THE PEKCEPTION OF SPACE. (ll.) 197

spaces would be identified, not only as totals, but point for point. And the emphatic sensations that may momentarily occur imbedded in larger space-feelings not only play a part in conferring the maximum of reality upon those spaces that contain them, but they are the means of adding together spaces which can only be experienced in succession. If, wandering through the woods to-day by a new path, I find myself suddenly in a glade which affects my senses exactly as did another I reached last week at the end of a different walk, I believe the two identical affections to pre- sent the same persisting glade, and infer that I have attained it by two differing roads. The spaces walked over grow congruent by their extremities ; though apart from the one sensation those extremities give me, I should be under no necessity of connecting one walk with another at all. Now. the case in no whit differs when shorter movements are con- cerned. If, moving first one arm and then another, a blind child gets the same kind of sensation upon the hand, and gets it again as often as he repeats either process, he judges that he has touched the same object by both motions, and concludes that the motions terminate in a common place. From place to place marked in this way he moves, and adding the places moved through, one to another, he builds up his notion of the extent of the outer world. The seeing man's process is identical ; only his units, which may be suc- cessive bird's-eye views, are much larger. But the emphatic sensations that may interrupt a feeling of movement perform another function still. They lend their own scale of absolute magnitude to the movement. That part of the movement-feeling with which they coincide is equated in extent with them, they being more interesting than it. But as the magnitude of this part of the movement- feeling is immediately comparable in a more or less exact way with that of its remaining parts, the whole of the movement- space becomes measured in terms of the adventitious feeling in question. (d) Muscle-feelings versus Joint-feelings. The applications of this last principle are best seen in the Feelings of Movement which arise in joints. These feelings have been too much neglected hitherto, and in entering now somewhat minutely into their study I shall probably at the same time freshen the interest of the reader, which under the rather dry abstractions of the previous pages may pre- sumably have flagged.