“ And be it further enacted, That the President of the United States be authorized to appoint, and by supplying vacancies happening from refusals to act, or other causes, to keep in appointment, as long as may be necessary, three commissioners, who, or any two of whom, shall under the direction of the President, survey, and by proper metes and bounds, define and limit a district of territory, under the limitations above-mentioned; and the district so defined, limited and located, shall be deemed the district accepted by this act, for the permanent seat of the government of the United States. ”