The returns to the presented colors show that it was hardest to get back to the presented yellow, easiest to get back to the presented blue, the averages (216 exp. each), being: Sec. To yellow, 1.67 " red, 1.61 " green, 1.58 " blue, 1.47 The facts as to blue and yellow shown by these four tables of averages may be expressed also in this way: If a blue square was shown, it was easier to change the blue memory image into the other colors, and also easier to get back the blue memory image after such changes, than if any other of the three colors was presented. If another color than blue was shown it was harder to change the memory image of that color to blue than to any of the other colors, and also harder to get back to the memory image of that color from blue than from any of the other three colors. If a yellow square was shown, it was harder to change the yellow memory image into the other colors, and also harder to get back the yellow memory image after such changes than if any other of the three colors was presented. If another color than yellow was shown, it was easier to change the memory image of that color to yellow than to any of the three other colors, and also easier to get back to the memory image of that color from the yellow than from any of the other three colors except red. If we combine _all_ the changes into a color (both changes from another presented color and returns to this color previously presented) we find that changes to green are hardest, to yellow easiest. The averages (for 432 exp. each) are, Sec. To green, 2.03 " blue, 1.99 " red, 1.97 " yellow, 1.92 The changes away from a color (both from this color previously presented and from this color to the other previously presented colors) show that it was hardest to get away from yellow, easiest to get away from blue, the averages (for 432 exp. each) being: Sec. From yellow, 2.06 " red, 2.02 " green, 1.94 " blue, 1.88 As for the subjects, all six found yellow the easiest to change into, one finding red equally easy. SUBJECTIVE.