ORCHESTRATION (Instrumentation). The art of adapting musical ideas to the varied capabilities of Stringed, Wind, Keyed, and other Instruments. [See Orchestra.]
It is scarcely possible to over-estimate the influence exercised by this branch of technical Science upon the advancement of modern Music. The modifications through which it has passed are as countless as the styles to which it has given rise: yet its history, as recorded in the Scores of the Great Masters, proves the principles upon which it is based to be as unalterable as their outward manifestation is, and always must be, variable, and subject to perpetual progress. Unaccompanied Vocal Music, however marked may be the differences existing between its individual Schools, must, perforce, remain permanently subject to the laws imposed upon it by the character of the human Voice. For Instrumental Music no permanent legislation is possible. Eveiy new Instrument introduced into the Orchestra influences, more or less, every one of its companions. Every improvement in the form, compass, quality of tone, or executive powers of the Instruments already in use, suggests new ideas to the Composer, and results in an endless variety of new combinations. To the number of such improvements there is no limit. Stringed Instruments, it is true, change but little, except in the manner of their handling. The Violin of to-day is the Violin of two centuries ago. Not so the Wind Instruments. The Trumpet now in common use differs almost as much from that with which Handel and Bach were familiar as it does from the Organ Stop to which it lends its name. The Flute, as known to Haydn and Mozart, could scarcely hold its own, except in the upper octave, against half-a-dozen Violins: the tone of its modern successor is as powerful as that of the Clarinet, and brilliant enough to make itself heard with ease through the full Orchestra; its powers of execution are almost unlimited; and, better still, it can be played perfectly in tune—which the old Flute could not. Improvements scarcely less important have been made in the Horn, the Clarinet, and the Oboe. The Trombone has suffered comparatively little change; and the Bassoon retains, substantially unaltered, the form it bore when Handel wrote for it: but these alone, among Wind Instruments, have escaped a sweeping metamorphosis since the beginning of the present century; and, remembering this, we can scarcely feel surprised that the orchestration of the 'Occasional Overture' should bear but little outward resemblance to that of the Overture to 'Tannhäuser.' Yet the bond of union subsisting even between such extremes as these is much closer than might, at first sight, be supposed. The principle is in all cases the same. The best Composers of every epoch have aimed at the same general characteristics; and experience has proved that, where these are present, no combinations can be condemned as wholly ineffective, whether they bear the stamp of true genius or not.
The most prominent characteristics of good Instrumentation are (I.) Solidity of Structure, (II.) Breadth of Tone, (III.) Boldness of Contrast, and (IV.) Variety of Colouring. We will endeavour to illustrate each of these necessary qualities by examples selected from the Scores of a few Great Masters of different periods.
I. Solidity of structure can only be obtained by careful management of the Stringed Instruments. If the part allotted to these be not complete in itself, it can never be completed by Wind Instruments. Whether written in five, four, three, or two parts, or even in unison, it must sound well, alone. This principle was thoroughly understood even as early as the close of the 16th century, when the originators of the newly-invented instrumental Schools bestowed as much care upon their Viols as their immediate predecessors had devoted to their vocal parts. For instance, the following air, from 'Le Balet comique de la Royne'—a piece written in 1581 and alluded to in the preceding article—is so arranged as to be equally complete, whether played by Viols alone or with each separate part aided by a ripieno Wind Instrument.
Le Son de la Clochette, auquel Circé sortit de son Jardin.
Handel constructed many of his finest Overtures upon this principle; and, in common with Sebastian Bach and other great Composers of the 18th century, delighted in its fine, bold, masculine effect. Later writers improved upon it by embellishing the stringed foundation with independent passages for Wind Instruments. Thus Mozart, in his Overture to 'Figaro,' first gives the well-known subject to the Violins and Basses in unison, and then repeats it, note for note, with the addition of a sustained passage for the Flute
