[15] The Expression of the Emotions, 1st ed., pp. 72, 69, 70.
[16] C. Féré, Sensation et Mouvement. Paris, 1887.
[17] Grundzüge der Physiologischen Psychologie, 2nd ed., (1880), Vol. ii, p. 437.
[18] "On the Temperature Sense," Mind, 1885.
[19] Rood, Modern Chromatics,(1879), pp. 181-187.
[20] Handbuch der Physiologischen Optik, 1st ed. (1867), pp. 318-319.
[21] Éléments de psychophysique. Paris, 1883.
[22] See the account given of these experiments in the Revue philosophique, 1887, Vol. i, p. 71, and Vol. ii, p. 180.
[23] Éléments de psychophysique, pp. 61, 69.
[24] In the particular case where we admit without restriction Weber's Law ΔE/E=const., integration gives S=C log. E/Q. Q being a constant. This is Fechner's "logarithmic law."