OCEANICA OCTAVE. 



289 



Fuel.) The great divisions of the sea appear to be 

 inhabited by their peculiar fish, mollusca, zoophytes, 

 &c., and to be frequented by peculiar species of birds. 



The level of the seas is, generally speaking, every- 

 where the same. This arises from the equal pres- 

 sure, in every direction, which the particles of a fluid 

 exercise upon each other. The ocean, therefore, 

 considered as a whole, has a spherical or a spheroidal 

 surface, which may be considered as the true surface 

 of our planet. Exceptions to this general rule are 

 often, however, to be found in gulfs and land-locked 

 bays, where the waters become accumulated, and 

 stand higher than in the open ocean. See Islands ; 

 eee also Atlantic, Pacific, and Indian ocean, 



OCEANICA (in Malte-Brun's Geographical Sys- 

 tem); the third great division of the world, com- 

 prising all the islands which lie to the south and 

 south-east of Asia in the Pacific ocean, including the 

 Asiatic archipelago, Australia, and Polynesia. The 

 former constitute North-west Oceanica ; New Hol- 

 land, and the large islands lying round it, Central 

 Oceanica ; while the remaining islands, forming what 

 is usually called Polynesia, constitute Eastern Oce- 

 ' anica. 



OCEANIDES ; the three thousand daughters of 

 Oceanus and Tetliys. We include, under this name, 

 according to the hymns of Orpheus, the whole female 

 posterity of Oceanus, that is, all the goddesses of the 

 streams and fountains flowing beneath the earth from 

 the surrounding ocean ; only excepting from the 

 number the Nereids, or nymphs of the Mediter- 

 ranean sea, although they also, being descended from 

 Doris, one of the Oceanides, have been called by 

 Antipater of Sidon, daughters of the Ocean. 



OCEANUS ; the eldest of the Titans, whose birth 

 is connected with the origin of the sea (Pontus). He 

 was born later than Pontus, and surrounded the earth, 

 the vault of heaven sinking towards him on every 

 side. He has therefore been called the son of Gaea 

 (the earth) and of Uranus (heaven.) Oceanus and 

 Tethys were the parents of rivers, and of the race of 

 goddesses called Oceanides. According to another 

 account (see Homer's Iliad, book xiv. 201, 246,) he 

 was the father of all gods and men. He always ap- 

 pears as a peaceful god, and he took no share in the 

 mutilation of Saturn. He was not, therefore, cast 

 into Tartarus with the Titans. On account of his 

 circumspection and mildness, he was called the father 

 of wisdom. 



OCHRE. See Clay. 



OCHTERLONY, SIR DAVID, Bart., major-general 

 in the British East India company's service, was born 

 in Boston, New England, in 1758. At the age of 

 eighteen, he went to India as a cadet, and in 1778 

 was appointed ensign, and in September of the same 

 year lieutenant on the Bengal establishment. Lieu- 

 tenant Ochteiiony rose by merit through the inter- 

 vening ranks, and, in 1803, was made lieutenant- 

 colonel. In the Mahratta war of 18034, he distin- 

 guished himself on several occasions, and, after the 

 great battle of Delhi, was appointed resident at that 

 court. On the restoration of peace, he received the 

 command of the fortress of Allahabad, and, in 1809, 

 commanded a force stationed on the Sutledge, to 

 overawe the Seiks. In 1812, he was promoted to 

 the rank of colonel, and, in 1814, to that of major- 

 general. In tlie Nepaulese war he commanded a 

 division which was instructed to advance, through a 

 difficult country, against Umer Sing, a brave and 

 experienced warrior, whom he compelled to surrender 

 in the almost inaccessible fortress of Mallown. The 

 chief command was now given to general Ochter- 

 lony, who brought the war to a close, September, 

 1815, after a series of skilful operations and brilliant 

 successes. His services were rewarded, by the 

 v. 



prince regent, with the order of knight commander 

 of the Bath, and the dignity of baronet, and by the 

 East India company with a pension of 1000 per 

 annum. In 1816, Sir David Ochterlony was created 

 knight grand cross of the order of the Bath, and, in 

 1817, the thanks of the two houses of parliament 

 were voted him for his skill, valour, and perseverance 

 in the Nepaulese war. In 1817, he was invested with 

 large powers for settling the province of Rajpootana. 

 In 1818, he was appointed resident at Delhi, with 

 the command of the third division of the grand army, 

 and, in 1 822, was intrusted with the superintendence 

 of the affairs of Central India, as resident and politi- 

 cal agent in Malwah and Rajpoolana. He died in 

 1825. 



OCRACOKE INLET; an inlet of North Caro- 

 lina, forming a passage into Pamlico sound ; twenty- 

 two miles south-west of cape Hatteras ; Ion. 75 59' 

 W.j lat. 34 55' N. On each side of the channel 

 are dangerous shoals ; on the bar are fourteen feet at 

 low water. 



OCTAGON, in geometry, is a figure of eight sides 

 and angles, which, when the sides and angles are all 

 equal, is called a regular octagon, and when they 

 are not equal, an irregular octagon. 



OCTAHEDRON or OCTAEDRON ; a body con- 

 sisting of eight equal and equilateral triangles. 



OCTANT, an astronomical instrument, is the 

 eighth part of a circle, divided into degrees, and 

 used in calculating the amplitude of the stars, but is 

 now little used. 



OCTAVE, in the diatonic system of musical 

 sounds ; the eighth sound from an assumed funda- 

 mental tone. It belongs to the perfect concordant 

 intervals, so that when it is sounded with the funda- 

 mental, the ear scarcely perceives more than one 

 sound, and is hardly able to distinguish the one from 

 the other. For this reason, the octave must, in our 

 musical scale, be perfect ; whereas the other inter- 

 vals may be tuned somewhat higher or lower than 

 their true pitch. The upper octave, that is, the one 

 which is eight notes above the fundamental, is ob- 

 tained when the string which sounds it is only one 

 half as long, and the lower octave when this string 

 is twice as long, as that of the fundamental. The 

 string which sounds the upper octave in each makes 

 two vibrations, while the string of the fundamental 

 makes one. Therefore on the eighth diatonic string 

 the tone of the first, or lowest, recurs. The ninth 

 string repeats the second tone, called the second, the 

 tenth string the third tone, or the third, &c. Ac- 

 cording to the arrangement of our new or diatonic 

 system of tones, the octave is therefore the limit 

 within which the seven essential tones are kept dis- 

 tinct from each other ; and all tones without the 

 limit of the octave are only repetitions, in an aug- 

 mented or diminished degree, of the tones already 

 contained in the compass of the octave. For this 

 reason we call the octave the whole extent of the 

 tones of the diatonic system. (See Tablature.) The 

 number of upper and lower octaves, or the manner 

 in which several octaves of different heights are to 

 be chiefly distinguished, is not absolutely determined, 

 on account of the continually increasing compass of 

 instruments, particularly stringed instruments, and 

 especially the piano forte, which, within a short 

 period, has been increased a whole octave. The oc- 

 tave, considered as an interval, has, of all intervals, 

 the least harmonic effect. On this account composers, 

 when there is only one principal voice, forbid rising 

 to the octave except at the beginning or close. But 

 a succession of octaves following each other, when a 

 melody is to be raised in that manner, has a very 

 good effect. False or disallowed octaves are, in 

 musical compositions for many voices, progressions 



