For those intrigued by this kind of thing, this book (paper only, but the web page has more resources) may be interesting: Dead Reckoning: Calculating Without

For those intrigued by this kind of thing, this book (paper only, but the web page has more resources) may be interesting: Dead Reckoning: Calculating Without Instruments, by Ronald W. Doerfler (http://www.myreckonings.com/Dead_Reckoning/Dead_Reckoning.htm http://www.myreckonings.com/Dead_Reckoning/Dead_Reckoning.ht... ) More good stuff at http://myreckonings.com/wordpress/ http://myreckonings.com/wordpress/ . The nomography posts had caught my eye a while ago, and there may be more of those coming soon. (Disclosure: I recently exchanged a couple of emails with the author, after leaving a comment on the Heaviside post which was briefly featured here.)