In front of the Canadian Parliment, a great torch blazes in dedication to "National unity."

But Canadian unity is being eroded today by divisions that are adding power to the 10 provinces, already strong, and weakening the federal government.

"We're in the flow of power now toward the provinces," says a former federal official, "part of which is caused by the over-reach of government - the same forces that brought about Proposition 13 (in California). So the correct political and economic posture is to accomodate that end. It'll flow back - it won't destroy the country."

The decentralization trend is clear, even though the once-feared clout of the separatist movement in French-speaking Quebec Province has faded. A recent poll by the Canadian Broadcasting Corp. indicated that Rene Levesque's Parti Quebecois probably would lose power in the next election - 1980 or 1981 - to the Liberal Party, whose provincial leader is a popular French Canadian, former journalist Claude Ryan.

To be sure, Ryan insists on a special French identity for Quebec but he appears willing to let French nationalist and cultural objectives evolve within the federation - rather than outside, which has been Levesque's objective.

Friday, Quebec's provincial assembly passed, 59-17, a law laying the groundwork for a referendum on the independence issue. Levesque has promised such a vote in the next two years. Liberal Party efforts to make the referendum a confidence issue were defeated.

Quebec's fervent French nationalism has roots not only in 300 years of settlement in the St. Lawrence Valley, but also in economics. Although 80 percent of Quebec's citizens speak French, the provincial economy is dominated by English speakers.

According to a recent survey, 85 percent of the top 110 corporations in Quebec are owned by English-Canadians. Almost 9 out of 10 of those has not a single-French speaker in the top management.

Guy J. Desmarais, president of a Montreal investment firm, points out that the Anglos' exclusion of the French from private economic affairs drove them into government service, where they gradually used political power to put the squeeze on the English - culminating in the Levesque victory at the polls in 1976.

But whether Levesque's or Ryan's party eventually holds power in Quebec, most observers had agree that neither Canada nor Quebec is ever going to be the same. Prime Minister Pierre Elliott Trudeau proposed constitutional reforms last week that not only guarantee equality of language rights for all French Canadians but call for a greater role in Ottawa for all of the provinces.

The principal mechanisms he proposed are an altered upper house in Parliament, with more equalized representation, and a revised Supreme Court giving the provinces more representation.

Thus western British Columbia would get a permanent seat on the Supreme Court, where the booming province has not had Supreme Court justice since 1962. Quebec would have four instead of three.

Trudeau's effort to give the provinces more say, and thus defuse the separatist movement, goes too far for some and not far enough for others. For the great bulk of English Canada - which outside of Quebec tends to be bored with the separatist issue - Trudeau has already made too many concessions to French nationalism.

Recently the wealthy province of Ontario, dominated by English-speaking Protestant - but with the largest French-speaking population outside of Quebec - refused to back legislation guaranteeing that federal publications would be provided in French as well as English.

Gov. William G. Davis' provincial government in Ontario has voluntarily added more French-language services than used to be the case. But in fact, there is little sympathy in much of Ontario for bilingualism, an attitude that has earned the province, and its capital, Toronto, a "redneck" reputation.

"The degree of prejudice against the French here is enormous," says Prof. Douglas Hartle of Toronto. "Language has replaced religion as a source fo antagonism.

"Ontario has a long, long tradition of Protestant-Catholic antagonism, the sort of situation that may have existed in Boston some years back." In small towns of Ontario years ago, Hartle says, "the Irish Protestants met and yelled against the pope, very much like in Northern Ireland."

The current more civilized but still snappish mood among the provinces is illustrated by Quebec's insistence on giving priority to that province's construction workers in Hull, Quebec, just across the river from Ottawa, which is in Ontario.

Ontario Gov. Davis has retorted with a demand that the Supreme Court rule Quebec's step unconstitutional. Failing that, Davis, said in an interview, he'll try to block Quebecers from construction jobs in Ontario. "I suppose we'll hear the 'redneck' charge again," said an Ontario government staffer, "but what else can we do?"

Hartle, an unofficial adviser to many Canadian governments, says that "this mood toward increasing provincial autonomy isn't going to be reversed."

The Canadian provinces already have much more power vis-a-vis the central government than to the separate states in the United States. Now, the provinces want the Ottawa government to lower federal taxes so that the provinces can raise their own rates without annoying the taxpayers.

The are also seeking a curb on the power of the federal government to spend money, which the provinces argue allows Ottawa, rather than the several jurisdictions, to set priorities.

Another concern is that the federal government has become increasingly involved in polices on natural resources, which nominally are in provincial jurisdiction. For example, oil-rich Alberta wants to control its own supplies, and would like Ottawa to keep its hand off.

At a minimum, analysts here think that even if the provinces cannot keep control in the face of what amounts to a national issue, as in the case of energy, they will force Ottawa seek concurrence through consultation.

These analysts expect a continued movement of financial power from Montreal to Toronto, which is already the real center of banking and insurance. But there is a further shift ahead to the west. Already, more of Canada's gross national product comes from west of Ontario than east, reversing the situation of two years ago.

An important question to which there is no ready answer is how a trend toward a weaker central government would affect Canada's ability to deal effectively with other large industrial nations on key international questions.

Meanwhile, Trudeau and the federal bureaucracy here keep trying to promote "a Canadian identity" based on the diverse nature and twin cultural origins of Canadian society. They try to persuade the Quebecers that French culture will have a better chance to survive within a Canadian nation, where the French are 25 percent of a total 24 million population, than as a tiny ghetto on its own among several hundred million North Americans.

But just as Trudeau also struggles to prevent the whole of Canada from being assimulated by the colossal impact of American culture, the Quebecers fight against being assimilated into what Camille Laurin, Quebec's minister of cultural development calls "the North American melting pot."

"Except for the war years," says a thoughtful Canadian, "and perhaps a burst of feeling around the centennial" in 1967, "we've never come together as a nation. For the rest, Canada has simply been a commercial operation.