a perpetual strain, they must necessarily be sometimes relieved by inferior executants; hence the necessity of an underplot, and of constructive ability to interweave this with the main action. As the musical drama is not, after all, natural, the audience's attention must be kept occupied by continual action and bustle; as the singer must leave the stage at his best, the recitative must be followed by an air. Such tags must be judged simply with reference to the musical effect, which with Metastasio was always very great. On the whole, few writers have adapted means to ends more successfully than he has done, or have more completely solved the problem of investing the amusement of the moment with abiding literary worth.
The most celebrated of Metastasio's lyrical dramas are perhaps the Olimpiade, the Achille in Sciro, the Clemenza di Tito, and the Atilio Rezolo. The Artaserse, the Temistocle, the Zenobia, have also a high reputation, and in truth the intervals of merit among his pieces are not very wide. The operatic dramatist is released from many of the obligations which press most heavily upon the tragic or comic poet; he is at liberty to mingle the manners and ideas of different ages and nations as much as he pleases; no great profundity of psychological analysis can be expected from him, for if he possessed this gift the conditions of his field of art would debar him from manifesting it. It is enough if his subject is interesting, his action lively and well combined, and his melody copious and spontaneous. Metastasio selected his themes with consummate judgment, and showed a Scribe-like power of devising bustling action and sudden surprises, while his tunefulness is remarkable even for an Italian poeu His pieces would
