Mayor's Conference on Teachers' Pay Raises - Salary increases for Boston teachers which would cost $400,000 this year were discussed at City Hall today. Conferees, front row (left to right) were Michael J. Downey, assistant superintendent of schools; Mayor Kerrigan, and Budget Commissioner Herman L. Bush. Back row (left to right) Charles E. Lee, Boston Chamber of Commerce; John A. Sullivan, budget technician; City Auditor Charles J. Fox, Robert E. Cunniff, secretary of Boston Finance Commission, and John J. Costello, acting secretary of the Municipal Research Bureau.