OCTAVE (Fr. octave, from AIL. octavo, octave, from Let. octants, eighth, from octo, Gk. OK7-6, °Ho, Skt. (wan, Lith. asztiinl, 01r. ocht, Goth. ahtdu, AS. eachta, OHG. alto, Ger. acht, Eng. eight). The interval between any musical note and its most perfect concord, which is double its pitch, and occupies the position of the eighth note from it on the diatonic scale. The name octave is often given to the eighth note itself as well as to the interval. There is between a note and its octave a far closer relation than between any other two notes; they go together almost as one musical sound. In combination, they are hardly distinguishable from one another, and their harmonics agree invariably, a coincidence which occurs in the case of no other interval. For the purpose of absolute pitch every tone is regarded as belonging to a particular series of octaves. The stave from middle C' (q.v.) to the C below is called the small octave, the next lower the great octave, because in numerical nota tion (q.v.) these tones are indicated respectively by the small and capital letters of the alphabet. The octat•e is called the contra octave. The octave from middle C upward is the one-lined octave, the next the tco•lincd octave, etc.
OCTArVIA. The sister of the Roman Emper or Augustus, and wife of Marcus Antonius. She was distinguished for her beauty. her noble dis position, and her womanly virtues. Her first hus band was C. Alareelrus, to whom she was mar ried in B.C. 50. Ile (lied in n.c. 41. shortly after
which she consented to marry Antonius, to make secure the reconciliation between him and her brother. The event was hailed with joy by all classes. In a few years forsook her for Cleopatra. When the Parthian War broke out, Octavia wished to accompany her husband. and actually went as far as Corcyra, whence Antonius sent her home, that she might not interrupt his guilty intercourse with the Egyptian Queen. in B.C. 35 Oc•tavia made an effort to rescue him from a degradation that left him indifferent even to the honor of the Roman arms, and sailed front Italy with reiinforeements; but a message reached her at Athens ordering her to return home. She proudly obeyed, but, with a magnanimity that reminds us of the Roman character in earlier and better days. she forwarded the supports to her husband. filer brother was indignant at the treatment she had received, and would have had her leave her husband's house, and come and live with him; but she refused. When, in it.c. 31, war, long inevitable, broke out between her brother and Antonius, the latter crowned his insults by sending Oetavia a notice of divorce. After her husband's death, she brought up with maternal care not only her own children, but also those of Cleopatra. Iler death took place in B.C. II. Iler son MarcyIlns (q.v.) was adopted by Augustus as his successor, hut died in B.C. 23.