Arlington Cemetery.The lofty plateau ol Arlington has been converted into a national cemetery for our brave .soldiers and Bailor who die in or near Wshiupton. It wa.' opened tor interment Mi y 1, 1*64, and within the year five thousand have been buried there. In a year or two more it w'Ubethe most populace city of the dead on this «ide of the Atlantic. It* conversion into a cemetery renders it impossible that it can ever be um*J as a residence again, General De Rustev has already removed his headquarters from there to the house of Gen. Lee's sou. immediately north. Many ol the graves contain the bodies of southern isoldiers who died in our hopita-. but then in every case the hcadl^oard of the . grave bears the word ‘‘Rebel, in large letters, on it.