I??d like the nuclear half life circular slide rule.
After our big 2008 flood here, the Czech and Slovak museum was moved to higher ground.?ÿ ?ÿ We have a large population who trace to immigrants from that area.
Supposedly one of the largest buildings so moved. Here's a time lapse movie.
And a 10-minute news feature on it.
Slide rules are not typically used for addition and subtraction, but it is nevertheless possible to do so using two different (tricky) techniques.?ÿ It's amazing they were invented in 1630 and were the go to device for quick calculations until the early 1970s.?ÿ They were a great teaching tool in that you had to mentally approximate the correct answer to know where to place the decimal point.
I had a sweet bamboo slipstick in high school which I was pretty adept with but never used one for surveying, not enough significant figures.?ÿ Crazy but high quality bamboo slide rules prior to the 40s are worth hundreds and 7' long classroom rules in good shape are around $1,000 nowadays.?ÿ
The best definition of a slide rule is "logarithms on a stick".
Back when most of you were still swimmin' around in yer old mans scrotum we used to bet in Fortran lab on whose program would actually make it through the computer the size of tanker truck. That was when you filled out "lottery" cards in code. ???? ?ÿ
I had a great uncle who was a soil chemist. I have his 20" slide rule that added to precision in relative to the usual 10".?ÿ Didn't get it until I already had a scientific calculator so never really have used it. Probably very few of those around.
For real precision, there was the Fuller cylindrical slide rule, equivalent to a 40-ft rule.
https://americanhistory.si.edu/collections/search/object/nmah_694148
And the Thatcher drum slide rule, with 40-ft scales broken up into segments.?ÿ I've seen one of these, when an instrument collector and dealer (Dale) in this area had it.
https://americanhistory.si.edu/collections/search/object/nmah_1131303
I was midway through the Engineering curriculum when the simplest, 4-function handheld TI devices came out but cost more money than I had.?ÿ So, the trusty slide rule was the go to gadget.?ÿ Besides, my plastic slide rule had a capability that none of the handheld devices could provide for me.?ÿ A huge part of many engineering tests comes down to knowing a handful of magic formulae.?ÿ The plastic slide rule and an Eversharp went together like hot dogs and catsup (and mustard).?ÿ There was plenty of room to write the critical list of potential magic formulae required for a specific test somewhere on the front and back of a slide rule.?ÿ Just had to make certain I didn't get my fingers in the wrong place and smudge a key formula.?ÿ Never once did I get caught with this "aid".
My fighter pilot buddies always said "If you're not cheating, you're not trying hard enough.." Translation: "you're dying...."
@holy-cow: I just wrote the formulas I needed on the inside of my eyelids and just closed my eyes to read them when I needed one.
@holy-cow My first calculator had add, subtract, multiply, divide and a constant key.?ÿ No memory.?ÿ I drafted a plat in exchange for it.?ÿ It sure made my life easier for a while.?ÿ Then I bought my first HP (27?).?ÿ It was basically an HP25 that couldn't be programmed.?ÿ At the time the Georgia BOR would not allow programmable calculators to be used for exams.
Andy
