Post by Jim SpriggsPost by gimmytangI am just wondering when logarithm was first used in math and how people found it.
gim
The German mathematician Michael Stifel (1486?-1567) in his
"Arithmetica
Post by Jim SpriggsIntegra" (date, anyone?) and Chuquet in his "Le Triparty en la
science
Post by Jim Spriggsdes numbres" (1484) noted that multiplication/division of terms in a
geometric progression corresponded to addition/subtraction of
exponents. Stifel noted the extension to negative exponents but did not
introduce logarithms as such.
The Scotsman John Napier (1550-1617) noted the correspondence also and
introduced logarithms (c. 1594). His concern was to ease calculation in
spherical trigonometry (essential for long sea voyages) so he
invented
Post by Jim Spriggslogarithms of sines. See his "Mirifici Logarithmorum Canonis
Descriptio" (1614).
Henry Briggs (1561-1631) suggested to Napier in 1615 that the base be
10, and he compiled the first tables of common logarithms from which
were derived the tables in use up until the appearance of the pocket
calculator.
Joost (or Jost?) B\"urgi, a Swiss watchmaker, also noted Stifel's work
and invented logarithms independently of Briggs around 1600, but his
work "Progress Tabulen" was not published until 1620.
Common logarithms are of little interest to mathematicians and have long
since lost their usefulness as a computational aid, but natural
logarithms to base e = 2.718... are important. Euler noted that one may
change base by
log_a(b) = log_c(b)/log_c(a).
Gregory of St Vincent in his "Opus Geometricum" (1647) noted (in modern
notation) that
\int_{t_0)^t dx/x = k log t .
His student Alfons A de Sarasa (1618-67) in "Solutio Problematis a
Mersenno Propositi" (1649) made a similar observation, and maybe Gregory
got the idea from his student.
Newton, around 1665, obtained
log(1 + x) = x - x^2/2 + x^3/3 - ...
where the logarithm is the natural one.
Nicholas Mercator got the same result independently in his
"Logarithmotechnia" (1668).
Let's not be too surprised if someone claims that the Hindus, or
somebody, knew all of this long before the above named were twinkles in
their fathers' eyes.
Dear John,
Thank you for your delightful coverage of logarithms, especially your
last remark. That and the fact that there were two independent
"inventors" of logarithms, made me look up John Napier. Let us see
what John Napier did apart from inventing logarithms. I copy below from
a website a description of his inventions:
While better known as a mathematician, John Napier was a busy inventor.
He proposed several military inventions including: burning mirrors that
set enemy ships on fire, special artillery that destroyed everything
within a radius of four miles, bulletproof clothing, a crude version of
a tank, and a submarine-like device. John Napier invented a hydraulic
screw with a revolving axle that lowered water levels in coal pits.
Napier also worked on agricultural innovations to improve crops with
manures and salt.
(http://inventors.about.com/od/nstartinventors/a/John_Napier.htm)
Burning mirrors and a water screw? Are they not attributed to
Archimedes?
Special artillery? Turks had been using artillery for more than a
century! (I know from Indian history that Babar used artillery when he
invaded India circa 1525.) I could not find a mention of the manure and
salt concoction anywhere but I hear fertilizers were in use in Muslim
Spain.
Now let us look at the title of John Napier's book: Mirifici
logarithmorum canonis description. Where does this word "canonis"
come from? (Some folks tell me that the word canon was a direct
"latinization" of the Arabic word "Qanoon". This indicates that
the word canon was in use and was well-understood and so Arabic books
and translations of Arabic books were well received at the time John
Napier wrote his masterpiece. (Some folks also think that
"logarithmourum" also has something to do with Algorithmi or
Al-Khwarizmi. This is all linguistic nonsense, what I want you to
concentrate on is the fact that if Archimedes stole two of John
Napier's inventions, nearly a thousand years before could it be
possible that some Muslim stole from John Napier the invention of
logarithms a few hundred years before? There is also the question of
need. Archimedes' state needed those "inventions", John
Napier's did not! The Muslims needed some kind of computation device
for their tables of trigonometric functions and of positions of stars.
The fact that they made those tables indicates that they had some such
device. What did John Napier need it for? Squat! He "invented"
logarithms to assist others in their computation.
Finally, thank you again. Before I read your post I used to get into
arguments with my Muslim friends saying, "Do not go assigning priority
to Muslims for everything" and that " the logarithm was invented by
John Napier". Now I am in doubt.
Muhammad Zafrullah