Log jams: Napier's logarithm and its morphs
The invention of logarithms in the 16th century was arguably the most valuable contribution to computational mathematics for centuries. Yet, John Napier’s original logarithm, though appropriate for his method and purposes, was significantly different from our present-day logarithms. Through important developments begun by Napier, his “best beloved friend” Henry Briggs and others, subsequent systems of logarithms began to resemble those forms of logarithms which are commonly used today. ^
History, European|Mathematics|History of Science
Kenan Walker Kelly,
"Log jams: Napier's logarithm and its morphs"
ETD Collection for Tennessee State University.