To independent orchestration Gluck contributed but little, but, considering the age in which he lived, none have excelled him as an interpreter, by means of the orchestra, of pathetic expression, or in the use of appropriate instrumentation, varied and rich tone-coloring. To quote from Parry's "The Art of Music," page 220: "Moreover, the expressive qualities of his admirable recitatives are very much enhanced by his way of dealing with the accompaniment. He neglected no opportunity to make use of the qualities of his orchestral instruments--as far as in him lay--to enforce and accentuate the situations, and even to intensify the passing moment of feeling implied by the dialogue. Composers were successfully developing the sense of the functions and resources of instrumentation. Even Gluck's rival, Piccini, made some very appropriate effects by using his instruments consistently with the spirit of the situations. But Gluck applied himself to the matter with far more intensity, and far more genuine perception of the characters of the instruments. Indeed it would be hardly an exaggeration to say, that he was the first composer in the world who had any genuine understanding of this very modern phase of the art. Mozart was the first to show real natural gift and genuine feeling for beautiful disposition of tone, but Gluck anticipated modern procedure in adapting his colors exactly to the mood of the situation. A good deal had been attempted already in a sort of half-hearted and formal manner, but he was the first to seize firmly on the right principles and to carry out his objects with any mastery of resources." On the other hand, "his orchestration has none of the roundness or balance or maturity of Mozart's. It is unequal and uncertain, and requires humoring in performance to make it produce the effect which is intended." Gluck relied to an excessive degree upon the string band, and his orchestral writing lacked that balance which the contemporary and sequent classicists regarded as the fundamental requirement. Notwithstanding, his instrumentation exhibits many original insignia that are worthy of record. Thus he demonstrated the dramatic power of low-written viola parts, made varied and characteristic use of the tremolo, was the first to introduce mutes into the orchestra in his "Armide," and caused the trombones to emerge from their hitherto menial subservience, and stand forth in all their dignity and tragic power of portraying peace, sorrow, fear, religion, majesty. And by proving the superior effectiveness in employing a group of three trombones, he established a precedent that has been endorsed by all subsequent composers.