The article -- apparently not included in their online edition except for subscribers -- is Richard Holmes's "The Fantoms of Theophile Gautier." Below are some of the parts that apply to Gautier's creation of the Giselle libretto. Most of us are at a little familiar with that story, but I -- at least -- knew less than I thought.
[H]is heart was ... utterly divided between two women.
They were the two famous Grisi sisters: Italians, artistically gifted, and astonishingly beautiful. One was an opera singer, the other a ballet dancer. Ernesta Grisi was stormy and passionate, and Carlotta Grisi was tranquil and utterly dedicated to her art. Ernesta lived under [Gautier's] roof at Neuilly and bore Gautier two daughters, while organizing his domestic life, singing under the trees in his garden, and cooking him risottos. Carlotta danced in all the capitals of Europe, exchanged love letters with Gautier for thirty years, and only once kissed him on the lips.
Back-tracking a bit:
Although the plot was based on an older German legend already developed by Heine, "[t]he whole trajectory of the story is pure Gautier, a story of agonizeed love from beyond the grave." Here is Holmes's translation of the beginning of Act II:
... Gautier was always haunted by material and earthbound lmitations: of his own heavy and demanding body, of his increasisngly domesticated career, and of his endless, treadmill newspaper-writing. ... On his return from Spain in the spring of 1841, where he had first observed fierce young Andalusian women dancing the flamenco ... he suddently saw the twenty-year-old Carlotta Grisi dancing on stage at the Opera. It was a coup de foudre, and he immediately decided to create a ballet for her.
For those who can get their hands on the August 14 issue, there's a charming colored lithograph of Grisi-as-Willi floating above her own grave. There's also a really stunning -- and to me totally unfamiliar -- oil portrait of "Two Sisters," by Theodore Chasseriau (1843). This painting, now in the Louvre, suggests, as Holmes sees it, "a profound truth about Gautier's schizophrenic desires, his mirror-image romances, and his looking-glass longings."
The theater reveals a forest on the edge of a lake ... The bluish light of an unnaturally bright mooon floods the scene with a chill, misty luminescence ... Someone in the distance midnight strikes. ... Hilarion and his friends listen to the clock with growing terror. Trembling they look about them, waiting for the apparitions of those lovely, light foot fantoms. "Quick, let's slip away," whispers Hilarion, "The beautiful Willis are pitiless, they seize hold of travelers and force them to dance, on and on and on, until they drop dead with exhaustion or are swallowed up in the icy waters of the lake." But already a strange and unearthly music is filling the theater."