The interpretation of this difference may be made in accordance with the principles already laid down. The ideated and actual movements which favor the recurrence and persistence of an idea are, on grounds generally recognized in psychology, much more likely to occur and repeat themselves when the corresponding movements, or the same movements in completer form, have frequently been repeated in observation of the corresponding object. TABLE IX. 1 2 3 4 5 Indiv. Aver. 1st 2d 1st 2d 1st 2d 1st 2d 1st 2d 1st 2d I. 22.5 32.5 27 28 26.5 28 26.5 27.5 26 29 25.7 29.0 II. 4.5 43 9 29 3.5 38 0 43 17 44.5 6.8 39.5 III. 0 22 0 20.5 9.5 16.5 0 23.5 3.5 9.5 2.6 18.4 IV. 0 31 1 35.5 4.5 39 16.5 32.5 16 20.5 7.6 31.7 V. 24 52.5 41.5 40 12 53.5 22 55 22 50.5 24.3 50.3 VII. 1.5 52 0 48 0 54.5 0 50.5 0 46.5 0.3 50.3 VIII. 12 26 10 27.5 11.5 23.5 13.5 28.5 15.5 20 12.5 25.1 IX. 24 43.5 20 42 25 42.5 20.5 44.5 28 42.5 23.5 43.0 X. 9 45.5 19.5 30 11 33 12 38 14.5 30 13.2 35.3 XI. 12.5 35 23.5 29.5 1 49 2 44 10.5 52 9.9 41.9 11.00 38.30 15.15 33.00 10.45 37.75 11.30 38.70 15.30 34.50 12.64 36.45 VI.--Absent. From this point on the place of Miss H. (IV.) is taken by Mr. R. The members in each pair of objects in this group were not exposed simultaneously. 1st: refers to object first exposed. 2d: refers to object last exposed. General average: 1st, 12.64 sec.: 2d, 36.45 sec. What is here called ideated movement--by which is understood the idea of a change in spatial relations which accompanies a shifting of the attention or a change in the mental attitude, as distinguished from the sense of movements actually executed--was recognized as such by one of the subjects, who says: "When the two objects are before me I am conscious of what seem to be images of movement, or ideated movements, not actual movements." The same subject also finds the image of the object which had the longer exposure not only more vivid in the quality of the content, but more distinct in outline.