In order to determine the place of greatest interference, the repeated figures were located in all possible positions, while the preceding and succeeding figures were left unaltered, so as to obviate any new influences which might result from a change of relations. There are fifteen possible variations of the series: _mabcdm_, _ambcdm_, _abmcdm_, _abcmdm_, _abcdmm_, etc. The following table, illustrative of the scheme _ambmcd_, will show the character of the results obtained. Only the numbers in which errors occur are here recorded, those figures which were incorrectly perceived being printed in heavy type. The dash is used when the location of the figure omitted is known, and the interrogation mark when the reply is doubtful. 8" 8" 5-1/2" 5-1/2" 5-1/2" 8" V. R. S. M. H. E. 708025 70625 76082 ..... 70825 7082-5 70285 958564 95584 ..... ..... 95864 985 ? 4 958-54 281845 281485 ..... 20861 28185 281-54 436392 43632 43636 436932 436924 43632 43632 526273 526723 5257 572673 52763 ..... 52623 940469 94069 940465 ..... 94069 94640 940-69 The interference may result in permutation, substitution, or inhibition. The latter two may take several forms; as, inhibition of identicals, of similars, of dissimilars, the location of the omitted figure being known or unknown; also, substitution of an identical, similar, or dissimilar figure which precedes or follows. The homogeneous series (540 tests) gives results as follows: HOMOGENEOUS SERIES Inhibition of Inhibition of Inhibition Identicals. Similars. due to Location. Location of the Spot Spot Spot Spot Spot Spot Identicals. Known Unknown Known Unknown Known Unknown