Calculate In the Pre-Digital Epoch, people building bridges, launching rockets, or trying to fill an inside
This! straight used manual calculators. It might’ve been a snazzy
By Robert Luhn slide rule, or a paper wheel with dials that (when properly
aligned) computed a sales commission, the proper valve fitting,
or how big a hole a 20-megaton H-bomb would make.
As one observer put it, manual
calculators like the slide rule and its kin “radically increased our
capacity to perform complex mathematical computations.
They literally enabled us to develop our modern world.” Here
are six classic calculators, ranging from the mind-blowing
to the arcane.
When people think of slide rules, they think of the classic rectangular slipstick. But many engineers, scientists, and merchants turned to this Frisbee-sized binary slide rule from Gilson (a whopping $11 with case). This was the HP calculator of its era, sporting nearly two dozen scales, from trig functions to logarithms to multiplication. But this calculator was rooted in the real world — for merchants, the Gilson could quickly compute retail pricing and add and subtract fractions. For engineers, the Gilson could compute an answer to five figures — not bad for a pre-Pentium device. As with all slide rules, your ability to estimate numbers and keep track of decimal points was key to getting the right answer. (For more calculating, go to the Slide Rule Universe at sphere.bc.ca/test/sruniverse.html.)
Images courtesy of Robert Luhn
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