DOROTHY WORDSWORTH. By Robert Gittings and Jo Manton. Oxford University Press. 318 pp. $17.95.

DOROTHY WORDSWORTH is a formidable subject -- formidable in her very elusiveness and modesty, her odd satellite fame encapsulated in obscurity. Before I opened this valuable new biography, I had never read a line of hers. This is the sum of what I knew: Wordsworth's sister, spinster, kept house for him, kept journals having to do with nature. Certainly I did not know she had written: "There was no one waterfall above another -- it was the sound of waters in the air -- the voice of the air." Or: "As I lay down on the grass, I observed the glittering silver line of the ridges of the Backs of the sheep . . . beautiful but with something of a strangeness, like animals of another kind -- as if belonging to a more splendid world." There is something translucent about lines like these, a voice we might almost call modern, yet we are over a hundred years away from Imagism and:

The apparition of these faces in the


Petals on a wet, black bough.

It is very possible that Virginia Woolf had Dorothy in mind when she wrote her famous passage in A Room of One's Own about Shakespeare's sister, that imaginary 17- year-old girl with a poetic gift equal to her brother's, who in 16th-century England, because of the condition of women, was bound to end up tragically -- dead at an early age or in the terrible isolation of madness. Things had improved -- but just barely -- by the end of the 18th century when a few women, mostly early popular novelists, were making their living by the pen; but for the most part, female writers did not aspire to poetry. Dorothy, with her genius for self-effacement, would never have called herself a poet; she was a diarist, a letterwriter, a keeper of quick jottings in journals to be shown only to those in her family circle and certain intimate literary friends, like Coleridge and DeQuincey.

THOMAS DeQUINCEY, write Gittings and Manton, "felt 'some subtle fire of impassioned intellect' burning within her. Moreover he understood how the sense of beauty, the sympathy swift as the pulses of light, and the innate charity of 'the lady who paced by his side continually through sylvan and mountain tracks' had humanized Wordsworth's austere genius, so that all 'worshippers through every age of this great poet are become equally her debtors.'"

Unquestionably Dorothy was her brother's muse. Still there was another role she might have played, a primary one. Perhaps, DeQuincey thought, she should have become "in good earnest, a writer," rather than drowning her imagination in the responsibilities of her brother's household. This was a possibility, however, that evidently never occurred to Dorothy. Courageous and hardy, yet emotionally fragile, she existed in the embattled state of what DeQuincey called the "self baffling of her feelings." By her fifties, the "subtle fire" had gone out. The brilliant, febrile girl with the unfashionably tanned face and the "wild and startling" eyes, who had tramped the mountains and woods of the Lake Country and walked through Germany and Scotland with William Wordsworth and Samuel Coleridge had given way to "poor Miss Wordsworth" who had quite lost her memory and her sense of things, and who lived confined in a quiet room, except for excursions in a bath chair around the garden.

It is in Dorothy Wordsworth's longing for a home that Gittings and Manton perceive the key to her character. This need, which would eventually overwhelm her creativity, sprang from the hunger of the orphan. From the age of 6, when her father sent her away after the death of her mother to live in the households of others as a poor relation, Dorothy Wordsworth had no home of her own. Curiously, the home she fantasized as a young girl was not one that she shared with a husband, but with William, the least promising of her four brothers -- an odd bird, unable to settle down to his studies for holy orders at Cambridge due to some misguided passion for poetry. "Love will never bind me closer to any human being than Friendship binds me to William, my earliest and my dearest Male friend," Dorothy wrote when she was 19. He in turn confessed to feeling for his sister, "a sort of violence of affection . . . a sort of restless watchfulness which I know not how to describe."

In 1794, the hopes of the two orphans were providentially realized when William received a small legacy from a wealthy young patron who had died of consumption, enabling him to devote himself entirely to poetry and to live with his sister, with extreme frugality, in Racedown Lodge in the West Country. Racedown, write Gittings and Manton, was "the scene of ents which were supremely important in the lives of Dorothy and her brother." It was there that ''she taught him to see life through her eyes, and specially to see Nature as it was and not through a curtain of literary allusion."

At Racedown, in the summer of 1797, an extraordinary person would enter their lives -- Samuel Taylor Coleridge, a young poet at the zenith of his brilliance (though secretly in thrall to opium), teeming, as Dorothy put it, ''with soul, mind and spirit." "It is surely impossible," write Gittings and Manton with characteristic excess of caution, "to use the words 'love' or 'in love' with any meaning about the three. They were all in a state of delighted wonder with each other, a type of joyful recognition and dazed bewilderment, for which there can be no rational account." Shortly after this meeting the Wordsworths would visit Coleridge in Somerset. Unable to forego his company and enraptured by the wild beauty of the counryside, they would move into an empty house, Alfoxton, to be near him. On the historic rambles in the Quantock countryside that fall, the magical rapport between the three of them burned higher and brighter and in this mutual conflagration Romantic poetry was born.

THIS WAS the period when Dorothy came into her own, when she first began to write her journals, and when she lived with a freedom unknown to most women of her station. Coleridge called her "exquisite . . . in her mind and heart." He found her taste to be "A perfect electrometer -- it bends, protrudes, and draws in at subtlest beauties and most recondite faults." One wonders, however -- and wishes her biographers had speculated much more upon this point -- about the extent of the intellectual inferiority complex Dorothy must have felt in the company of these two male geniuses. They, after all, had had classical university educations; she had read relatively few books and had mastered only the plain English of everyday communication, though she would later teach herself French and German. Would she have written differently -- less directly and eloquently -- if she had had the educational advantages of a young gentleman? Was she ever able to acknowledge to herself the crucial nature of her influence upon both Wordsworth and Coleridge? She had the fatal lack of ego, the extreme personal reticence of someone whose first concern was to tell the plain truth about what she saw around her. Or, as Virginia Woolf wrote of her in The Second Common Reader, she "never confused her soul with the sky. . . . For if she let 'I' and its rights and its wrongs and its passions get between her and object, she would be calling the moon 'the Queen of the Night,' she would be talking of the dawn's 'orient beam.'"

In a few lines, Woolf can somehow suggest to us the nature of the mysterious filial love of the Wordsworths, with its mysticism and muted eroticism: "It was a strange love, profound, almost dumb, as if brother and sister had grown together and shared not the speech but the mood, so that they hardly knew which felt, which spoke, which saw the daffodils or the sleeping city."

Gittings and Manton, however, show an amazing reluctance to delve too deeply into this remarkable relationship and credit Dorothy with no sexual feelings whatsoever: "Dorothy, it seems, knew her own nature. Family life was all in all to her; she loved children intensely and took pride in domestic duties well done. . . . Yet with all her lovable qualities, there is no sign that she ever aroused or experienced physical desire, nor that she felt this a loss," they write, and are content to leave it at that.

For Woolf, Dorothy is an ecstatic being, a pure poet to the bone -- a miracle. For Gittings and Manton, the miracle dwindles all too readily into poor Aunt Dorothy and her story, after William's marriage to Mary Hutchinson in 1802 and the advent of her many nieces and nephews, becomes a martyr's chronicle of linens washed, shirts sewn, infants cared for, gardens tended, invalids nursed -- the staggering, mind-crushing women's work of the 19th century. Biographers of the old school, they stick doggedly to what is palpably documented (their most important sources being Dorothy's letters and journals). Such scholarly responsibility is commendable, but in telling Dorothy's story more imaginative daring is called for, an x-ray vision that would penetrate the mass of mundane details that obscure the inner life.