divisible into numerous sundry parts, the string group in an orchestra may be considered as an harmonic element particularly rich in resource.
B. Wind instruments.
Wood-wind.
Apart from the varying number of players, the formation of the string group, with its five constituent parts remains constant, satisfying the demands of any orchestral full score. On the other hand the group of wood-wind instruments varies both as regards number of parts and the volume of tone at its command, and here the composer may choose at will. The group may be divided into three general classes: wood-wind instruments in pair's, in three's and in four's, (see table on page 13).
Arabic numerals denote the number of players on each instrument; roman figures, the parts (1st, 2nd etc.). Instruments which do not require additional players, but are taken over by one or the other executant in place of his usual instrument, are enclosed in brackets. As a rule the first flute, first oboe, first clarinet and first bassoon never change instruments; considering the importance of their parts it is not advisable for them to turn from one mouth-piece to another. The parts written for piccolo, bass flute, English horn, small clarinet, bass clarinet and double bassoon are taken by the second and third players in each group, who are more accustomed to using these instruments of a special nature.
| Wood-wind in pair's | Wood-wind in three's | Wood-wind in four's |
| (II—Piccolo). | (III—Piccolo). | 1 Piccolo (IV). |
| 2 Flutes I. II. | 3 Flutes I. II. III. | 3 Flutes I. II. III. |
| (II—Bass flute). | (III—Bass flute). | |
| 2 Oboes I. II. | 2 Oboes I. II. | 3 Oboes I. II. III. |
| (II—Eng. horn). | 1 Eng. horn (III). | 1 Eng. horn (IV). |
| (II—Small clarinet). | (II—Small clarinet). | |
| 2 Clarinets I. II. | 3 Clarinets I. II. III. | 3 Clarinets I. II. III. |
| (II—Bass clarinet). | (III—Bass clarinet). | 1 Bass clarinet (IV). |
| 2 Bassoons I. II. | 2 Bassoons I. II. | 3 Bassoons I. II. III. |
| 1 Double bassoon (III). | 1 Double bassoon (IV). |
The formation of the first class may be altered by the permanent addition of a piccolo part. Sometimes a composer writes for two piccolos or two Eng. horns etc. without increasing the original number of players required (in three's or four's).
Note I. Composers using the first class in the course of a big work (oratorio, opera, symphony, etc.) may introduce special instruments, called extras, for a long or short period of time; each of these instruments involves an extra player not required throughout the entire work. Meyerbeer was fond of doing this, but other composers, Glinka for example, refrain from increasing the number of performers by employing extras (Eng. horn part in Rousslân). Wagner uses all three classes in the above table (in pair's: Tannhäuser—in three's: Tristan—in four's: The Ring).
Note II. Mlada is the only work of mine involving formation by four's. Ivan the Terrible, Sadko, The Legend of Tsar Saltan, The Legend of the Invisible City of Kitesh and The Golden Cockerel all belong to the second class, and in my other works, wood-wind in pair's is used with a varying number of extras. The Christmas Night, with its two oboes, and two bassoons, three flutes and three clarinets, forms an intermediate class.
Considering the instruments it comprises, the string group offers a fair variety of colour, and contrast in compass, but this diversity of range and timbre is subtle and not easily discerned. In the wood-wind department, however, the difference in register and quality of flutes, oboes, clarinets and bassoons is striking to a degree. As a rule, wood-wind instruments are less flexible than strings; they lack the vitality and power, and are less capable of different shade of expression.
In each wind instrument I have defined the scope of greatest expression, that is to say the range in which the instrument is best qualified to achieve the various grades of tone, (forte, piano, cresc., dim., sforzando, morendo, etc.)—the register which admits of the most expressive playing, in the truest sense of the word. Outside this range, a wind instrument is more notable for richness of colour than for expression. I am probably the originator of the term "scope of greatest expression". It does not apply to the piccolo and double bassoon which represent the two extremes of the orchestral compass. They do not possess such a register and belong to the body of highly-coloured but non-expressive instruments.
The four kinds of wind instruments: flutes, oboes, clarinets and bassoons may be generally considered to be of equal power. The same cannot be said of instruments which fulfil a special purpose: piccolo, bass flute, Eng. horn, small clarinet, bass clarinet and double bassoon. Each of these instruments has four registers: low, middle, high and extremely high, each of which is characterised by certain differences of quality and power. It is difficult to define the exact limits of each register; adjacent registers almost blend together and the passage from one to another is scarcely noticeable. But when the instrument jumps from one register to another the difference in power and quality of tone is very striking.
The four families of wind instruments may be divided into two classes: a) instruments of nasal quality and dark resonance—oboes and bassoons (Eng. horn and double bassoon); and b) instruments of "chest-voice" quality and bright tone—flutes and clarinets (piccolo, bass flute, small clarinet, bass clarinet).
These characteristics of colour and resonance—expressed in too simple and rudimentary a form—are specially noticeable in the middle and upper registers. The lower register of the oboes and bassoons is thick and rough, yet still nasal in quality; the very high compass is shrill, hard and dry. The clear resonance of the flutes and clarinets acquires something nasal and dark in the lower compass; in the very high register it becomes somewhat piercing.
Note to Table B.
In the following Table B the top note in each register serves as the bottom note in the next, as the limits to each register are not defined absolutely. The note G fixes the register of flutes and oboes, C for the clarinets and bassoons. In the very high compass those notes are only given which can really be used; anything higher and not printed as actual notes are either too difficult to produce or of no artistic value. The number of sounds obtainable in the highest compass is indefinite, and depends, partly on the quality of the instrument itself, partly on the position and application of the lips. The signs