We have theiollowing iDterest-ifig letter from a gentleman whohas been travelling:As Washington territory no-rices with marked appreciation, her Oregonian acquisitions, a* wiuness—Jacobs, the Dresentaiive to9 *Congress, another, his successor elect, Drents, another Oregonian,s tColambii couutv, and Dayton* 1 *in particular, boasts of Douglas county material among her many inhabitants. Much, hei very best as among the old Umpquaites, Icout he t eastcouitow htil oitionTheinfiitoras e littlrtfi