SEPTEMBER 7TH.—We see by the Northern papers that Pope claimed a great victory over Lee and Jackson! It was too much even for the lying editors themselves! The Federal army being hurled back on the Potomac, and then compelled to cross it, it was too transparently ridiculous for the press to contend for the victory. And now they confess to a series of defeats from the 26th June to the culminating calamity of the 30th August. They acknowledge they have been beaten—badly beaten—but they will not admit that our army has crossed into Maryland. Well, Lee’s dispatch to the President is dated “Headquarters, Frederick City.” We believe him.