Death of Col. Sackett. From the Albany Evening Journal, July 20. Another name is added to the list of hero mar- tyrs who have fallen in the service of their country. Col. WILLIAM SACKETT, of the Nonth New-York Cav- alry, (son of Hon. W. A. SACKETT,) was mortally wounded in the engagement, under Gen. SHERIDAN, at Pavillion Station, Va., and died on the 14th ult. As he was left behind, the sad intelligence of his de- cease has but just been received. Col. SACKETT had seen much service. He entered the army on the 22d of April, 1861, was appointed Major of the Ninth New-York Cavalry in October of the same year, was promoted to Lieutenant-Colonel- cy in August, 1862, and in March, 1863, became com- mander of the regiment. He was with Gen. McCLEL- LAN in the Peninsula campaign, was in all the cavalry actions of the campaign which followed, was with the army in its advance after the battle of Antietam, and in almost constant conflict with the enemy until after the battle of Fredericksburgh. He par- ticipated in most of the cavalry engagements under Gen. HOOKER'S command, was in all of the principal cavalry actions during LEE'S invasion of Maryland and Pennsylvania in 1863, and was among the first engaged in the terrible conflict at Gettysburgh, where he performed distinguished service in holding a rebel brigade in check a long time while our forces were getting into position on the crest of the hill. He was active in the cavalry skirmishes which en- sued in the latter part of the Summer. During the present campaign he was with Gen. SHERIDAN in all his brilliant expeditions up to the time when he fell. He died while leading a charge against the enemies of his country--died, as he wished to die, doing his whole duty. He was brave, he was generous, he was unflinchingly faithful to the cause of the Union. He loved the old flag with a love that was stronger than life, and esteemed it glorious to fall in its defence. He was born in Seneca Falls, and was 25 years of age.