Hi, Joe - The song is in The Irish Songbook by the Clancys. title shown is "Mr. Moses Ri-Tooral-i-ay." Attribution is "Adapted by Pat, Tom, and Liam Clancy, and Tommy Makem." The Harry Fox Agency's songfile.com also attributes the song to the Clancys. Note that the Digital Tradition attributes the song to "Brain O'Higgins," so I don't know it the Clancys, the DT, or both are wrong on attribution (and I imagine that's Brian O'Higgins, who wrote "The Soldiers of Cumann Na mBan" and other Irish songs). Here are the background notes from the Clancy songbook:

At one time the Irish language, Gaelic, was forbidden by British law. This is a song about a Jewish marchant who arrived in a small town and opened a store, over which he put his name in Hebrew. A very ambitious British policeman came along, took one look at the Hebrew, assumed it was Gaelic, and dragged the Jew into court. That's the gist of it. It wasn't written so much to show the great love between the Irish and the Jews as to show the stupidity of the British.

The DT transcription of the song is very close to that in the clancy songbook - just a few typos in the last verse.
Can anybody give us solid verification of the songwriter's identity?
-Joe Offer-