The Tribune’s Washington dispatch says a German printer boy who has been a year getting from New Orleans via Richmond, where he was imprisoned three months, has arrived here.

He estimates the number of fighting men at Richmond at 70,000, and confirms the report that four divisions under Longstreet, Ewell, Hill and Jackson are stationed along the railroad from Staunton to Gordonsville, and at Louisa Court House, under Stonewall Jackson, numbering in all. in his opinion, 50,000 men: but it is improbable that these divisions average more than 12,000 after the severe fighting on the Chickahominy. Thirty thousand is probably nearer the number. Their pickets extend to New Market, and their course appears to be up the Shenandoah Valley.

A letter from Norfolk states that there have been several cases of yellow fever there.