of the thunder in the deep basses.  The curtain rises, disclosing the interior of a rude hut, its roof supported by the branches of an ash-tree whose trunk rises through the centre of the apartment.  As the tempest rages without, Siegmund rushes in and falls exhausted by the fire.  Attracted by the noise, Sieglinde appears, and observing the fallen stranger bends compassionately over him and offers him a horn of mead.  As their eyes meet they watch each other with strange interest and growing emotion.  While thus mutually fascinated, Hunding enters and turns an inquiring look upon Sieglinde.  She explains that he is a guest worn out with fatigue and seeking shelter.  Hunding orders a repast and Siegmund tells his story.  Vanquished in combat by a neighboring tribe, some of whose adherents he had slain, and stripped of his arms, he fled through the storm for refuge.  Hunding promises him hospitality, but challenges him to combat on the morrow, for the victims of Siegmund’s wrath were Hunding’s friends.  As Sieglinde retires at Hunding’s bidding, she casts a despairing, passionate look at Siegmund, and tries to direct his attention to a sword sticking in the ash-tree, but in vain.  Hunding warns her away with a significant look, and then taking his weapons from the tree leaves Siegmund alone.  The latter, sitting by the fire, falls into dejection, but is soon roused by the thought that his sire had promised he should find the sword Nothung in his time of direst need.  The dying fire shoots out a sudden flame, and his eye lights upon its handle, illuminated by the blaze.  The magnificent sword-melody is sounded, and in a scene of great power he hails it and sings his love for Sieglinde, whom now he can rescue.  As the fire and the song die away together, Sieglinde reappears.  She has drugged Hunding into a deep sleep, and in an exultant song tells Siegmund the story of the sword.  They can be saved if he is strong enough to wrench it from the trunk of the ash.  He recognizes his sister and folds her passionately in his arms.  The storm has passed, and as the moonlight floods the room he breaks out in one of the loveliest melodies Wagner has ever written, the spring song ("Winterstuerme wichen dem Wonnemond"), a song of love leading to the delights of spring; and Sieglinde in passionate response declares, “Thou art the spring for which I longed in winter’s frosty embrace.”  The recognition is mutual, not alone of brother and sister but of lover and mistress,—­the union which is destined to beget Siegfried, the hero.  Seizing her in his arms, Siegmund disappears with her into the depths of the forest, and the curtain falls.