Preliminary School Races.

The preliminary heats for the Interscholastic Rowing Association championship were rowed yesterday afternoon over the mile course beginning at Harvard bridge and ending at the Union Boat Club. Three heats with four crews in each heat were rowed with the following results:

First heat--Won by Noble and Greenough's; second, Waltham High; third, Mechanic Arts; fourth, De Merritte. Time 5m., 45 4-5s.

Second heat--Won by Stone's; second, Hopkinson; third, Volkmann; fourth, Roxbury Latin. Time 5m., 42s.

Third heat--Won by Brown and Nichols; second, Cambridge Latin; third, Boston Latin; fourth, English High. Time 5m., 53 2-5s.

The three crews winning second places yesterday will race today at 4 o'clock and the winning crew in this heat will race on Thursday, for the championship with the three winners of the preliminary heats.