1) Whewell is not coining the term, but claiming it was proposed by "some ingenious gentleman" during previous (1833 meeting?) discussion - was this perhaps sarcastic self-reference? More importantly he suggests it was discarded at the time.
2) More broadly while this comes up in the discussion of what exactly they should call what we now refer to as scientists, it is as an aside in discussion of Mary Somerville's work.
It seems then that the term was neither coined by Whewell, nor was it coined directly after Mary Somerville. Rather it was (first?) recorded in use here by Whewell, picked up again in explict discussion of Somerville as an exemplar.
If correct I guess this makes most arguments here sort-of right, unless there is an earlier written source?