Kirtley F. Mather, professor of geology, will speak informally tonight at 8 o'clock at the Boston Center for Adult Education, 79 Mount Vernon Street.

The subject will be: "Where Is the Stock Market Leading Us?" Other speakers will be Professor Brayton F. Wilson, of the Tufts College Economics Department and George R. Ericson, assistant financial editor of the Christian Science Monitor. The discussion will be open to the public.

Professor Mather is president of the Boston Center.