Common logarithms
Logarithm Log"a*rithm (l[o^]g"[.a]*r[i^][th]'m), n. [Gr. lo`gos word, account, proportion + 'ariqmo`s number: cf. F. logarithme.] (Math.) One of a class of auxiliary numbers, devised by John Napier, of Merchiston, Scotland (1550-1617), to abridge arithmetical calculations, by the use of addition and subtraction in place of multiplication and division.

Note: The relation of logarithms to common numbers is that of numbers in an arithmetical series to corresponding numbers in a geometrical series, so that sums and differences of the former indicate respectively products and quotients of the latter; thus, 0 1 2 3 4 Indices or logarithms 1 10 100 1000 10,000 Numbers in geometrical progression Hence, the logarithm of any given number is the exponent of a power to which another given invariable number, called the base, must be raised in order to produce that given number. Thus, let 10 be the base, then 2 is the logarithm of 100, because 10^{2} = 100, and 3 is the logarithm of 1,000, because 10^{3} = 1,000. [1913 Webster]

{Arithmetical complement of a logarithm}, the difference between a logarithm and the number ten.

{Binary logarithms}. See under {Binary}.

{Common logarithms}, or {Brigg's logarithms}, logarithms of which the base is 10; -- so called from Henry Briggs, who invented them.

{Gauss's logarithms}, tables of logarithms constructed for facilitating the operation of finding the logarithm of the sum of difference of two quantities from the logarithms of the quantities, one entry of those tables and two additions or subtractions answering the purpose of three entries of the common tables and one addition or subtraction. They were suggested by the celebrated German mathematician Karl Friedrich Gauss (died in 1855), and are of great service in many astronomical computations.

{Hyperbolic logarithm} or {Napierian logarithm} or {Natural logarithm}, a logarithm (devised by John Speidell, 1619) of which the base is e (2.718281828459045...); -- so called from Napier, the inventor of logarithms.

{Logistic logarithms} or {Proportional logarithms}, See under {Logistic}. [1913 Webster]

The Collaborative International Dictionary of English. 2000.

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• common logarithms — logarithms using 10 as the base (Mathematics) …   English contemporary dictionary

• Common logarithm — The common logarithm. The common logarithm is the logarithm with base 10. It is also known as the decadic logarithm, named after its base. It is indicated by log10(x), or sometimes Log(x) with a capital L (however, this notation is ambiguous… …   Wikipedia

• Binary logarithms — Logarithm Log a*rithm (l[o^]g [.a]*r[i^][th] m), n. [Gr. lo gos word, account, proportion + ariqmo s number: cf. F. logarithme.] (Math.) One of a class of auxiliary numbers, devised by John Napier, of Merchiston, Scotland (1550 1617), to abridge… …   The Collaborative International Dictionary of English

• Brigg's logarithms — Logarithm Log a*rithm (l[o^]g [.a]*r[i^][th] m), n. [Gr. lo gos word, account, proportion + ariqmo s number: cf. F. logarithme.] (Math.) One of a class of auxiliary numbers, devised by John Napier, of Merchiston, Scotland (1550 1617), to abridge… …   The Collaborative International Dictionary of English

• Gauss's logarithms — Logarithm Log a*rithm (l[o^]g [.a]*r[i^][th] m), n. [Gr. lo gos word, account, proportion + ariqmo s number: cf. F. logarithme.] (Math.) One of a class of auxiliary numbers, devised by John Napier, of Merchiston, Scotland (1550 1617), to abridge… …   The Collaborative International Dictionary of English

• Logistic logarithms — Logarithm Log a*rithm (l[o^]g [.a]*r[i^][th] m), n. [Gr. lo gos word, account, proportion + ariqmo s number: cf. F. logarithme.] (Math.) One of a class of auxiliary numbers, devised by John Napier, of Merchiston, Scotland (1550 1617), to abridge… …   The Collaborative International Dictionary of English

• Proportional logarithms — Logarithm Log a*rithm (l[o^]g [.a]*r[i^][th] m), n. [Gr. lo gos word, account, proportion + ariqmo s number: cf. F. logarithme.] (Math.) One of a class of auxiliary numbers, devised by John Napier, of Merchiston, Scotland (1550 1617), to abridge… …   The Collaborative International Dictionary of English

• Binary logarithms — Binary Bi na*ry, a. [L. binarius, fr. bini two by two, two at a time, fr. root of bis twice; akin to E. two: cf. F. binaire.] Compounded or consisting of two things or parts; characterized by two (things). [1913 Webster] {Binary arithmetic}, that …   The Collaborative International Dictionary of English

• Na|pier|i|an logarithms — «nuh PIHR ee uhn», 1. natural logarithms. 2. an early system of logarithms which formed the basis for natural and common logarithms. ╂[< John Napier, 1550 1617, a Scottish mathematician, who invented the system + ian] …   Useful english dictionary

• Logarithm — The graph of the logarithm to base 2 crosses the x axis (horizontal axis) at 1 and passes through the points with coordinates (2, 1), (4, 2), and (8, 3) …   Wikipedia