The interest and curiosity of the public were, therefore, wrought up to an extraordinary pitch.  Her first appearance was on May 4, 1847, as Alice, in “Robert le Diable,” a part so signally identified with her great successes.  “The curtain went up, the opera began, the cheers resounded, deep silence followed,” wrote the critic of the “Musical World,” “and the cause of all the excitement was before us.  It opened its mouth and emitted sound.  The sounds it emitted were right pleasing, honey-sweet, and silver-toned.  With all this, there was, besides, a quietude that we had not marked before, and a something that hovered about the object, as an unseen grace that was attired in a robe of innocence, transparent as the thin surface of a bubble, disclosing all, and making itself rather felt than seen.”  Chorley tells us that Mendelssohn, who was sitting by him, and whose attachment to Jenny Lind’s genius was unbounded, turned round, watched the audience as the notes of the singer swelled and filled the house, and smiled with delight as he saw how completely every one in the audience was magnetized.  The delicious sustained notes which began the first cavatina died away into a faint whisper, and thunders of applause went up as with one breath, the stentorian voice of Lablache, who was sitting in his box, booming like a great bell amid the din.  The excitement of the audience at the close of the opera almost baffles description.  Lumley’s hopes were not in vain.  Jenny Lind was securely throned as the operatic goddess of the town, and no rivalry had power to shake her from her place.

The judgment of the musical critics, though not intemperate in praise, had something more than a touch of the public enthusiasm.  “It is wanting in that roundness and mellowness which belongs to organs of the South,” observed a very able musical connoisseur.  “When forced, it has by no means an agreeable sound, and falls hard and grating on the ears.  It is evident that, in the greater part of its range, acquired by much perseverance and study, nature has not been bountiful to the Swedish Nightingale in an extraordinary degree.  But art and energy have supplied the defects of nature.  Perhaps no artist, if we except Pasta, ever deserved more praise than Jenny Lind for what she has worked out of bad materials.  From an organ neither naturally sweet nor powerful, she has elaborated a voice capable of producing the most vivid sensations.  In her mezzo-voce singing, scarcely any vocalist we ever heard can be compared to her.  The most delicate notes, given with the most perfect intonation, captivate the hearers, and throw them into ecstasies of delight.  This is undoubtedly the great charm of Jenny Lind’s singing, and in this respect we subscribe ourselves among her most enthusiastic admirers....  She sustains a C or D in alt with unerring intonation and surprising power.  These are attained without an effort, and constitute another charm of the Nightingale’s singing.