BOOK REVIEW : Illusory Love for Africa Dies in Ethiopia : AFRICAN VISAS <i> by Maria Thomas</i> ; Soho $19.95, 242 pages

There are stories of such barnyard mismatches as the horse who fell in love with a hen. It was blind love; yet it was a blindness that puts a hen in a new light, even if it doesn’t tell us much about a horse.

Maria Thomas fell in love with Africa and wrote of other Americans who did. The loves were quixotic, narcissistic, escapist or idealistic, and none of them could really take.

Westerners--whether missionaries, technical advisers, Peace Corps volunteers or wanderers thinking to find themselves--never really were there, even if they thought they were. It was an illusion.

It is the illusion she wrote about, and she did it so remarkably, with such trenchant perception and lightness of spirit that it was an act of expansive discovery. How much humankind learned about the universe, along around the end of the Middle Ages, when it learned how little it knew.

Thomas’ illuminated illusions were tragically brief. She wrote a splendid novel, “Antonia Saw the Oryx First,” and a scintillating set of short stories, “Come to Africa and Save Your Marriage.”

In 1989, this former Peace Corps worker was killed, along with her husband, in a plane crash in Ethiopia. They were part of a mission headed by Rep. Mickey Leland of Texas--who also died--to visit refugee camps on the border.

“African Visas” is a posthumous collection, including a novella and six short stories. The stories offer glimpses of Thomas’ power to evoke moments of unexpected vision from her collection of foreign adventurers as they stumble among Africa’s signs and mysteries.

In “Ethiopia,” a striking phrase suggests the unreachable and unforgetable allure that flickers through a land so particularly trampled and tormented. Noting that the Peace Corps had its highest rate of dropouts there--and its highest rate of re-enrollments--Thomas writes: “Ethiopia kept the sacred image of itself, its own icon.”

Most of the short stories, though, seem unachieved to varying degrees. They move to suggest a transforming insight without elaborating sufficient clarity or sufficient suggestiveness to satisfy us as to its nature. The novella, on the other hand, is Thomas at her very best and--the two go together--most sneakily original.

“The Jiru Road” is a lovely kaleidoscope, ironic and rapt by half-turns. A story about a group of Peace Corps volunteers attempting rural development in the Ethiopian hinterland, it ends with a perfect image of futility. A helicopter carries one of the volunteers back to the capital after a torrential rainstorm and the anti-Western military revolt that deposed the emperor, Haile Selassie. She spots the road she has built and a bridge that another volunteer has built. The road is washed out; the bridge stands on dry land, its river having moved its bed.

And yet, as told by Sarah Easterday, the volunteer, it is far more than this. Rangy, flat-chested, thick-spectacled, awkward, she freely portrays herself as a latter-day Olive Oyl.

She chose the Peace Corps to avoid “conscription into America,” she continues grandly. She is grand, but she is not pretentious. She trips up continually, but she is no klutz. She is utterly and winningly open. And she tells us--wryly, fiercely, meditatively--what has filtered or crashed through that openness.

There is the lassitude she feels, day by day, in the remote village where she teaches English to starving children.

There is the ingenious idea--abetted by Wally, the volunteer in the next village, and by Jack, a hard-drinking construction engineer with a helicopter and influence--to build a road. As a road, it is useless. On the other hand, it qualifies the villagers for food deliveries.

There is the awful death of Wally, who has brought along his collection of 22 telescopes, from rabies. There is Sarah’s timid, distant friendship with the villagers, and the beating she receives after taking part too vigorously in a drunken village dance.

There is, above all, her voice, schoolgirl-corny at times (“Yes, Easterday, my girl, back to Jiru. . . . Ho! Ho! Tum de dum!”) and searching at others. Of her Ethiopian she says: “His beauty was astonishing but it looks sinful, somehow like a price not a gift, and for a split second I was glad of my awkward shape and homely features.”

At the end, mauled and frustrated, there is only one failure. She and the other volunteers are expelled and must leave.

There has been hardly a word of love in her whole story, but it is a love story nonetheless. Not for her beautiful Ethiopian aristocrat, but for Ethiopia.

It is the mystery of Thomas’ eldritch gift--she looks distantly at Africa as the fairies once looked at us--that without quite understanding this possession, we are in no doubt about it.

Next: Judith Freeman reviews “Heat and Other Stories” by Joyce Carol Oates (A William Abraham book/Dutton).