Some hoorays for the slide rule



#50

There were several threads last year which addressed the capabilities of the slide rule technology. A new book From Archangel to Senior Crown - Design and Development of the Blackbird by Peter W. Merlin of NASA published by the AIAA has some interesting comments on the state of computing technology at that time of the Blackbird development:

From page 9: "... Johnson and his team of engineers had to draw on available enabling technologies and design tools. Routine calculations were made with slide rules. More complex calculations, such as stress analysis, requuired Friden mechanical calculators. The most advanced computer available at the time was the IBM mainframe. ..."

From page 154: "... Perhaps the most impressive characteristic of the Blackbirds is the fact that they were designed before the advent of supercomputing technology. A small team of talented engineers, using slide rules and know-how, built a family of operational airplanes capable of flying faster and higher than any airbreathing craft before or since. ..."

From page 158: "... Although Pratt and Whitney had a very large computer system for its day it was no more sophisticated than some of the hand-held calculators that became available within two decades. Consequently, like the Blackbirds it powered, the J58 was essentially designed by slide rule.

We did have Fridens both at Honeywell and at Area 51. A few of the Fridens even had the square root capability. For trig funcions we had some truncated series but more often than not used lookup tables. In the olden days we carried our log log duplex decitrig on our belt and our Chemical Rubber book of log and trig tables under our arm.

Palmer


#51

Quote:
In the olden days we carried our log log duplex decitrig on our belt and our Chemical Rubber book of log and trig tables under our arm.
Went to physics lab this way in my 2nd year at university (just with a less powerful slide rule). Then came the calcs ...

#52

How are you doing? I guess you are retired and almost a hundred years old...?


#53

He, even I used a slide rule in my early days and I'm not even half a century!


#54

Did you also carry the log-tables?


#55

No, I wasn't that much of a nerd. I left them on my desk!:-)

Seriously though, log tables were obsolete--that's what the slide rule was for....


#56

Well, this is certainly one the largest group of people that I know that understand the old, classic tale/math pun. Generally when I try to relate the joke, I get blank stares. But... since I didn't find that it was ever posted in the forum, and given the topic.... I couldn't resist the opportunity:

"When the waters of the Flood subsided, Noah spake unto the animals: "Go forth and multiply." All the animals did as they were bid, save a pair of serpents, who said, "We cannot multiply, for we are adders." Then Noah bade them, "Come thou hither, upon the rough furniture where I partake my meals." They did so, and in due time, became exceeding numerous, for even adders can multiply with a log table."

Well, I still think it's funny, anyway. <sigh>


#57

Ooof, that's a very nice one, though it brought me next to the limits of my English d;-)

#58

I love Rowan Atkinson's "Black Adder" series. Can you see Brian Blessed playing Noah, and Rowan playing the adder? I'm in stitches just thinking of it!

#59

Quote:
Seriously though, log tables were obsolete--that's what the slide rule was for....

Not always. In applications that required more than three digits we could use the log tables and the log trig tables and use addition on a pad of paper followed by taking the antilog for the answer. But it was slow going since we also typically had to interpolate from the tables.

And even where we had machines like the Fridens we needed the trig tables unless we wanted to calculate each trig function as we needed it. Looking it up in the table was a lot faster.

And, now for a different use for a slide rule. A few years ago I was about to purchase a Post Mannheim slide rule at a garage sale. Another individual asked to look at it and commented that without it he never would have passed physics class. I commented on it's calculating capability and he responded "Oh no! I had trouble remembering all those formulas until I found that I could write them in the well under the slide."

Of course, that couldn't be done with a duplex rule. And it couldn't be done with the rules which had additional scales in the well. One of the most unique of the scales in the well allowed the rule to be used as an inside caliper.

Palmer


#60

[quote]And, now for a different use for a slide rule. /quote]

Here's another great use: I like to use the slide as a nifty straight edge for drawing lines. Because the ridges stuck out on the side, you can draw a line with your ink pen (we used those before ball points!) and not worry about the ink wicking up under the ruler.

#61

You guys ACTUALLY CARRIED AROUND the CRC Handbook or CRC Math Tables??!! I wouldn't want to arm wrestle you gentlemen!

I thought a HP-34C was heavy enough...


#62

Ed, I don't want to demolish your illusion, but my table book was less than 1cm thick that time d:-)

#63

Of couse we carried them! :)

The slide rule hung from the belt, so it was no problem.

I just pulled out my well used copy of the CRC Standard Mathematical Tables - It's the 21st Edition, 1973. This was the one I bought to replace my 1966 edition that was used in college.

I do remember (not too fondly) taking exams at Purdue University in the Elliot Hall of Music. We were issued a "lap board" that we'd take to the Music Hall and then balance it on our lap, along with the test papers, slide rule, pencils, erasers, etc. Not a fun way to take a final exam.

I learned to use a slide rule in my 9th grade Chemistry class in High School. The teacher gave each of us a cheap, simple, wooded slide rule, and gave a fairly intensive instruction on how it worked and how we should use it. To encourage its use, he made sure the test questions had to be answered to enough numbe of digits such that it would be very difficult to complete the test without the use of the rule. I was very thankful to him when I went to college, since I had already had several years of slide rule experience.

I also think the experience has really helped me in doing quick back of envelope calculations.

Bill

#64

Well, some of them probably carried the Log Tables around in their heads...

B^)

(I'm sort of remembering Richard Feynman writing that he memorized
squares and cubes and roots to make "guesses" more accurate)

Ren

dona nobis pacem

#65

I'm glad I got a little taste of slide rules in college, before I bought my HP-21.

My first was plastic, then I found a Post Versalog on clearance. (It had actually been part of a display which had been dismantled -- it's got a small hole in one end where, I think, a chain had been attached.)

My math professor used to say (after the advent of the LED calculator -- he used an HP-21) that the main drawback of a slide rule was that "it requires an external light source".

;-)


#66

Yes, but so do LCD calculators!


#67

Quote:
My math professor ... he used an HP-21 ... main drawback of a slide rule was that "it requires an external light source".


Quote:
Yes, but so do LCD calculators!

This is why the good professor used the 21! And this is why I want a NEW HP with red LEDs with a battery life of two years. And a slide rule with internal light source ;-)


#68

Quote:
And a slide rule with internal light source

Let it glow, let it glow, let it glow! d;-)

#69

some radioactivity, phosphorus, fireflies, ...

#70

Quote:
And this is why I want a NEW HP with red LEDs with a battery life of two years.

Dream on. I would settle for a backlit LCD. All cell phones have them. Sure, the battery would have to be bigger or replaced more frequently (wouldn't it be worth it?), but the calculator could have auto-off and user option to turn off backlit feature.


#71

I recall when EE's were in classes with ME's we were finished with our tests while they were still looking at their rules in confusion. An ME that I knew had an HP-35 was carrying a huge book of tables, I asked him what he was doing with that huge tome, I'm retiring it to the archives.
I remember the K&E log-log duplex decitrig rules and the P&E aluminum rules that used castor oil lube. The big guns had 20 inch rules. I never carried it on a belt, I had a briefcase, but the HP-35 went in the shirt pocket. A colleague got an HP-35 on a project and soon came to me as his battery would only last 15 minutes. I asked what the book said to do, run it flat and charge it, he had used it so little the cells were flat. My charge lasted longer and longer as I used it. My HP 65 would last 3.5 hours. Sam

#72

Quote:
Dream on. I would settle for a backlit LCD. All cell phones have them. Sure, the battery would have to be bigger or replaced more frequently (wouldn't it be worth it?), but the calculator could have auto-off and user option to turn off backlit feature.

Other than lacking a physical keyboard (which is a rather BIG "other than"!), would an iPhone (or an iPod Touch) running an HP calculator emulation app work for you?


#73

Color LCDs are practically useless without the backlight. B&W graphics LCDs are a little better, but some here have still complained about ones like you find on graphing calculators. A high-duty-cycle non-color LCD with only one or two lines can have a very bold black-on-white contrast that is readable from low light to direct sunlight. The HP-41 had one such LCD. Unfortunately consumer-oriented products have over-used color and graphics. Our bank's ATMs are another good example. When the sun is low and shining right on them, they're nearly useless. What they had before was much better, but the bank wanted to be able to have full-color advertising on the ATM.

I taught myself the slide rule in 7th or 8th grade in the early 70's and kept using it in high school and college when everyone else was on calculators. They thought slide rules were slow until they'd see a demonstration from someone who was proficient at it. I didn't get a calculator until I needed something programmable.

#74

Quote:
Other than lacking a physical keyboard (which is a rather BIG "other than"!), would an iPhone (or an iPod Touch) running an HP calculator emulation app work for you?

'Fraid not. As long as my "real" calculators still work, I will still use them. Too "old fashioned", I guess. To me a phone is a phone, and a calculator is a calculator. My cell phone is just that; I don't even use it for text messages. I keep an HP 20s in my truck so I will not have to even use the calculator application on my cell phone.

Oh, and yes, I still own two slide rules, but don't use them, because I have HP's. However, I will not give them up. You never know when you might need one ...

#75

--(after) Captain Zener

#76

At the same time I was learning algol W on the mainframe with punch cards. The 1460 pictured here was replaced by a LLoyds 333 green flourescent display (still have that baby and it works but takes 7 seconds to do a tan).

The LLoyds was displaced by an HP 25 followed by the 41C. By the time post grad was done I walked out with the 41CX and many HPIL products.

And yes my little sin/log book was given to me by my dad and it was he who taught me the slide rule on hi 4.5 inch Hemi! He also gave me the book of tables. I have it somewhere and it measured 8" by 5" by .3" thick.

Cheers, Geoff (just turned 51)

Edited: 8 Jan 2009, 1:33 p.m.


#77

Picked up this Pickett in Phoenix, Arizona at an antiques mall for $30 USd in 2001.

NOS, slide rule was still in it's plastic bag and never been used! You can see the reference to the early Apollo missions. These were carried by each crew member!

Enjoy the pictures:

They even supplied extra screws and an glass cursor!




Edited: 8 Jan 2009, 2:29 p.m.


#78

I bought a new old stock Pickett N-600ES just like yours (but without the Apollo marketing stuff on the box) from a seller on the big auction site a year or two ago. That was about the time I realized I needed glasses for the first time in my life!

It was pricier than yours ($50?), but I also picked up three 10 inch N-500ES rules in their original plastic bags (no boxes) for $15/ea. in a side deal from the same seller. Two are for my kids when they are old enough, and one is for me when my sight really starts to go.

I missed the slipstick era by a few years, so this isn't nostalgia for me. There's just something cool about how a slide rule forces you to understand what you're doing at a very basic level, and how many operations give you a range of answers instead of just a single answer with huge and useless amounts of precision.

My light calculating needs are mostly met by a recent vintage HP-12C and a HP-33S, so I haven't had much call for the rules other than expanding my mind a little.

#79

Thank you for the heads-up on the new book. I have several books on the SR-71 Blackbird (and its predecessor the A12) but none that cover its design in depth. I am so getting this book.

From aircraft to spacecraft and calculators I am constantly amazed at what engineers were able to design and built with the extremely limited tools they had access to. It is still unbelievable in my mind that you could design a spacecraft that could land on the moon largely with engineers using slide rules and look-up tables! As an electrical engineer I now have access to an array of complex engineering tools that allow me to design systems that I could never have done by myself using the pencil, velum and simple logic integrated circuits that I used in the mid 80's when I started design work.

I missed the slide rule era by only a few years. I sometimes regret that I didn't get to use one but I did get the witness the exciting dawn of hand calculators and the amazing design work at HP. And I did get to wear an HP-25 on my belt in high school! (Maybe I shouldn't say that too loud, it kind of leaves a weird image in some people's head)
I bought a Pickett slide rule at a yard sale a few years ago and learned to use it just for the challenge. My opinion is that it is much easier to go from using a slide rule to a calculator than vice versa! I did get to write FORTRAN programs using punch cards just before they retired them at my college (1983!).

The slide rule. An elegant tool from a more civilized time.


#80

Steve:

You wrote:

Quote:
My opinion is that it is much easier to go from using a slide rule to a calculator than vice versa! I did get to write FORTRAN programs using punch cards just before they retired them at my college (1983!).

Learning the basics of slide rule operation in the old days was easy because it was simply an extension of the use of logarithm tables for multiplication. The Chemical Rubber book had tables for both the trig functions and the logarithms of the trig functions.

I worked with punch cards when doing Fortran programming on a Sigma 5. The discarded boxes could be used to organize stuff for storage. I still have some of them. But, my best use of the boxes was when I was teaching Sunday school. I picked up a couple of hundred discarded boxes from Honeywell. The kids built a wall with them and took turns knocking down the wall as others circled the wall singing "Joshua fought the battle of Jericho".

Palmer

#81

The following is a file I saved off the 'net many years ago.

Unfortunately, back then I trimmed the header and lost information about who authored it.

Ren

dona nobis pacem

Reasons Why a Slide Rule (and Paper Pad) is Better Than an X Workstation

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

- A Slide Rule doesn't shut down abruptly when it gets too hot.

- One hundred people all using Slide Rules and Paper Pads do not
start wailing and screaming due to a single-point failure.

- A Slide Rule doesn't smoke whenever the power supply hiccups.

- A Slide Rule doesn't care if you smoke, or hiccup.

- You can spill coffee on a Slide Rule; you can use a Slide Rule
while _completely_submerged_ in coffee.

- You never get nasty system messages about filling up your entire
paper quota with pointless GIF pictures for the root window.

- A Slide Rule and Paper Pad fit in a briefcase with space left over
for lunch or a change of underwear.

- A properly used Slide Rule can perform pipelined *and* parallel
operations. (Okay, you need a guru for this.)

- You don't get junk mail offering pricey software upgrades that
fix current floating point errors while introducing new ones.

- A Slide Rule doesn't need scheduled hardware maintenance.

- A Paper Pad supports text and graphics images easily, and can be
easily upgraded from monochrome to color.

- Slide Rules are designed to a standardized, open architecture.

- You can hold a Slide Rule at arm's length, to hit the obnoxious
person at the next seat over.

- a Slide Rule is immune to viruses, worms, and other depradations
from hostile adolescents with telephones.

- Additional Paper Pads can be integrated into the system seamlessly
and without needing to reconfigure everything.

- Nobody will make you feel bad by introducing a smaller, faster,
cheaper slide rule next month.

from the frustrated, system-crashed desk of bob,mon.


#82

Quote:
- You can spill coffee on a Slide Rule; you can use a Slide Rule
while _completely_submerged_ in coffee.

That is true with the all-plastic slide rules which were available in the later years. But, if you got coffee or any other kind of water-based fluid on your low-cost rule with paint on a pine base or your K&E log log duplex decitrig with plastic on a mahogany (I think) base then you had better dry it off quickly before the wood would swell. And if you had one of the early Pickett's with a metal base then you had better dry it off quickly and very thoroughly or the next time you removed it from the case corrosion would have frozen the slide in the frame.

Palmer


#83

So, the Really Old had wooden slide rules...or stone


#84

Hyvää päivää, Veli-Pekka,

the oldest Suomen large scale slide rules, I persume, were massive rocks with ice sliding through, with one rune scale on the rock and another one on the glacier. Wooden slide rules were invented far later. Go Suomasta for log pioneer works d;-)


#85

the slide rules started to rule when someone misunderstood what a log table means...so soon one log in the middle of the table was carved with a log scale and you sifted the log then adding the two numbers produced a multiplication, Much later a shrink followed and the huge log tables were replaced by boards made of three - well - boards. This was invented by a board of scientist close to the border of mexico. Later yet another scale shrink happened, no, not the log scale - it was still used but the media became smaller and laths or bars were used - I think that was invented in a bar with a lot of lather involved somehow. Because of the Less Law, less material was used and sticks was the next step of downscaling or feature shrink, while actually more features were added in addition to the log scale adding. The scales finally proved the Rule: you could Slide it into your Pocket, so the first Pocket Slide Rule replace the old log tables...


#86

Then came the slide rules where the scales, 40 or 50 feet long, were wrapped around the log:


#87

I really like the circular ones:

Especially when traveling. You won't hear on the airplane:
"Please turn off all SLIDE RULES until 10 min. after take off"

Also slides are solar powered during the day, but can still be read with night vision goggles without problem.




#88

Hi Allen,

I agree - the circular ones are nice. I have the same one you show. Hard to tell which insert you have. I have three different inserts - CE, ST, and EE.

I think I picked mine up when the company I was working for had offered them as free giveaways at a conference. The inserts are great references.

Bill


#89

Believe it or not, the Concise Circular Slide Rule Company in Japan (which has making circular slide rules since 1954) is still open for business.

Prices range from 1,000 to 3,000 yen, or about $11 to $33, plus shipping. I've ordered a few pieces from them. In my experience, their prices are reasonable, their service (by email) is great, and their shipping is fast.

Concise is probably the last "real" slide rule company in business. Where else can you get a brand-new current model slide rule in the 21st Century?


Edited: 13 Jan 2009, 2:52 p.m.

#90

Napier's bones?

#91

Palmer --

Thank you for posting of the new literature for the SR-71 Blackbird, which was way ahead of its time in 1959.

In my own line of work, I like to note that the Amercian marvels of civil and electrical engineering Grand Coulee Dam (1942) and Hoover Dam (1936) were designed using the same rudimentary computing aids -- slide rules and tables -- but no Friden. Let's also not forget the Golden Gate Bridge (1937).

These successful undertakings were made possible by solid knowledge of fundamentals, good engineering judgement, and time-honored know-how. Too often today, "analysis paralysis" -- driven by political interference and the accessibility of computer-assisted simulation -- slows the wheels of progress to a grinding halt.

-- KS

Edited: 12 Jan 2009, 1:03 a.m.


#92

All the great medieval cathedrals were build without slide rules or calculators. The builders relied heavily on their forefather's experience and intuition (see Ken Follett's Pillars of the Earth). Before and after them, many astounding buildings were erected without what we would call scientific groundwork. Roman aqueducts, pyramids, the Versailles water fountain system...


#93

For the pyramids, at least, it is known one very old was constructed "experimentally". It's the Bent Pyramid. Nearly 4000 (!) years later, in medieval cathedrals, the same process is reported having happened some times still. "Progress is a snail." (Günther Grass)

#94

Quote:
All the great medieval cathedrals were build without slide rules or calculators. The builders relied heavily on their forefather's experience and intuition (see Ken Follett's Pillars of the Earth). Before and after them, many astounding buildings were erected without what we would call scientific groundwork. Roman aqueducts, pyramids, the Versailles water fountain system...

I must disagree. The ancients built using scientific knowledge that in fact served as the "groundwork" for modern science.

Shall I mention Pythagoras, Hero, Archimedes, Euclid, to name just a few?


#95

Quote:
Pythagoras, Hero, Archimedes, Euclid

These guys are pre-medieval, for sure. They contributed important ideas. Structural analysis however started after the Middle Ages with Leonardo as its earliest contributor. Before that, medieval builders could not calculate forces and structures. They only build the structure another master builder had constructed before and varied it a little to their liking, thus eventually finding new possibilities in an experimental kind of way.


#96

Quote:


Structural analysis[/link] however started after the Middle Ages with Leonardo as its earliest contributor. Before that, medieval builders could not calculate forces and structures. They only build the structure another master builder had constructed before and varied it a little to their liking, thus eventually finding new possibilities in an experimental kind of way.


I was referring to Walter's comment about design of ancient structures, not Middle Ages. [:-)


#97

Quote:
I was referring to Walter's comment about design of ancient structures, not Middle Ages.

Nice trick, but hardly believable. You quoted George's post and responded to this d:-)

Anyway, dropping the names of some exceptional folks living over 2000 years after Snofru doesn't really hit, since I didn't mention this time. Most of their work was forgotten in the centuries I was talking about. In general, my argumentation is on line with George's.

#98

Spirit of St. Louis another good example


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