Jayne reports having used decimal logarithm first, for their ease of calculation and having tried to switch to natural logarithms with the advent of pocket calculators\. But decimal logarithms were found to be easier to grasp\.
Easier to grasp perhaps, but dangerously misleading. Increasing the likelihood of an event from 10^-100 to 10^-99 is very different and much less significant than increasing it from 10^-2 (1%) to 10^-1 (10%). I hope this is covered later in this guide.