The 17 Equations That Changed The Course Of History

[struggle4progress]

15. Read the translator's preface at your link: the table of so-called "hyperbolic logarithms"

at the end of the book is clearly a table of what we now call "natural logarithms" -- which do obey log(xy) = log(x) + log(y) -- but, as the translator notes, that table was not actually in Napier's original book: in fact, those logarithms were invented by others, while the table Napier himself published is the one with the sine and logarithm headings

Napier's table, unlike a table of "hyperbolic logarithms" (that is, "natural logarithms&quot , and unlike the even more convenient table of "Briggsian logarithms" (that is, "common logarithms&quot , has the unfortunate features that log(10 000 000) = 0 -- rather than the more convenient log(1) = 0 -- and that log(x) decreases with increasing x, as you can see by inspecting Table I "Napier's Logarithms of Sines," which is the table Napier himself published