I could not find the book on before the famine online, but a later one by Ignatius Murphy was at wayback
Looking for textual references to flutes in 18th century rural Ireland ... there are various flute makers listed for Dublin along with some ventures, but Dublin was not rural Ireland.
A couple of references I did find outside of that though are listed below. Actually almost all the texts available are travel writers or gentry or academic, mostly with a very limited view of rural Ireland. There are plenty to search through and not all accessible. This post
http://cstair.blogspot.com/2019/11/iris ... hy-of.html
has a good explanation on lack of use of Irish literary sources. As elsewhere at the time the rural Irish were probably relatively illiterate, and did not seem to have the foundations (library, secure dwellings etc.) for storing writings in Irish. What is available seems neglected. There must be some sympathetic middle-class accounts somewhere I should think, even if in English. Also there was repression of expression during that century.
Anyway... the two Twiss ?
So the first reference is odd, because it is a translation English traveller "Twiss" to French, and books lists it as Richard Twiss, but English books only give a known Robert Twiss writing in English to same theme, and the text of that doesn't seem to match... at least no flutes or violins mentioned (by quick search) in
https://archive.org/details/atourinirel ... /page/n164
However In
Voyage En Irlande Richard Twiss
https://books.google.pt/books?id=tz9WFf ... te&f=false
pg 176 he says the Irish much enjoyed dance, dance masters would go cabin to cabin to teach, accompanied by a flute player or a blind violin player.
Someone else might figure out the confusion.
Also in the translation of a Frenchman's walk in Ireland 1796
https://archive.org/stream/frenchmanswa ... t_djvu.txt
"I passed five or six charming days at Hazelwood. On the evening of my arrival here I was invited to a concert at Sligo It was given in the Hall of Sessions, and appeared like a complete revolution of the usual sittings. The big drum was on the Throne of Justice, the fifes and flutes in the barristers' quarters, and the audience in the place of the culprits. "
But I guess that is more town setting.
Anyway, both sort of point to flute being played before 1800 among the rural Irish, which though I take that for granted just seems to lack certainty elsewhere.