Some of your correspondents have taken up the not unnatural idea, that the last syllable of the word "Armagh" is identical with the Celtic word _magh_, a plain. But there are two objections to this. In the first place, the name is never spelt in Irish _Armagh_, nor even _Ardmagh_, but always ARDMACHA. _Ardmagh_ or _Armagh_ is only the anglicised spelling, adapted to English tongues and ears. It is therefore clearly absurd to take this corrupt form of the word as our _datum_, in the attempt to search for its etymology. Secondly, the Irish names of places which are derived from, or compounded of, _magh_, a plain, are always anglicised, _moy, moi, mow_, or _mo_, to represent the pronunciation: as Fermoy, Athmoy, Knockmoy, Moira, Moyagher, Moyaliffe (or Me-aliffe, as it is now commonly spelt), Moville, Moyarta, and thousands of other cases. And those who are acquainted with the Irish language will at once tell, by the ear, that _Armagh_, as the word is pronounced by the native peasantry, even by those who have lost that language (as most of them in that district now have), could not be a compound of _magh_, a plain. The work of M. Bullet, quoted by your correspondent "HERMES," is full of ignorant blunders similar to that which he commits, when he tells us that Armagh in compounded of "_Ar_, article, and _mag_, ville." The article, in Irish, is _An_, not _ar_; and _mag_ does not signify a town. He adopts, your readers will perceive, the modern English spelling, which could not lead to a correct result, even if M. Bullet had been acquainted with the Celtic languages. The same remark applies to the explanation given by the author of _Circles of Gomer_. _Ard_, not _Ar_, is the word to be explained; and therefore, even though _Ar_ and _Ararat_ meant, as he tells us, "earth, country, or upon and on the earth," this would throw no light on the etymology of ARD_macha_. "HIBERNICUS" (No. 14. p. 217.) is partly right and partly wrong; he adopts the anglicised spelling of the second syllable, although he seems aware that the first syllable ought to be _Ard_; and he admits also that this word is a substantive, signifying a _height_, not the adjective _high_. "A high plain," in Irish, would be, not Ardmagh, or Ardmoy (as it would have been anglicised), but _Magh-ard_ (Anglice _Moyard_). Great light will be thrown on the whole subject of the etymology of Irish typographical names, when the Index to my friend Mr. O'Donovan's edition of the _Annals of the Four Masters_ makes its appearance.