GENERAL REPORT OF THE JUDGES OF GROUP XXI. International Exhibition. Philadelphia, 1876. Prof. F. A. Walker, Chief of Bureau of Awards : Sir,—In compliance with the instructions contained in your letter of June 22, with reference to a general report on the machine-tools of the Centennial Exhibition, we have the honor herewith to forward our reports on the several exhibits of Group XXI. with our recom mendations for award; and with that we also beg leave to submit our general report on the machinery of one of the most valuable and important sections in the Centennial Exhibition. We, the Judges, have the honor to be, sir, Your most obedient servants, JOHN ANDERSON, Chairman, GEO. H. BLELOCH, C. A. ANGSTROM W. F. DURFEE, F. REIFER, JNO. A. ANDERSON, F. PERRIER, AUG. GOBERT, Fils, Secretary.