The old Italian school said that without portamento there was no singing, but only isolated notes void of all spiritual connection.

According to the Bernacchi school, one may illustrate the portamento by imagining two pearls strung on a fine thread. The pearls represent the two notes to be joined, and the thread the connection, the swift gliding of the voice from the one note to the other.

The most expressive and sympathetic portamento that I have ever heard is that of the darling of gods and men, Adelina Patti. I believe that scarcely any other songstress is equally rich in pearls. I mean those notes gliding like invisible pearls from her lips, and certainly more precious than all the pearls eye can behold. I never heard an artist equally capable of singing so much with so little expenditure of breath. A sparkling writer once called Italy “the Lord’s own conservatoire,” and in this conservatorio, said Hanslick, Adelina Patti has indisputably carried off the first prize.

According to the Bernacchi school, the portamento of the Italians consists in joining on two different syllables two notes which form a smaller or larger interval in such a way that by a gentle legato, commencing at the close of the first note, the voice glides rapidly over to the second note by means of anticipating it. Bernacchi adds: “It is the teacher's business to sing, and to continue singing, to the pupil the portamento, and to make him imitate it until it is entirely mastered." I think it is desirable, too, that the teacher should copy the pupil’s faults, in order to challenge his judgment, and to make his sense of tone more acute; for it is in human nature to judge our neighbours more accurately than ourselves. The fable has it: “Man carries his neighbour's faults at his breast before him; but his own faults he carries on his back, where he does not see them.”

It is the teacher's business to sing, and to continue singing, to the pupil the portamento, and to make him imitate it until it is entirely mastered.

Some Italians call the musical sign marking the portamento—the transition from one note to another—Il ponticello, the little bridge.” I should call it a magic bridge, the architect of which requires to be a noble artist, on whose skill both the safety and the beauty of the structure depend. The less material he employs in building it, the safer is the bridge, and therefore I may indeed call it a magic bridge, and warn pack-horses and heavy waggons not to tread it. Feelings only may traverse it and pass from soul to soul. To them alone it is open, and only at their command. Many nature-taught singers, indeed, think it melting melody and sympathetic expression when they very innocently mew their notes up and down with a rush of superfluous breath, often enough escorted by some nasal and palatal accessories. This is a style of execution which may meet with acceptance, but is by no means to be commended for imitation to the growing artist. Like religion, art ought to seek truth; and since all truth is harmonious, and all harmony beautiful, art must also seek beauty.

Portamento has its place chiefly in pieces in which tender sentiment is to be expressed; yet in the representation of violent passions, and in the delineation of gloom, not less than of the serene, and even in the recitativo, it may not always be dispensed with. The artist’s taste has in most cases to decide where portamento may be employed. Expressiveness is both the object and the effect of portamento, no matter whether love, grief, or joy be the emotions to be characterised. Still, as observed above, tender sentiment can least do without it.

—Albert B. Bach, On Musical Culture and Vocal Culture (1884), page 137-8.

Bach was a student of Francesco Lamperti. His works can be found on the download page.

Students of bel canto will be greatly aided by the Janet Spencer portamento recording (#5) which accompanies Hidden in Plain Sight: The Hermann Klein Phono-Vocal Method Based upon the Famous School of Manuel Garcia and can be accessed here.

A key device of the old Italian school of singing, portamento is a preparatory exercise for singing legato.