FRIEDRICH SAURER / SCIENCE PHOTO LIBRARY FRIEDRICH SAURER / SCIENCE PHOTO LIBRARY
Logarithmic slide rule. This adjustable ruler contains the 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. Slide-rules have been superseded by the use of electronic calculators.
Model release not required. Property release not required.