lesson: For many applications a fairly crude estimate (+/- 5% say) is perfectly acceptable, and will work just as well as if it had been calculated to within a gnat’s ass. Often as not, at least one of the inputs are not exactly known in the first place, so finding an answer with 3-4 decimal places of precision is just silly. ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [November 30, 2012, 5:38pm UTC](https://boards.straightdope.com/t/a-slide-rule-is-a-physical-instantiation-of-multiple-nomograms-t-or-f/642552/9 "2012-11-30T17:38:46Z")
> [@CalMeacham](#): > > There are entire books and websites devoted to them… Could you help out my sorry lazy ass with a few cites? I can see really getting back into this. I have spent much private and professional time on visual display of information, and it’s time to revisit. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [November 30, 2012, 5:52pm UTC](https://boards.straightdope.com/t/a-slide-rule-is-a-physical-instantiation-of-multiple-nomograms-t-or-f/642552/10 "2012-11-30T17:52:18Z")
> [@Leo\_Bloom](#): > > Could you help out my sorry lazy ass with a few cites? I can see really getting back into this. > > I have spent much private and professional time on visual display of information, and it’s time to revisit. I’d have to look them up. The library when I worked a few jobs back had a couple of books on the topic. Here are a few cites: [http://mathforum.org/library/drmath/view/63338.html](http://mathforum.org/library/drmath/view/63338.html) > **[Charts & Nomographs for Electronics Technicians & Engineers: D Moffat:...](https://www.amazon.com/Charts-Nomographs-Electronics-Technicians-Engineers/dp/B000CRKGNW)** > > Charts & Nomographs for Electronics Technicians & Engineers \[D Moffat\] on Amazon.com. \*FREE\* shipping on qualifying offers. Charts & Nomographs for Electronics Technicians & Engineers > **[Graphical and Mechanical Computation - Including Nomographs and Mechanical...](https://www.amazon.com/Graphical-Mechanical-Computation-Nomographs-Integration/dp/1929148380)** > > Buy Graphical and Mechanical Computation - Including Nomographs and Mechanical Integration on Amazon.com ✓ FREE SHIPPING on qualified orders > **[The History and Development of Nomography: Evesham, Dr. H. A., Riddell, Brenda:...](https://www.amazon.com/History-Development-Nomography-Dr-Evesham/dp/1456479628)** > > Buy The History and Development of Nomography on Amazon.com ✓ FREE SHIPPING on qualified orders ---
**Author:** ![standingwave](https://avatars.discourse-cdn.com/v4/letter/s/9de0a6/32.png) [@standingwave](https://boards.straightdope.com/u/standingwave)\ **Post date:** [November 30, 2012, 6:21pm UTC](https://boards.straightdope.com/t/a-slide-rule-is-a-physical-instantiation-of-multiple-nomograms-t-or-f/642552/11 "2012-11-30T18:21:42Z")
> [@Leo\_Bloom](#): > > See subject, written in telegraphese. While bouncing around on info from a thread on the Atlantic cable, I came across the gorgeous [Smith chart](http://en.wikipedia.org/wiki/Smith_chart), which needless to say was new to me. I’ve used the Smith Chart many times for various RF problems. (If I was ever going to get a tattoo…) It’s quite elegant but really nothing more than a complex (the math real & imaginary meaning) impedance chart scaled, normalized and bent such that all values from zero to infinity can be shown. [A picture of my baby from work.](http://www.madmadscientist.com/html/ThesisImages/Image11.jpg) (Not mine exactly, but pretty close.) An [interactive Smith Chart](http://www.objetos-interactivos.es/smith/smith.html) (Flash) for anyone who wants to play with it. ---
**Author:** ![Senegoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senegoid/32/6606_2.png) [@Senegoid](https://boards.straightdope.com/u/Senegoid)\ **Post date:** [November 30, 2012, 10:39pm UTC](https://boards.straightdope.com/t/a-slide-rule-is-a-physical-instantiation-of-multiple-nomograms-t-or-f/642552/12 "2012-11-30T22:39:09Z")
I guess all the Mr. Spocks even in the 23rd century still need Jeppesen calculators in outer space to compute their wind triangles! Solar wind triangles, that is. 😃 ---
**Author:** ![jackdavinci](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackdavinci/32/3259_2.png) [@jackdavinci](https://boards.straightdope.com/u/jackdavinci)\ **Post date:** [November 30, 2012, 10:52pm UTC](https://boards.straightdope.com/t/a-slide-rule-is-a-physical-instantiation-of-multiple-nomograms-t-or-f/642552/13 "2012-11-30T22:52:24Z")
Anyone else have trouble writing about nomograms without constantly accidentally typing “monograms”? 🙂 ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [December 1, 2012, 12:07am UTC](https://boards.straightdope.com/t/a-slide-rule-is-a-physical-instantiation-of-multiple-nomograms-t-or-f/642552/14 "2012-12-01T00:07:05Z")
[quote=“standingwave, post:11, topic:642552”] … [A picture of my baby from work.](http://www.madmadscientist.com/html/ThesisImages/Image11.jpg) (Not mine exactly, but pretty close.)…/QUOTE] Congratulations! But I can never tell if it’s a boy or a girl until the sonograph technician points out the penis. Also, a nice rear-view traveling down and out the birth canal. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [December 1, 2012, 3:22am UTC](https://boards.straightdope.com/t/a-slide-rule-is-a-physical-instantiation-of-multiple-nomograms-t-or-f/642552/15 "2012-12-01T03:22:46Z")
Project Rho’s Antique Instruments page, including several nomogram links: [http://www.projectrho.com/antique.html](http://www.projectrho.com/antique.html) Also, from the Atomic Rockets page, Astrogation (slide rules, analog computing, etc.): [http://www.projectrho.com/public\_html/rocket/astrodeck.php](http://www.projectrho.com/public_html/rocket/astrodeck.php) ETA: old joke: ask an engineering student how much is two times two, and he’ll pull out a slide rule and after a moment say “About four”. ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [December 1, 2012, 3:14pm UTC](https://boards.straightdope.com/t/a-slide-rule-is-a-physical-instantiation-of-multiple-nomograms-t-or-f/642552/16 "2012-12-01T15:14:00Z")
> [@Lumpy](#): > > ETA: old joke: ask an engineering student how much is two times two, and he’ll pull out a slide rule and after a moment say “About four”. For sufficiently large values of 2. See [Straight Dope Message Board \> Main \> General Questions “2+2=5 for large values of 2” Huh?](http://boards.straightdope.com/sdmb/showthread.php?t=419965)