One issue that has not been mentioned (and should be considered, especially if we are going as far back as 1800) is that we might be dealing with a translation from the Irish language. I'm afraid I don't have a whole lot of light to cast on this issue, but I did find some interesting information in O'Neill's Music of Ireland, Eighteen hundred and Fifty Melodies.

He lists 3 airs or songs starting with "The Humors of..."
20 double jigs
1 slip jig
4 reels
3 hornpipes

He also lists the names of his tunes in English and in Irish, and in every one of the 20 or so that I checked (by finding where the tune is printed--and the only place its Irish name is listed), in every case the Irish word is "sugra" which means playing, sporting, or fun.

I don't know if the names of these tunes originated in the Irish or in English (possibly some in each) or which way the translations went in O'Neill's collection, or even who did the translating. Sugra might well be a translation from the English. Even if it is a translation from the English, though, it does give a slightly different light to the meaning of "humour."

So, although this is not very authoritative, humo(u)rs, in this usage, might more aptly mean the "joys" of this place, or the "light-heartedness" of that place.

David Ingerson