[Illustration:  Some bars of music]

The curtain rises.  It is a sultry summer night; the black woods stand round a garden; on the left is the castle of Mark, with a torch blazing at the doorway, making the surrounding night blacker.  Sounds of hunting-horns are dying away in the distance.  Brangaena and Isolda are there listening, and Brangaena, to music of enchanting beauty, is warning Isolda that the hunters can be no great way off.  “Listen to the brook,” says Isolda.  “How could I hear that if the horns were near?” Then comes one of Wagner’s matchless bits of painting—­the brook rippling through the silent night.  Isolda is now going to extinguish the torch, as a signal to Tristan that he may approach.  Brangaena protests, and warns Isolda against Melot, who has arranged this night hunt as a trap to catch Tristan; and she bewails the officiousness which led her to substitute the love-philtre for the poison.  The rest of the scene may be passed over.  The music is woven out of themes just quoted, and another which will play a big part in the love-duet: 

[Illustration:  Some bars of music]

Of course, Isolda prevails.  Brangaena is sent to keep watch, and Isolda throws down the torch to the Death motive.  Tristan rushes in, and the most passionate love-duet ever written begins.

After the first ecstasies have subsided the lovers converse.  They must talk about something—­what should it be?  As Wagner’s thoughts were occupied with Schopenhauer at the time, he makes them talk a sort of pseudo-Schopenhauer.  Light is their enemy; only in night—­extinction—­can perfect joy be found.  It was the deceitful phantoms of daylight—­worldly ambitions—­that betrayed Tristan into acting so basely towards Isolda (before the drama opens); it was the light of the torch that kept him so long from her this night; and now in the darkness they find rapturous peace.  This is the substance of what is said.  Twice Brangaena warns them that the dawn is at hand, but they do not heed her.  Her songs are exquisite enough, surely, but the lovers, steeped in their bliss, have no ears for them.  Their own music is far more beautiful: 

[Illustration:  Some bars of music]

And again: 

[Illustration:  Some bars of music]

The lovers are presently awakened.  At the very climax of a mad, tumultuous passage Brangaena gives a scream; Kurvenal rushes in, and then—­enter Mark, Melot and the other hunters.  Melot’s trap has worked satisfactorily.

The cold red dawn slowly breaks.  The phantoms of the daylight have broken in upon the dream of night, which alone is true.  It is here that many would have the act terminate.  Such an ending would leave the idea of the act half expressed, and shatter the noble architectonical scheme of the whole drama.  The idea of the act—­that the light is the lovers’ enemy, the dark their friend and refuge—­has to be worked out to prepare for the last act; the