A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: David Pike
Date: 2019 May 16, 09:03 -0700
Ed Popko you wrote: What is the Log+10 form of a logarithm called?
I came across this last night whilst comparing editions of Nories Tables, quite by accident, honest! The 1963 edition still used ‘add tens’ in the ‘Logs. of Trig. Functions tables, e.g. Log Sine 45 = 9.84949. In the ‘Explanation of the Tables’ section it says “In navigation tables, to avoid having to print columns of negative characteristics, it is customary to display what are called “tabular logs.” [my emboldening] Of Trig. Functions ………… Whether J. W. used that term in 1803 in his first Set of Tables, I know not.
By the 1991 revision, change was beginning to take place. An “either/or” value was given. E.g. Log. Sine 45 is now written 1.[with a bar on top](9)84949. DaveP