ABSTRACT
It is easy to appreciate that by moving the touching finger along objects, the sequence in which the impressions of the object are presented becomes known; that this sequence shows itself to be independent of whether one feels with this or with that finger; that, furthermore, it is not a single-channeled, determined series, whose elements one must again and again traverse forward or backward in the same order so as to go from one to another—thus is no linear series, but rather a surface-like coexistence, or in Riemann’s terminology, a manifold ofthe second order.
