(more than 200 in number) includes an Opera, 'Floris de Namur,' successfully performed at Wiesbaden; a grand Mass, 'St. Philip de Neri'; Overtures ('Macbeth' and 'Rübezahl'); Trios for harp, violin, and violoncello; a Concertino for harp and orchestra; 'Loreley'—a legend for harp and orchestra; a Quartet for 4 harps, etc.
OBLIQUE PIANO. A cottage pianoforte the strings of which are disposed diagonally, instead of vertically as is usual in upright instruments. The greatest angle however is at the longest and lowest string: the bias gradually diminishing until the shortest and highest string is vertical or nearly so. The object is to get greater length in the bass strings. The invention of the Oblique Piano is due to Robert Wornum, of London, who, in 1811, took out a patent for an upright piano with the strings set diagonally, and the heads of the hammers in the same rake as the strings. The Oblique Piano was comparatively early adopted in France, especially by Messrs. Roller & Blanchet, who made very distinguished small instruments in this manner. The principle has since been generally adopted by the best French and English makers, and more recently by the Germans and Americans. [See Pianoforte.]
OBOE (Fr. Hautbois; Ger. Hoboe, Hochholz). A wooden reed instrument of two-foot tone, borrowing one or two semitones from the four-foot octave. It is played with a double reed, although it is possible to produce all its scale with a single-reed mouthpiece somewhat similar to that of the clarinet. It is of the highest antiquity, and in one form or another is used in all parts of the globe. It can be traced in the sculptures and paintings of ancient Egypt and Greece; indeed, specimens are preserved in the British and Leyden Museums, which were found with straws beside them, probably to be used in making the reed. Instruments from Arabia, ancient America, China, Hindostan, Italy, and Wallachia are deposited in the South Kensington Museum. It occurs under many names in the older writers, such as Schalmei, Schalmey, Chalumeau, and Shawm. There was also a family of instruments named Bombardi, of which the Oboe was the treble. This name was corrupted into Pommer in Germany, the Bassoon being named Brummer.
Many kinds of Oboe were known in the 17th century, and are named in Bach's scores. [See O. d'Amore; O. di Caccia.] There is evidence to the effect that in 1727 Hoffmann added the G♯ and B keys. It had been used for military purposes long before it was introduced into church and secular music. Indeed, military bands were in Germany termed 'Hautboisten,' and a wellknown copper-plate engraving of the 18th century shows the band of the English Guards passing to St. James's Palace, consisting principally of oboes of different sizes, with bassoons of primitive shape, drums, and cymbals.
At the present day it is usually made in three pieces, a top, bottom, and bell joints, to which is added a short metal tube, the staple, on which the reed, consisting of two blades of thin cane, is attached by means of silk. It is essentially an octave instrument, like the flute and bassoon, with a conical bore enlarging downwards, thus differing from the flute; and without the extra joint which carries the scale of the bassoon down several tones below its natural tonic. It is understood to stand in the key of C, and is always written for in the G or treble clef. B♭ oboes are occasionally used in military bands, by way of reducing the number of flats in the signature. These require the same transposition of the written parts a whole tone higher, as is habitually practised with the B♭ clarinet. An E♭ soprano oboe, resembling the corresponding clarinet, is not uncommon, and is known under the name of the Musette or Pastoral Oboe. There is slight confusion in this name between the oboe proper and a similar instrument of the bagpipe family. It, of course, has to be written for a minor third lower than the corresponding note on the scale of C. With the exception however of the now almost obsolete Oboe d'amore, oboes in C are invariably employed in orchestral music. It will be seen elsewhere that the Oboe da Caccia was rather a modification of the bass oboe, bassoon, or brummer, than of the treble instrument, and that it corresponded to the forgotten Chalumeau, which figures in the scores of Gluck. The harmonics of the oboe, like those of conical instruments generally, are consecutive, and similar to those of an open organ-pipe. Its extreme compass, excluding the low B♭—not present in many instruments, and only occasionally needed, as in the Intermezzo of Mendelssohn's Midsummer Night's Dream music—is of two octaves and a fifth, from the B♭ or B♮ below the treble stave; or even two semitones higher, the last three or four upper notes being difficult to produce and ineffective in combination. In consequence of its peculiar and somewhat strident tone, it is not well adapted to rapid or arpeggio passages, although a long and difficult solo of this character has been allotted to it in the Benedictus of the Mass known as 'Mozart No. 12,' extending to the upper E♭, very little below the extreme compass of the instrument.
The fingering in the older and less complicated specimens is not dissimilar from that of the flute and bassoon, the latter of which is its natural bass. From the lowest note, whether B♭ or B♮ (1), to the B♮ next above (2), thirteen or fourteen consecutive semitones are successively obtained by lifting fingers or depressing keys, those of the lowest C and C♯ being very unnecessarily transposed. The next C (3) resembles that of the flute in its cross fingering by lifting the forefinger, and keeping the middle finger of the left hand pressed down, or the upper F of the bassoon in adding to this a depression of the three first fingers of the right hand also. The top orifice remains open or half stopped, for the C♯, D, and E♭. E♮ (4) is produced by closing this and the other left-hand orifices, as well as the first two for the right, and pinching the embouchure with
