The Lost Art of Logarithms

Charles Petzold holding massive slide rule

An online book-in-progress by
Charles Petzold
wherein is explored the utility, history,
and ubiquity of that marvelous invention,
logarithms
including what the hell they are,
with some demonstrations of their
primary historical application in
plane and spherical trigonometry.

Some paragraphs are coherent; others are not. Sometimes paragraphs are only a phrase or a note to myself. Nothing has been professionally edited.

I've been developing the pages in Edge using Visual Studio Code running under Windows 11 on a Microsoft Surface Pro 9. I've also been testing the pages in Chrome on that machine, and in Safari on a Mac Mini running Sequoia, and in Chrome (version 126, it says) on an Asus Chromebook.

However, my iPad Mini running iOS 12.5.7 has several problems with these webpages, and the pages often become quite awkward on phones.

Preface. What I'm Trying to do Here

Part I. The Book of Vlacq

Chapter 1. Logarithms? Are Those Like Algorithms?

Chapter 2. The Magic Demystified

Chapter 3. It’s Really About Trigonometry

Chapter 4. Mapping Out the Earth

Chapter 5. Reaching for the Stars

Part II. Mathematicians at Work

Chapter 6. Napier’s Life and Reformatory Times

Chapter 7. Countdown to the Apocalypse

Chapter 8. Conceiving the Logarithm

Chapter 9. Napier’s Handoff to Briggs

Chapter 10. e, Naturally

Chapter 11. Logarithms at Your Fingertips

· · ·

Part III. Logarithms Everywhere

Chapter TK. Log and Log-Log Phenomena

Chapter TK. Time and Space

Chapter TK. Sound and Music

· · ·

· · ·

Appendices

Appendix A. Calculating Manhattanhenge

Appendix B. Peter Mark Roget and the Log-Log Scale

About the Author