An Asterisk From Yourcenar : THAT MIGHTY SCULPTOR, TIME, <i> By Marguerite Yourcenar Translated by Walter Kaiser (Farrar, Straus and Giroux: $22; 211 pp.)</i>

There is a moment in Marguerite Yourcenar’s new book of essays, “That Mighty Sculptor, Time,� when the writing springs shockingly, almost violently to life. Unfortunately, the writing isn’t hers. It comes when Yourcenar quotes from the minutes of a torture session undergone in the year 1600 by Fra Tommaso Campanella at the hands of the Inquisition.

Told he will be tortured, Fra Tommaso cries: “Please, no! What do you want of me? I’m dead.� He is asked why he will not answer his torturers’ questions. “I can’t,� he says. “Aaaah, aaaah, aaaah! Assholes! My whole body hurts, brother . . . Let me down . . . Have you no pity?� Why does he not tell the truth, his torturers demand? “I can’t stand it anymore. Brother, I’m pissing . . . My God, I’m dying!�

It is an extraordinary, terrifying scene, one made all the more chilling by its contrast to the crystalline prose Yourcenar uses to describe it. To be plunged back into the 17th Century, to have that brutal moment leap up and grab us by our throats 400 years later, makes us fall back in horror.

And yet Yourcenar’s perspective on the piece is curious. Another writer might have focused on the torturers’ barbarism, on the staggering viscerality of the event, even on its relationship to the human-rights abuses of our own times. Instead, Yourcenar uses it as the centerpiece for, of all things, a discussion of linguistics. And there, in one instance, is everything that is both so original and so maddening about this work, a posthumous translation of an essay collection first published in France in 1983.

Quoting Fra Tommaso’s passage at length, she tells us: “It has not been sufficiently emphasized that although we possess an enormous mass of written documents, and also visual documents, from the past, nothing is left to us of voices before the first nasal-sounding phonograph records of the 19th Century. . . . Nothing, or virtually nothing, is left us of those inflections, those quarter tones, those articulated half smiles which yet can change everything.�

Inflections, quarter-tones, articulated half-smiles--these are the things of Yourcenar’s world, the intriguing byways through which she attempts to elucidate our universe, and above all the past. It is her exceptional ability to command these that made her 1951 novel “The Memoirs of Hadrian�--the book that established her reputation outside France, in which she brilliantly distilled the limpid tones of the Roman Emperor--so effective. It was that same ability that made her first novel, “Alexis� (a first-person confession in which a man tells his wife of his homosexuality--perhaps also a veiled admission of Yourcenar’s own homosexuality), so profoundly moving. But where, oh where, in this new book is the depth of psychological insight, the concealed passion, the humanity that made those novels so compelling?

In essays whose subjects range from a few lines of the Anglo-Saxon church historian, the Venerable Bede, to a dream of the great Northern Renaissance artist Albrecht Durer, to the erotic themes of the Indian “Gita-Govinda,� Yourcenar displays all the breadth of understanding and range of knowledge one would expect from this most intellectual of writers, the first woman elected to membership in France’s prestigious scholarly body, the Academie Francaise. And it must be said that there’s something remarkably invigorating about her intellectualism. In an age dominated by the quick fix of television, by a rejection of the full weight and scope of ideas, it can be a pleasure to escape into Yourcenar’s studied cerebralism.

But cerebralism never rises above petty scholarship here, precision never above mere pedantry, as if Yourcenar were giving us simply the footnotes to the deeper preoccupations that have haunted her works.

There’s no doubt Yourcenar is one of the most original and rigorous writers of our century. A woman of vast intellect, of monumental classical knowledge, she managed at her best to make the voices of the past speak out to us, capturing all the fine shadings, the subtle nuances of power and personality, that most intrigue us. When she died in 1987 at the age of 84, Jacques Chirac, the French premier, justifiably compared her in importance to Jean-Paul Sartre.

But one would never guess that from this slim volume. Indeed, when one has finished, one can’t help but compare it with the Victor Hugo poem from which it derives its title. There, in one simple line where Hugo speaks of “the muted whisper of blurred memories,� it seems to be he manages to capture our imaginations more than Yourcenar does in a whole book.