It should be placed a little toward the smaller building.

A colleague of the writer found, when this was first made public, that the pictures in his house had actually been hung in such a way as to allow for this illusion.

Whenever a picture was to be put up between two others of considerable difference of size, or between a door (large) and a window (small), it had actually been hung a little nearer to the smaller--toward the small picture or toward the window--and not in the true middle.
It is probable that interesting applications of this illusion may be discovered in aesthetics.

For wherever in drawing or painting it is wished to indicate to the observer that a point is midway between two lines of different lengths, we should find that the artist, in order to produce this effect most adequately, deviates a little from the true middle.

So in architecture, the effect of a contrast of masses often depends upon the sense of bilateral balance, symmetry, or equality, in which this visual error would naturally come into play.
Indeed, it is only necessary to recall to mind that one of the principal laws of aesthetic effect in the matter of right line proportion is the relation of "one to one," as it is called, or equal division, to see the wide sphere of application of this illusion.