Tho House Committeo on District of Colurabia have called upon the District Commissioners to answor in writing numerous inquiries concerning their ofn: cial acts, affecting salaries, payments of all kinds, work given out in the absence of advertisement, and asking wheiher the improvements of streets or sewers have beon made, or any money expendod in or about roads, streets, avenues, parka, canals, or sidewalks, or certificates or bonds issued therefor, since June 30th, 1874, that either were not necessary to the Pxeuution of legal obligations or contracta existing at that date, or to the protection or preservation of iinprovenientg then existing or coramencod and not eotnpleted at that dato. If so, stato and speeify what improvements havo been so made, in what parts of the city, who were the contractors on said work, how they were paid, in 3.65 bonda, or otherwise, and the arnouut so paid, now due, or to become due to such contractor. Further, stato whether there was any open competition for such work undor advertisements, and if so, in what cases, and whether the lowest responsible biddor obtained tlio contract. The commissiuncrs are also asked, among othor things, to stato whether thev have made any estimate of the personal property in the Distsict that can bo reached by taxation, if so, state that nstimato and the uuiount of tax that in their opinión can bo realizcd therei'rom, at the present ratea, and at 2 per oont. on said valuation. The committee will thoroughly investígate all the official accounts of tho commissioners from tho District.