The Salem ydiurdcr.-I'here has per haps never been criminal case in this country which has more widely excited interest, than the murder of AIr. White of Salem. The circumstances of the murder we published at the time of it's occurrence. The train of deyelope- ment by which it's perpetrators have been detected, owing to it's prolixity, and the distance at which fl tfanspircd, we have omitted to detail. One of the muraerers J. r. Knapp, after a trial before two j;irics has finally been een- vieted, and will, undoubtedly suffer the penalty of death. The first jury was unable 10 agree, and was kept together ten days. Mr. Webster was employed as assistant 10 the prosecuting attorney, and is said to have fully excrtedhis great abilities.