alt Hacker News>The point of the article is that he can set the C and D scales to the proportion he needs, one time, and then just move the slider around for each ingredient, rather than doing a different calculation for each ingredient.
Is punching a number into a calculator and then multiplying by M (memory function, for the scale factor) really that much work than carefully sliding tithe slider into position and reading/eyeballing the output?
Yeah. Heck, you can just prop the slide rule up somewhere and look at it without even moving the slider. No button punching required.