At first sight, it may appear too much to say that the Ogham alphabet was founded on the Latin alphabet. Why, let us ask, might it not have been a quite independent invention? A little reflection will convince us that it could not have been an independent invention. There is no limit, practically, to the possible varieties of alphabet, _i.e._, of graved or written symbols used to represent words. There are pictorial systems, and derived from these the so-called hieroglyphics, systems in which every word has a distinct syllable, systems in which each character stands for a symbol, systems in which no vowels are written, and systems which have distinct symbols for vowels and consonants. To the last class belong the Greek and Latin alphabets. There are systems in which the long and short vowels are distinguished, for example, in Pitman's shorthand alphabet; and this is partly the case in the Greek alphabet. The Ogham alphabet belongs to the class in which there are distinct symbols for vowels and consonants. All its consonants but one are found in the Latin alphabet. Except for this one, representing the sound of _ng_ in _song_ or _sing_, it is content with the Latin consonants, though each of them has to express two very distinct sounds in Irish, the mute or stop sound and the spirant or "aspirate" as it is popularly called. Lastly, it has the five Latin vowels, without distinction of long or short. Hence its Latin origin is hardly open to question. Until Cæsar's time, the Greek, not the Latin, alphabet was in use among the Gauls, the nearest people to Ireland by whom writing was then used. The Ogham alphabet and the Latin alphabet differ, generally speaking, in the same respects from the Greek alphabet. The latter therefore cannot have furnished the Irish model. The conclusion is that the Ogham alphabet, based on the Latin, was devised at some time later than the introduction of the Latin alphabet into neighbouring countries, that is to say, about the beginning of the Christian era or some what later. It was suitable only to the purposes for which it is known or related to have been used, _i.e._, for brief inscriptions or brief messages or statements. It was not suitable for the ordinary expression of written thought, for literature in the wide sense.