A 'pccisl from Washington to the New York Trihune says: The largest pui tv e%'er . givon iij Washington carne i ff to-uiglit al the piva'e residencH of Charles Knapp, contractor for heavy cunuon. . Two Iioum'S bavo been conneeted into one by tearing down the wall. Culebrated caterers frora Now York have prepared the most oostly 8uppei' lor seve-n handred guest?; while green b. uses, far and noar havo been called upon for flowers to dec(irte parlors and tables. The nireet in front bas been floorcd and oarpeted; and it is estimated tbat the entertainment will cost $100,000- the frofit of abuul fij'ty gun.