Negro ghettos in large American cities will tend to be broken up during the next 20 years, Charles H. Tilly, lecturer on Sociology, predicted yesterday.

In response to a question from one of more than 200 alumni and friends in the Fogg Large Lecture Hall, Tilly said he expected "substantial dispersion of ghettos," although he warned they would not disappear completely. Tilly participated with Robert E. Lane '39, professor of Political Science at Yale, and William A. Doebele, Jr., associate professor of City and Regional Planning, in a symposium on "The Future of the City."

Tilly said three factors will tend to reverse the growth of Negro ghettos. First, he said, the rate of Negro immigration from the South to the urban northeast ("the most highly segregated part of the United States") can be expected to slow down.

Secondly, Tilly explained, wealthier Negroes will move to the suburbs, where experience indicates they will be able to find integrated housing.

"As Negroes prosper--and I expect they will prosper--dispersion will increase," he said.

And thirdly, public policy will make a conscious effort to break up ghettos. Tilly said that officials are realizing the potential of urban renewal to become more than just "Negro removal." But he also predicted that cities will employ more sophisticated tools to eliminate Negro ghettos.

One possibility suggested by both Tilly and Doebele is that local governments will begin to subsidize the rents of lower-income citizens in an effort to move families from public housing into the private market. They emphasized that private housing offers large opportunities for poorer families and that the freedom of the market will tend to aid integration.

In their opening speeches, both Doebele and Tilly tried to picture the city of the year 2000. Tilly said that population growth "suggests huge metropolises and densities that we haven't yet learned how to handle." The size of Greater New York, for example, will probably jump to at least 25 million from the present 10, and Calcutta, India, now smaller than New York, will rise to 36 million, he noted.

Lane attempted a shorter range political analysis of the city. "It is safe to predict--for how many years I don't know--that the Democrats will control the central city," he said.

The gradual disappearance of voting along ethnic or neighborhood lines except in the case of the Negro, has "tended to undercut the political machine" in urban areas, Lane observed.

As for the theory of an urban "power elite"--composed of the rich and well-born--that make most of the important urban political decisions, Lane said this model was a bit oversimplified and suggested that in many cities there appeared to be several "elites," each concerned with a different aspect of government.