The Slide Rule
That IBM ad at the end is priceless on so many levels.  
(What did that massive computer do? How many female engineers do you count... etc,)<p>Thanks for the article. My grandfather was an accountant who preferred the slide rule to a calculator. I grew up with slide rules around me, and never could understand the logic.<p>Another tool lost in the past generation is the Abacus (here is a great story with Feynman[1]) and I would love more info as to how those compared in logic or use, if anyone can shed insight.<p>[1]: <a href="https://www.ee.ryerson.ca/~elf/abacus/feynman.html" rel="nofollow">https://www.ee.ryerson.ca/~elf/abacus/feynman.html</a>