There is a magic stillness in this Sleepy Hollow of a university town, where time seems to flow slowly around the brightest and best of young white Afrikaners as they stroll back and forth to classes on their leafy, quiet campus.

Fitted gracefully into rolling vineyards at the soot of regally proportioned sandstone mountains. Stellenbosch University has produced six of South Africa's seven prime ministers. Now, for the first time, it is producing uncertain Afrikaners.

"We were getting stronger and stronger," an Afrikaner woman student said after a class recently. "We knew we are born into a paradise. Then we failed in Angola, the government didn't explain it to us, and now things seem to be moving too fast for us to control them."

Her unfocused anxiety may turn out to be as exaggerated as was the complacency and overconfidence of Afrikaners students interviewed here in 1970 about the future of southern Africa. Then none of them evaluated the forces that brought the collapse of the Portuguese colonial empire and last year's bloody rioting, which struck even this bucolic setting.

As long ago as 1900, W.E.B. Du Bois, the leading black American intellectual of the first half of this century said, "The problem of the 20th century is the problem of the color line."

The black uprisings and spread of "Black Consciousness here have given the African majority only the most tenuous kind of power when balanced against the still-leashed military power the white government possess.

It is the kind of power a pedestrian has when trying to get to the other side of a street along which a fast-moving car is hurtling. It is the power to step forward and try to force the driver to stop.

What has shaken white South Africa is that young black Africans have taken that step over the past year. They have forced the whites to consider how many blacks and persons of mixed race they are prepared to kill to project the reigning social order of prejudice and privilege.

African political leaders think, perhaps optimistically, that such challenges will continue and that the whites will at some point stop the "one-way bloodshed," as one black called last year's disturbances.

"The military, economic and political power is all in white hands," a black leader said. "It fills you with despair until you realize that it all rests on the black labor force. Will they shoot the labor force that makes this country work."

A politican speaks of radicalization and a polarizing of attitudes here. In the business world, South Africa is said to have moved into the risk category.

In a literary sense, what has happene is this: The flawed success story that South Africa was at the turn of the decade is rapidly turning into a long-run tragedy, whose denouement will enflame racial and social conflicts across the globe.

South Africa is not a final act, however. The Afrikaners who have made themselves into the only white community ever to know Sub-Saharan Africa both intimately and, through their origins, in a non-colonial manner, will not retire from the stage simply because the rest of the world is calling for the curtain.

The world confronts in the Afrikaner power structure a dynamic, radical and counter-revolutionary force, not the conservative status quo-seeking settlers of Rhodesia and other former colonies.

How the Afrikaners succeed, or fail, in living with themselves and their countrymen of another color will affect relations all along Du Bois' correctly phophesized crucial global color line. South Africa is an important opening act in the drama of whether the white-dominated technological world will come to terms with decolonized regions known as the "Third World."

To defend the shortcomings of their own system, the Afrikaners reasonably point to the upset and chaos of much of Black Africa for the past two decades. They dwell on the moral cowardice of most of the continent's other leaders in nod denouncing atrocities like those of Uganda's Idi Amin - whose 1971 coup against Milton Obote was initially wecomed, in informal ways, by the South African government as well as by Israeli and American diplomats in Kampala, who were also later to change their minds.

The Africaners rail against the "double standard" of the "Afro-Asian bloc" at the United Nations for ceaselessly censuring South Africa while ignoring more systematic and brutal repression by blacks against blacks in Uganda and elsewhere.

In truth, the "bloc" is applying a single standard for its criticism - color, the exact same standard South Africa applies in preserving its "traditional way of life." They are helping make another prophecy, this one of former British Foreign Secretary Michael Stewart, increasingly true. Tyrannies based on race may or may not be more evil than other tyrannies, Stewart has said, but "at the present time in the history of the world, they are infinitely more dangerous."

There are more than 2,000 black college graduates in South Africa today. They have the same political rights and control over their lives as the most backward tribal farmer - essentially, none.

Rightly or wrongly, this affronts the newly developed Western sense of racial decenery, and opens South Africa to criticism. But something far more dangerous for the ruling white elite is beginning to happen in the beloved country.

Politically powerless Davids against the Afrikaners' Goliath, black students head their list of grievances with demands for equality - in education, pay, property ownership and before the law. Asked why they were not taking their school examinations, students gave this list of their political movement's goals. No. 8 refers to Bantu Administration Board, white government's apparatus for control over blacks. "Bottle stores" in No. 10 refers to white government-owned liquor stores in black townships. Prisoners held on Robben Island, No. 11, are policital detainees.

Twenty years ago, one of South Africa's shrewdest liberal educators, Julius Lewin, wrote an essay entitled "No Revolution Around the Corner." He still feels that the title applies.

Seven years ago, at the beginning of self-imposed exile in London, Lewin could confidently, if unhappily, repeat: "In South Africa today, most people do still behave as if they felt that, with all its weaknesses, the country were a going concern. Only a small minority thinks otherwise, and even their actions commonly belie their fears."

Today Lewin has changed his view. "The ruling white people are beginning to lose faith in the permanence of the whole system of government, including racial subjugation. Loss of faith by itself does not produce deep economic or social change. This first serious loss of faith is not the end, but the beginning of a long, long process that will bring the change men have sought for so long," he now says.

The rest of the world is deeply involved in South Africa. In some important ways, this country has been maintained as a large mining camp, with the English-speaking whites and the Afrikaners alternating as overseers. International financial, technological and more recently military links have all helped to keep an unjust society a workable one.

Last year's riots, the coming of age of an African generation demonstration that Africans themselves can master technology and business arrangements or make mutually profitable deals with outsiders to manage complex undertakings, and the growing failures of white management here have all raised a new and important question: Has the kind of white racism that continues to be practiced here become a prohibitively expensive luxury for everyone except the whites who defend it?

If the international financial community and Western governments should answer that affirmatively, white rule is finished here in South Africa.

A key lesson of the Middle East for 28 years, of Angola last year end of Rhodesia right now is that if one superpower is committed to violent change (and the Soviet Union is committed on the black side in southern Africa) and the other superpower is not committed to halting it, the change will occur.

That combination of forces, not historical justice, would end a society that would have become both unjust and unworkable.

South Africa is more like the United States than any other country I know. They are historic siblings. Lacking the population and adventurous spirit of frontier Americans, however, the Dutch settler community at the tip of Africa did not kill off the indigenous tribes it found there. By the time gold and diamonds were found, and cheap labor was needed, the settler lacked an incentive to kill off the blacks.

In his splendid book, "America," Alistair Cooke quotes "A wise Frenchman" as saying, "Liberty is the luxury of self-discipline." Cooke adds as a caution against trends in modern America that disturb him: "Historically those people that did not discipline themselves had discipline thrust on them from the outside."

Africaners, who see permissiveness in other "white" societies as the world's gravest danger, have by tie-fault become the world's most permissive society when it comes to white racism. The government of Prime Minister John Vorster lays few bars to the exercise of racism by its white electorate, and lacks either the courage or perhaps the sincerity to tackle this directly.

Rhodesia's Ian Smith and Henry A. Kissinger, among others, suddenly began laying stress on the absolute need to protect "minority rights" as part of any settlement in southern Africa when Rhodesian guerrillas began serious warfare there.

"Shouldn't somebody be asking these whites, "Did you protect the majority when you had the chance?" asked black writer Nimrod Mkele. "Protection of majority rights in the present would be the best way of insuring protection of minority rights in the future."

Like most of the scores of blacks I interviewed in a six-week tour of South Africa. Mkele has grown progressively more bitter tone and more definitely outspoken in the six years since my last previous visit. His typewriter, files and even his secretary were impounded by security police shortly before my visit and the secretary remains under arrest without charge.

But, astonishingly, there is still a reservoir of good will and faith toward whites among adult, educated Africans. There is still a good chance of reaching multiracial compromise and sharing, if the white leadership will seek it.

There are few signs of that good will among the young adults and teenagers of the next generation, however, and each arrest and killing of blacks for essentially political reasons reduces it geometrically.

Prime Minister Vorster came to office in 1966 suddenly, and with promise. He initiated an "outward" policy toward the rest of Africa to reduce tensions. It was that policy, and not Kissinger's promises as Vorster hints to interviewers that dragged him into Angola, left in ruins his efforts to come to terms with the rest of Africa and, probably, immobilized his government from being able to make the sweeping changes needed now in South Africa's racial quagmire.

His successor may still have time to do so. The most likely candidate ta the moment, Interior and Information Minister Connie Mulder, shows signs of understanding the Western world and the current requirements for standing in its good graces better than most of his elders in the Cabinet do.

Otherwise, South Africa is likely to be dragged by the forces gathering around it at the moment to confront at least two sobering questions.

One simply is based on the double failures of, first, the old liberal multiracial ideal of a common society, and now of the original aparthied notion of expelling blacks physically or politically out of the 87 per cent share of the country the whites claim for themselves, giving them a monopoly on 90 per cent of the country's economic means of production.

Greater bloodshed and the beginning of serious urban terrorism, for the fist time in Sub-Saharan Africa, are likely if radical changes are not made by the government. This will bring closer the possibility of a negotiated partition between blacks and whites in this country.

Zulu Chief Gatsha Buthelezi is already thinking about such prospects, telling friends that a viable deal means all of Natal Province, including Durban's giant harbor, for the Zulus as a starter. While not having anything nearly so grandiose in mind, a few of the likely post-Vorster Afrikaner political leaders have begun to discuss a new and more generous, splitting up of the land if it will protect white privilege, which goes under the rubric of "cultural identity" here.

The other question for the future comes from Alan Paton, South Africa's greatest writer. Six years ago, I could end a series of articles on South Africa with a not-pessimistic quotation from his play, "Sponono," where a black character says to a white: "You are, whether you like it or not, your brother's keeper . . . We are bound together, for better or for worse."

Time has moved, more rapidly than many of us expected and the clock is still running. Today, it is a quote from "Cry the Beloved Country." Paton-prophetically put it in the mouth of the figure that is emerging as the rallying point for Black Consciousness here, the black priest, who says of the whites.

"I have one great fear in my heart, that one day when they turn to loving, they will find we are turned to hating."