Despatches have been received here from our brave Army of the Potomac up to last night. It is announced that Gens. Barlow and Schimmelpfenning were both wounded and fell into the enemy’s hands in the engagement of the day before yesterday. They, with Generals Reynolds and Paul killed, were the only Union general officers who met with casualties. It is definitely stated, we hear, in the despatches referred to above, that the battle was fought on our part only by the First and Eleventh army corps; while the rebel force engaged against them were believed to embrace two-thirds of Lee’s entire army.