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### The Symbol for Natural Log

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Date: 06/28/2000 at 23:57:20
Subject: Natural law

Why is natural log abbreviated as "ln" and not "nl?" Please, I am just
curious.

```

```
Date: 06/29/2000 at 12:56:17
From: Doctor Rick
Subject: Re: Natural law

According to Jeff Miller's "Earliest Uses of Various Mathematical
Symbols" (which you can find from our Dr. Math FAQ page) at:

http://jeff560.tripod.com/mathsym.html

the symbol "ln" first appeared here: "ln (for natural logarithm) was
used in 1893 by Irving Stringham (1847-1909) in _Uniplanar_Algebra_."

His name doesn't sound French, but my theory is that there is a French
influence in this and other naming conventions. In French, the
modifier "natural" would follow the noun "logarithm." In the same way,
the International System of Units is called the SI, not the IS,
because in French it's Systeme International d'Unites.

French influence or not, the way we use subscripts follows the same
pattern. A subscript modifies the meaning of the main variable, and we
put it *after* the variable. For instance, Avogadro's number is called
N_A (N-subscript-A), not A_N; the A for Avogadro qualifies the N, and
it is put after the N.

This way of writing is very natural to mathematicians; it makes sense
to put the more general first, and the qualifiers or the more specific
after.

"Logarithms!"
"What KIND of logarithm?"
"Natural!"

So the notion of writing "nl" seems very odd to me, and "ln" is more
natural (no pun intended).

- Doctor Rick, The Math Forum
http://mathforum.org/dr.math/
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Associated Topics:
High School Definitions
High School Logs

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