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Really impressed by the international slide rules museum
05-27-2018, 09:09 PM
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RE: Really impressed by the international slide rules museum
Perusing the slide rule museum my eye caught the title of a book " The Slide Rule and Its Use in Problem Solving" that is available as pdf.

I am impressed. Maybe I set the expectation too low for the slide rule and related documentation. Nonetheless the book is barely mentioned in google scholar (that is neat to keep a library of interesting books/articles) or goodreads (that is neat to keep track of books. I should open a thread asking for goodreads lists or the like).

Giving it a quick sample read I observe that:
- the book describes quite some uses of slide rules. Those tools were quite well done! Impressive. I knew that they used logarithms to speed up multiplication and divisions, but then they did scales for a lot more, even complex numbers or triangles. Although the book doesn't always explain why some scales or procedures work (the math behind them). Sometimes it is not that immediate to see what is the math relation behind some choices, like inverted scales that can be used for multiplication too.
- the part of problem solving is also surprisingly "fresh". I was expecting something more dogmatic or "it is this way"
- I go a better grasp why (a cheap) scientific calculator is a slide rule killer - although for some operations the slide rule would be still faster, like conversion.

Every time I see discussion about "I want more digits of accuracy" I roll my eyes, as it is unlikely that one will really need more than 3-4 decimals points (I can understand for purpose of testing or learning though). Anyway this is not true in case of large numbers. Building sections of 5435 meters each (dunno, highway or cables) is something different than 5430 meter. A section 5 meters short can ruin a costly project. Now with the slide rule, at least the standard ones, one mostly could do estimates if large numbers were involved. I wonder if then they did a second pass to compute the numbers down to the required accuracy.
A calculator, even if offering few functions, would surely be awesome in those cases (operations with large numbers) as the accuracy to 5/6 digits could be crucial.
Another point is that one had to be focused on the operations to keep track of intermediate results and to estimate correctly where to place the decimal point.

So my guess at the moment is that when prototyping or developing ideas a slide rule was enough, then something like mechanical calculators had to be used. Or maybe larger slide rules? A calculator offered the chance to avoid the second step.

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RE: Really impressed by the international slide rules museum - pier4r - 05-27-2018 09:09 PM

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