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.

Chapter 1. The 400-Year-Old Computer

Part I. The Book of Vlacq

Chapter 2. The Conquest of Multiplication

Chapter 3. The Magic Demystified

Chapter 4. Even Powers and Roots?

Chapter 5. Calculating a Logarithm by Hand

Part II. In the Service of Trigonometry

Chapter 6. The Pythagorean Breakthrough

Chapter 7. Beyond the Straight Right Triangle

Chapter 8. The Ubiquitous Sinusoid

Chapter 9. Mapping Out the Earth

Chapter 10. Reaching for the Stars

Part III. Mathematicians at Work

Chapter 11. Napier’s Life and Reformatory Times

Chapter 12. Countdown to the Apocalypse

Chapter 13. Conceiving the Logarithm

Chapter 14. The Handoff to Briggs

Chapter 15. Bones and Other Oddities

Part IV. Further Enhancements

Chapter 16. Logarithms at Your Fingertips

Chapter 17. The Natural e

Chapter 18. Peter Mark Roget and the Log-Log Scale

Part V. Logarithms Everywhere

Chapter 19. Log and Log-Log Phenomena

Chapter 20. Time and Space

Chapter 21. Sound and Music

· · ·

· · ·

Back Matter

About the Author