Use of logarithms. Log tables, slide-rules and scientific calculators all contain values for logs, which are used to aid multiplication and division. Logarithms are mathematical functions relating numbers to the powers of a set base number such as ten. John Napier discovered the use of logarithms and published the first logarithm, or log, tables in 1614. The use of log tables was improved by the introduction of slide-rules although these have also been superseded by the use of electronic calculators.