For the purpose of enabling the county board of any county in this state to employ in a profitable manner all persons who have heretofore been or may hereafter be sentenced to hard labor in the jail of the county, the board, or a majority of them, shall have power to designate the place where the persons so sentenced shall work, and to make all proper and needful regulations and provisions for the profitable employment of such convicts, and for their safe custody during such employment. The county jail is hereby declared to extend to any stone quarry, road or other place that shall be designated by the county board for the employment of such convicts.