_O_ (aw) is the fullest of the Vowel-Sounds. It is made with the mouth still farther open than when we say A (ah), and somewhat farther back; or, rather, with the cavity enlarged in all directions, and especially deepened. The mouth is stretched in all ways to its utmost capacity, giving a hollow, vacant effect to the voice, instead of the rich, mellow and substantial sound of the A (ah). The Sound so produced is, nevertheless, on the one hand, a broader quality of the A (ah), and there is a strong tendency on the part of the A (ah) to degenerate into it, as when the uneducated German, says _Yaw_ for _Ja_ (yah). On the other hand, this sound has something of the quality of O. It is, therefore, intermediate in quality between A (ah) and O. In respect to meaning, it is the Type, Analogue, Equivalent, or Representative of Volume or SPACE, whether filled or unfilled by Substance. That is to say, it is the Analogue of Space, not in the sense in which we formerly regarded Space as the _negation_ of Matter; but in the sense of _Infinite Dimensionality_, or of Dimensionality in all directions, as a vague generalization from the three special dimensions _Length_, _Breadth_, and _Thickness_. It is, therefore, round or ball-like, and huge, and, in respect to the nature of the tone, vague and vacant. Space _as mere nothing_ has no Letter-Sign in the Alphabet; but is represented by the blank types or spaces used by the printer to separate his syllables and words, as shown heretofore. Space _as a Department of Reality_, as one of the _Realities_ of the Universe, a bastard or semi-Reality it is true, but nevertheless, belonging to that Domain, is denoted by the Vowel-Sound _o_ (aw).