Produced by the United States Office of Education, this vintage film shows the operation of the slide rule with focus on the 'C' and 'D' Scales.
The slide rule, also known colloquially in the United States as a slipstick, is a mechanical analog computer. As graphical analog calculators, slide rules are closely related to nomograms, but the former are used for general calculations, whereas the latter are used for application-specific computations.
The slide rule is used primarily for multiplication and division, and also for functions such as exponents, roots, logarithms, and trigonometry, but typically not for addition or subtraction. Though similar in name and appearance to a standard ruler, the slide rule is not meant to be used for measuring length or drawing straight lines.
Slide rules exist in a diverse range of styles and generally appear in a linear or circular form with a standardized set of markings (scales) essential to performing mathematical computations. Slide rules manufactured for specialized fields such as aviation or finance typically feature additional scales that aid in calculations particular to those fields.
At its simplest, each number to be multiplied is represented by a length on a sliding ruler. As the rulers each have a logarithmic scale, it is possible to align them to read the sum of the logarithms, and hence calculate the product of the two numbers.
The Reverend William Oughtred and others developed the slide rule in the 17th century based on the emerging work on logarithms by John Napier. Before the advent of the electronic calculator, it was the most commonly used calculation tool in science and engineering.[8] The use of slide rules continued to grow through the 1950s and 1960s even as computers were being gradually introduced; but around 1974 the handheld electronic scientific calculator made them largely obsolete and most suppliers left the business.
I started college in 1974 with a slide rule, had never seen one before I got to Chemistry 101. Some kids had TI Scientific Calculators on their belts, but I couldn't afford such!
ReplyDeleteI remember trying to work sq rooys because I couldn't afford a better calculator. Then the TI-58 came out. Still cost a pretty penny but relatively 'affordable'.
DeleteI had the same problem. I started with a slide rule, and the few kids that had one thought I was really behind the times. I wrote a problem down and told someone to call "start." I beat the guy with the calculator easily. No one said a thing about my slip stick ever again. I bought a calculator when I was able, however.
DeleteI still have my old metal Pickett slide rule tucked away.
ReplyDeleteI had a metal Pickett while in the Navy before College. I later acquired my father's Arista and bought my own Nestler while in Naples Italy. The Pickett went away and I used the Nestler while standing Navigation watches. I had learned how to use on in high school and git pretty good while in the Navy. Came in handy later.
DeleteI still have the Nestler. Most of my peers had K&Es.
Studied Engineering Mechanics, graduating in ‘74. My K+E Log Log Duplex Decitrig got me up thru my junior year, but then I was able to get an HP35, which was a super upgrade. RPN forever! (I have HP15C app on my iPhone today!)
DeleteHad a K&E until I got an Hp11c, which I still have and use to this day. Always enjoyed giving it to my grandkids and having them ask "where's the equal sign?"
DeleteI actually used my slide rule recently, I killed a bug.
DeleteI collected various types of slide rules. I used them frequently until I lost most in a divorce.
ReplyDeleteI still have the e6b which I still use.
Now do the Bygrave slide rule.
Got a half dozen, from pocket to scabbard size, hanging around. Damn near wore the numbers off 'em. And I still know how to use every scale on the dual base log log Picket N600ES I carried from 10th grade thru grad school.
ReplyDeleteThey were already gone when I got to Engineering School in 82. I still use my vintage HP 15C. We need to preserve this knowledge in case of the end times. Whoever is left might have to re-engineer civilization starting out without electricity. To quote Mother Abigail in Stephen Kings "The Stand" - "civilization comes out of that little plate on the wall".
ReplyDeleteThe HP 15C was the perfect nerd calculator. HP choked when they cropped it.
DeleteHad some plastic. Bought a steel one in college. Roommate was a Kuwaiti and he bought a Texas instrument unit that had sq root and sine functions. Now they give away solar calculators with more power that those ol ti’s.
ReplyDeleteThese days I use a Casio graphing calculator with more power than the TI 59 or the HP 41. It's also better than anything TI produces now.
DeleteI still have mine from the 60s. It is specalized in that it has values for inductors and capacitors and frequency. It's my understanding that these were used extensively by NASA engineers in the 60s to do calculations that put us on the moon. It is not solar powered nor does it have batteries or yearly upgrades, yet is still fully functional. Progress comrade.
ReplyDeleteI was fortunate that in HS, I bought one of the first calculators in 1972, I believe. Right before the chemistry teacher was set to teach us how to use a sliderule.
ReplyDeleteStarted college in '68 and slide rules were the mainstay in the math and science classes. It was tough learning to keep track of the decimal point. When the TI scientific calculators came out in the early 70s a whole lot of slide rules went in the drawer for keeps.
ReplyDeleteYup. Without even moving from my chair, I can reach three of them. My bamboo Post Versatrig has been used enough for the slide to be smooth and precise. Never actually wore the leather sheath on my belt, but it keeps it safe in my desk.
ReplyDeleteI have a BA in English because of stuff like this.
ReplyDeletelol, I know what you mean. I made it to the end of CAL II and hit the wall. Gave up and went graphic arts.
DeleteIn the early 70's slide rules were common and calculators didn't start becoming common till mid 70's. By 1980 slide rules were a rare sight. By the turn of the century only old farts could even tell you what one was. Using one is a skill that's almost dead. When things go seriously south the ability to use one could be a big deal.
ReplyDeleteThe slide rule works because the C and D scale distances are logarithms of the numbers.
ReplyDeleteIf you remember how to multiply using logarithms, you just add them and then look up the number corresponding to the sum in the logarithm tables. The slide rule does the addition and the conversion by just adding the distances on the slide.
Still have my 1970 POST Versalog. Can't remember how to use it.
ReplyDeleteStill have my metal Pickett trig scale in the original leather case. It was fun whipping it out in an engineering meeting full of newbies.
ReplyDeleteI graduated high school in 79. The slide rule was standard for the students that could not afford a simple $40 TI calculator. I had a slide rule.
ReplyDeleteWhen the Chinamen stop making slide rules, I'll still have this onion on my belt. Anna stick!
ReplyDeleteMan, I have one of those Picketts (I think) but I never learned how to use it. Be pretty cool. My Dad, an architect also had an Addometer, a rotary metal mechanical calculator for adding - subtracting dimensions. That too is cool.
ReplyDeleteThe form of the slide rule we used came from a French Artillery officer named Mannheim. I bought a "Mannheim" slide rule at a drug store in Hendersonville, TN back in the 80s for 50 cents. Still have it somewhere. Took it to an engineering class in the early 90s and the students had no idea what it was.
ReplyDeleteI just inherited my Father-in-law’s from 6” Post Versalog. It inspired me to buy a 10” version, and a Versalog Slide Rule Instruction book printed in 1951. Having gone to engineering school in the early ‘80’s, I missed slide rules completely. I love how they make you think about math instead of simply dumping all the numbers into a spreadsheet. The slide rule and a revolver - all I need for the coming Zombie Apocalypse.
ReplyDeleteJackdaddy63
I still have a couple of the bamboo/plastic ones somewhere(highschool), and an E6B, which I haven't used in decades.
ReplyDelete