[Footnote 94: Wollaston, _Philosophical Transactions, Royal Society_, 1810. In the same place Wollaston also describes and explains the creaking of the muscles. My attention was recently called to this work by Dr. W. Pascheles.--Cf. also Purkinje, _Prager medicin_. _Jahrbücher_, Bd. 6, Wien, 1820.] [Footnote 95: Similarly many external forces do not act at once on all parts of the earth, and the internal forces which produce deformations act at first immediately only upon limited parts. If the earth were a feeling being, the tides and other terrestrial events would provoke in it similar sensations to those of our movements. Perhaps the slight alterations of the altitude of the pole which are at present being studied are connected with the continual slight deformations of the central ellipsoid occasioned by seismical happenings.] [Footnote 96: For the popular explanation by unconscious inference the matter is extremely simple. We regard the railway carriage as vertical and unconsciously infer the inclination of the trees. Of course the opposite conclusion that we regard the trees as vertical and infer the inclination of the carriage, unfortunately, is equally clear on this theory.] [Footnote 97: It will be observed that my way of thinking and experimenting here is related to that which led Knight to the discovery and investigation of the geotropism of plants. _Philosophical Transactions_, January 9, 1806. The relations between vegetable and animal geotropism have been more recently investigated by J. Loeb.] [Footnote 98: This experiment is doubtless related to the galvanotropic experiment with the larvæ of frogs described ten years later by L. Hermann. Compare on this point my remarks in the _Anzeiger der Wiener Akademie_, 1886, No. 21. Recent experiments in galvanotropism are due to J. Loeb.] [Footnote 99: _Wiener Akad._, 6 November, 1873.] [Footnote 100: _Wiener Gesellschaft der Aerzte_, 14 November, 1874.] [Footnote 101: I have made a contribution to this last question in my _Analysis of the Sensations_, (1886), English translation, 1897.] [Footnote 102: In my _Grundlinien der Lehre von den Bewegungsempfindungen_, 1875, the matter occupying lines 4 to 13 of page 20 from below, which rests on an error, is, as I have also elsewhere remarked, to be stricken out. For another experiment related to that of Foucault, compare my _Mechanics_, p. 303.] [Footnote 103: _Anzeiger der Wiener Akad._, 30 December, 1875.] [Footnote 104: The experiment was specially interesting for me as I had already attempted in 1874, although with very little confidence and without success, to excite electromagnetically my own labyrinth through which I had caused a current to pass.]