You continue to ignore the evident fact that the English "ledger"
and French "leger" are not the same word. Since the spelling
"leger" was in use to indicate the slight lines, and since
"leger" was not used for a beam or large book, the conclusion
must be that "leger lines" is correct and "ledger lines" is using
the wrong word. *You* must prove that "leger" and "ledger" are
variations of the same word, and they obviously are not, because
accountants do not use the spelling "leger". Most of your
authorities had no idea either that there was such a French word
as "leger", or its meaning, or had enough acquaintance with music
to relate it to the Italian "leggiero". That's a pretty sorry
performance, don't you think? Regards, daveA