The dark night of superstition: two tales; Finding the Center: Two Narratives, by V.S. Naipaul. New York: Alfred A. Knopf. 176 pp. $13.95.

V.S. Naipaul's pair of narratives in ''Finding the Center'' seem unrelated at first. One is autobiographical; the other is a reflection on superstition in the Ivory Coast. As you read, though, they turn out to be circling the same themes in startlingly different ways.

Naipaul tells his ''Prologue to an Autobiography'' almost shyly. He starts with the moment he wrote the first sentence of the first book he got published, a book about a man who lived with Naipaul's family in Trinidad. He brings out one loop of revelation after another, but cautiously, never telling all at once. We see his impoverished life as a young colonial and Oxford graduate in London. He works through concentric rings of memory, historical fact, and disclosures by family members. The story takes us to Venezuela 27 years later to visit the subject of that first sentence, back to his childhood in Trinidad, and further back to his grandparents' emigration from India.

This is mainly a heartbreaking portrait of his father, a reporter who covered the Indian community for the Trinidad Guardian. It is also a portrait of himself as a son. He writes about his father's downfall with such tenderness that you can imagine him as a small boy.

During an outbreak of rabies on Trinidad, his father reported that Indians weren't innoculating their cattle. They didn't want to pay the high price of the medicine. And besides, they were sacrificing goats to the Hindu goddess Kali instead. After the story appeared, he got an anonymous note saying that he would die in a week if he didn't make the same sacrifice. This was a horrific insult to a man who was for religious reform and who, by his writing, was trying to escape the narrowness of Trinidad's Indian community. He found himself unable to stand up to the threat, however, and performed the sacrifice.

This is painful to read. Naipaul doesn't find out about it until after his father's death, when another journalist sends him a clipping about the event. It happened when he was a baby, and he had never heard about it. ''I was staggered, '' he writes. At first he thinks it must have been a joke. But he looks it up in the Trinidad Guardian and finds another reporter's account of the sacrifice his father performed. His father's article is there, too, but, Naipaul writes, ''he had no means of recording what he felt.'' That is the most tragic part of the story. It is as if superstition had won out over his father's feeling for the nobility of his craft.

After that, the senior Naipaul's career took a downturn. The Fleet Street editor who had taught him to write and had brought him along as a reporter until he was in conflict with his own community was dismissed. The elder Naipaul, too, was fired. He had a bout with madness and wandered the island doing odd jobs for a while. But he still loved his craft. He wrote stories while convalescing and found comfort in reading Marcus Aurelius and Epictetus. And he raised his son to be a writer.''What is astonishing to me is that, with the vocation, he so accurately transmitted to me - without saying anything about it - his hysteria from the time when I didn't know him: his fear of extinction,'' Naipaul writes.

So the image of the young Naipaul, writing that first published sentence in a state of desperate ambition, suddenly makes sense. You feel you have ''found the center'' with him.

Which makes ''The Crocodiles of Yamoussoukro,'' all the more chilling.

Here, Naipaul investigates the crocodiles that the President of the Ivory Coast keeps at his tribal village, Yamoussoukro, which has been made a monument of modernity as a testament to Ivory Coast's development. Daily, they are thrown a live chicken to eat in front of an audience. Naipaul talks to people about other strange happenings and then puts the events side by side to see if they shed light on one another.

But his questions keep leading to the ''world of night, the world of darkness ,'' as one African calls it, the world of animistic belief and supposed supernatural powers. Many of the people he talks to are foreigners who have chosen to live here and who love it, like the woman from Martinique who says that ''life is so big'' with the addition of this ''other world.''

Yet poking through the satisfaction and ''wholeness'' these people say they feel are the grisly little details he keeps wondering about. In the Ivory Coast, the servants of a chief are still buried with him, Naipaul is told. If they run away at his death, children are sacrificed instead. Someone tells him that, when the newspaper reports a child's disappearance, that child has been sacrificed. The newspaper describes a house that mysteriously keeps catching on fire, and attributes this phenomenon to evil spirits. He is told of the power of some Africans to turn themselves into ''pure energy,'' to travel instantaneously to Paris, say, and bring back news. In ''the world of night,'' with their supernatural powers, Africans have everything Europeans have brought about with technology, he is told.

Naipaul's shyness has become stealth. He tells you about human sacrifice calmly, in the middle of charming descriptions of the expatriates and Ivorian intellectuals and admiring comments on Ivorian development. It is as if you had found these things out by mistake. You don't even know whether to believe him, since he has said this is not a journalistic investigation. You feel alone in an alien world.

Naipaul has succeded in passing along his terror of superstitious thinking to the reader. At the end of the book, I yearned for the beginning with something like homesickness. The African life, with its integrated belief system in which ''the world of darkness'' is an accepted part of the terrain of thought, contrasts with Naipaul's edgy, alienated sense of the tight horizons of his childhhood. But I turned back and reread ''Prologue to an Autobiography'' because I couldn't leave the book that way. In this book, the search for the center is the center, and Naipaul makes the reader search, too.

In ''The Crocodiles of Yamoussoukro'' he pretends to withhold judgment, like a polite visitor, but in putting the two views of sacrifice together he really makes a severe judgment indeed. His aloof style in the second narrative is confusing. He seems to be writing about Westerners and Western-educated Ivorians' enchantment with ''the world of darkness.'' But ''Finding the Center'' could be read as a condemnation of Africans for being backward, written by someone who spoke more often with Westerners living in Africa than with natives. He reports that he looked away when the chicken was eaten by the crocodile - a perfectly sensible response. But why search for the meaning of something you aren't willing to look at?

What does come through clearly is that his search of newspapers, relatives' memories, and his own feelings in ''Prologue to an Autobiography'' is crucial. This is a chilling book that should be read 11/2 times.