A slide rule is more effective – much more effective – as a visual prop and tool, better than, say, a calculator, or a calculator watch, or a whipping out a smart phone to do a series of calculation. The slip stick just looks cool. Very retro-sheik, yet also allows for the human element. Perhaps that’s the problem with modern calculations.
One of my father’s old slide rules, I recall it from a time when he carried it in his shirt pocket, and I was only about half the length and circumference I am now, one of his artifacts was passed onto me while he was still alive. It’s more a curio than useful computing device.
I slipped it out of its case and ran the slide back and forth. Pie is marked. It’s a Faber-Castell from West Germany, not quite six inches long. Useful to about three points, and probably only sort of useful at that.
It took skill and a sharp eye to properly interpret a slide rule. The little hatch marks like fractions of fractions of an inch, down to a gray fuzz the lines are so fine… Those hatch marks were the answers to log, cosine, or, the best I could do? Multiply and divide. Think I’m strong enough in math skills I could still do some of this in my head, at least, to same degree of accuracy as the slide rule.
Astrology houses, I had a client trying to nail me on the exact degree of the line between houses. I recited the number. I tend to favor Koch instead of Placidus for astrology house systems, but the reason for that is purely technical. That line between houses, like the slide rule, it’s a good approximation. It’s not always the most accurate, but the numbers will be close. There’s a range.
The slide rule was good for getting within a few digits of accurate. Good for getting close. Round numbers. Big picture.
“In the ball park.”