Logarithm table. Rows and columns of logarithms. These are numerical values used in mathematics to aid multiplication and division. A logarithm is a mathematical function relating a number to the power of a set base number, such as ten. The value of a log is obtained from the table, reducing a multiplication or division calculation to a series of subtractions or additions. John Napier discovered the use of logarithms and published the first logarithm, or log, tables in 1614. The use of log tables has now been superseded by the use of electronic calculators.