Logs and Antilogs

Abstract

ON p. 7 of NATURE of March 3 a recommendation is mentioned that when taking out the number corresponding to a logarithm a table of antilogs should be used. Assuming the usual seven-figure work, the opposite course should be followed, because the computer can then write down five figures at once and add the remaining two by means of the difference table; no addition or crossing out is required. Thus for the logarithm 0.1234567 the log table gives 1.3287 for 1234269, and 298 in the 327 difference table gives 91, so we write 1328791. Vice versa, having 1.328791, what is the logarithm? The anti-table gives 12345 at once, whilst the difference 20 gives 67, so that we write 1234567. No figure requires alteration and the work is done with a minimum of mental strain.