https://www.lostartoflogarithms.com/

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.

  * This is a work in progress and nowhere close to completion

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

  * It is best viewed on a desktop or laptop computer

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

Part II. In the Service of Trigonometry

Chapter 3. The Trigonometric Connection

Chapter 4. Beyond the Straight Right Triangle

Chapter 5. The Ubiquitous Sinusoid

Chapter 6. Mapping Out the Earth

Chapter 7 Reaching for the Stars

Chapter 8. Calculating Manhattanhenge

Part III. Mathematicians at Work

Chapter 9. Napier's Life and Reformatory Times

Chapter 10. Countdown to the Apocalypse

Chapter 11. Conceiving the Logarithm

Chapter 12. Napier's Handoff to Briggs

Chapter 13. e, Naturally

Chapter 14. Logarithms at Your Fingertips

Chapter 15. Peter Mark Roget and the Log-Log Scale

Part IV. Logarithms Everywhere

Chapter 16. Log and Log-Log Phenomena

Chapter 17. Time and Space

Chapter 18. Sound and Music

* * *

* * *

Back Matter

About the Author

---------------------------------------------------------------------

(c) Charles Petzold, 2025