DUCASSE, PIERRE EMMANUEL ALBERT, BARON (1813-1893 ), French historian, was born at Bourges on Nov. 16, 1813. In 1849 he became aide-de-camp to Prince Jerome Bona parte, ex-king of Westphalia, then governor of the Invalides. He was attaché to Jerome's son, Prince Napoleon, during the Cri mean War. He was employed by Prince Napoleon on the Cor respondance of Napoleon I., and afterwards published certain letters, purposely omitted there, in the Revue liistorique. These documents, subsequently collected in Les Rois f reres de Napoleon (1883), as well as the Journal de la reine Catherine de W estphalie (1893), were edited with little care and are not entirely trust worthy, but their publication threw much light on Napoleon I. and his entourage. Ducasse was also employed by Jerome Bona parte and his son in the compilation of historical accounts of the affairs in which they were concerned.