Due to its length, Mr. Jones' paper on sensitometry which was presented in part on three consecutive days at the Spring, 1931, Meeting of the Society at Hollywood, Calif., will likewise be published in the Journal in three issues. The following is the second of the three installments. The paper deals in a tutorial manner with the general subject of sensitometry, its theory and practice. The third installment will be published in the January, 1932, issue of the Journal.