Washington City, March 31, 1840
The President of the United States, finding that different rules prevail at different places, as well in respect to the hours of labor by persons employed on the public works under the immediate authority of himself and the departments as also in relation to the different classes of workmen; and believing that much inconvenience and dissatisfaction would be removed by adopting a uniform course; hereby directs that all such persons, whether laborers or mechanics, be required to work only the number of hours prescribed by the ten-hour system.
M. Van Buren
A Compilation of the Messages and Papers of the Presidents 1789-1897, James D. Richardson, ed., Washington, 1896-1899, Vol. III, p. 602.