A plot of the Napierian logarithm for inputs between 0 and 108.The 19 degree pages from Napier's 1614 table of logarithms of trigonometric functions Mirifici Logarithmorum Canonis Descriptio
The term Napierian logarithm or Naperian logarithm, named after
John Napier, is often used to mean the
natural logarithm. Napier did not introduce this natural logarithmic function, although it is named after him.[1][2]
However, if it is taken to mean the "
logarithms" as originally produced by Napier, it is a function given by (in terms of the modern
natural logarithm):
The Napierian logarithm satisfies identities quite similar to the modern logarithm, such as[3]
Napierian logarithms are essentially natural logarithms with decimal points shifted 7 places rightward and with sign reversed. For instance the logarithmic values
would have the corresponding Napierian logarithms:
^Larson, Ron; Hostetler, Robert P.; Edwards, Bruce H. (2008). Essential Calculus Early Transcendental Functions. U.S.A: Richard Stratton. p. 119.
ISBN978-0-618-87918-2.