Yes, this is straightforward (if somewhat tedious). Avowals and Denials begins with a note:
The essays of which this book is composed are reprinted, often with slight alterations, from the Illustrated London News, by kind permission of the proprietors of that paper.
The original dates can thus be found using the British Newspaper Archive. This would ...
It does mean "except", as in "There is no happiness except when one's conduct is both virtuous and self-approving" (to restructure the sentence slightly). What Franklin means here by self-approving is explained in the next sentence: not only must one's conduct be virtuous, but it mus "bear the test of our [...] reflections upon [it]". In other words, we must ...
For completeness, I leave here the straightforward and tedious search.
Monsters and logic 6 january 1934
On Christmas that is coming 23 December 1933
On the man on the spot 26 August 1933
On Shaw and his back girl 31 December 1932
On the atheist museum 19 November 1932
On the new prudery 11 March 1933
On the return of the barbarian 5 August 1933
I note that the two authors you cite are both English writers, and so the issue you bring up deals with how the English language acquired its extensive vocabulary.
While many of the words used in writing English are words inherited from Middle English (I will refer to this as stock English), a large part of English vocabulary comes from borrowings from ...