G.  Two series. (1) V. farther up to F. 120, then symmetrical, and beyond F. 140, nearer center.  F. 140, V. 63. (2) V. much farther up to F. 120, then nearer center, but more nearly symmetrical than (1).  A complete series of second choices beginning at F. 40, V. slightly nearer center than F.

Analyzing results, we find the changed stamp, which has the interest of novelty, nearly always nearer the center than the unchanged.  This would indicate a balance of the mechanical type, in which the interest makes an object ‘heavier.’  The exceptions are in (a) four choices of D, G to F. 140, and in (b), D’s choice beyond F. 200, and G’s beyond F. 120.  The deviations are thus seen to be all of the same type:  for positions of F. near the center, when a mechanical choice would have brought V. still nearer [(a)], it is instead put farther away; for positions of F. far from the center, when a mechanical choice would have put V. still farther away [(b)], it is instead brought near.  The exceptions are thus fully accounted for by the demand for space-filling.

E.  Experiments on Depth.

The experiments on suggestion of depth in the third dimension were as follows.  It was desired to contrast two objects differing only with respect to the degree to which they expressed the third dimension.  Those objects that do express the third dimension are, in general, views down streets, colonnades, corridors, gates, etc., or, in landscape, deep valleys, vistas between trees, distant mountains, etc.  It is evident that representations of products of human handiwork would be less unnatural when isolated for experiment, and two pairs of pictures were accordingly prepared as follows:  There was drawn on a square of 80 mm. the picture of the mouth of a railway tunnel, closed tightly by an apparently massive door; and another picture of identical form and surroundings, but showing the rails entering at a slight curve, the deep blackness within, and the small circle of light at the farther end.  The second pair consisted of the gateway of a baronial castle, with heraldic bearings and closed iron-wrought doors; and the same gateway open, showing a flagged pavement and an open court with fountain beyond.  The perspective effect was heightened by all possible means for both pictures, and care was taken to have the contrast of black and white the same for each pair, so that to the half-shut eye, opened and closed forms seemed to have the same tone.

The subjects were directed to try to feel the third dimension as vividly as possible—­to project themselves down the vistas, as it were—­and then to arrange the squares in the most pleasing manner.  The experiments were made by A, M, S, H and D.  Not all made the same number of repetitions, but as their notes were unusually suggestive, I have made use of all the results, and shall quote the notes for the most part verbatim: