Nicholas Rossolimo, the international master who nipped Reshevsky at Long Beach, Calif. Some two years ago will be at Mechanics' Institute for an exhibition on Saturday, April 27th. It will be $2.50 a board. Interested parties see Mr. Stewart Samuels or Mr. A.B. Stamer at M.I., 57 Post St., chess room on 4th floor, or phone EX 2-9515. Get your reservation early as they're selling fast.