I wasn't sure--I thought it was like the ablative--in les mots autres--perpetually happening, as you say; but I looked it up:
1.In Latin, a form of a verb used like a noun in all cases of the singular except the nominative, as "the art of singing"
2.In English, the -ing form of a verb, as doing, or a compound tense of the verb made with the -ing form of an auxilliary, as "having done", when used as the subject or object of a verb, or the object of a preposition, as doing in "Doing the work carefully is essential."--Funk and Wagnalls

Ya know what-- I forget!!!---sooo long ago--Thanks Perpetuallysad---now I dun confusing myself-----I love this thread------hugs- theo