the separate existence of the high school began in  when the trustees decided "that in order to increase the efficiency of the columbia school a new class of a higher grade shall be formed at the commencement of the coming term to be taught by the principal" lower grades continued to be housed at columbia the trustees minutes of may   reflect the principals request "that a diploma be voted to miss etta a kilburn" and that "on motion a diploma was voted to miss kilburn the first graduate of the high school