When it shall seem desirable to enlarge any school tax district by consolidating with it any adjacent territory or district, which may or may not be levying any special school tax, the county board of education may petition the county commission to call an election in all of the districts concerned, including the school tax district proposed to be enlarged to determine whether a special tax for a uniform rate and time shall be voted in each and every one of the districts. The proposed rate and time shall not be less than the maximum rate in any school tax district or the maximum time in any such district.