According to the opinion of Zeuss and Gluck, the DANUBE, (ant. Danubius and Danuvius, Mod. Germ. Donau,) would come in here. These writers derive it from Gael. _dan_, Ir. _dana_, fortis, audax, in reference to its strong and impetuous current. This is no doubt the most striking characteristic of the river, but it might also not inappropriately be placed to the root _tan_, to extend, whence the names of some other large rivers. Gluck considers the ending _vius_ to be simply derivative, and suggests that the Germans, with a natural striving after a meaning, altered this derivative ending into their word _ava_, _aha_, _ach_, or _au_, signifying river. Though Gluck is a writer for whose opinion I have great respect, and though this is the principle for which I myself have been all along contending, yet I am rather inclined to think that in Danuvius, as in Conovius (the Conway), there is contained a definite appellative, qualified by a prefixed adjective: this seems to me to be brought out more clearly in the Medway, and in the names connected with it. The word Ister, which, according to Zeuss, is the Thracian name of the Danube, I have elsewhere referred to the Armorican _ster_, a river. Not that I mean to infer therefrom that the name is Celtic, because _ster_ is only a particular form of an Indo-European word _sur_. If we refer the prefix _is_ to the Old Norse _isia_, proruere, then Ister would have the same meaning as that given above to Danubius. But the derivation of Mone, who explains it by _y_, the Welsh definite article, and _ster_, a river, making Ister = "The river," I hold with Gluck to be--like other derivations proceeding on the same principle--opposed to all sound philology.