Lotze still believes in an “absolute unity” as something prior to the world of reality, and he declares that “We cannot Know or Explain how this Absolute Unity is also Many” (Sec. XXI); and even if an unconscious being could be a Many-in-One, yet it could not, according to Lotze, generate consciousness (Sec. XXV). We do not believe that this problem is insolvable, and do not, as does Lotze, feel constrained to fall back on idealism. In fact, our position is so different from Lotze’s that in spite of the full recognition of his genius, we feel as much severed from him as if he belonged to ages long gone by. Mr. Conybeare’s translation is most certainly an invaluable work and is indispensable for any English student of Lotze’s philosophy. κρς. ON THE PERCEPTION OF SMALL DIFFERENCES, WITH SPECIAL REFERENCE TO THE EXTENT, FORCE, AND TIME OF MOVEMENT. By _George Stuart Fullerton_ and _James McKeen Cattell_. Philadelphia: University of Pennsylvania Press. 1892. Pp. 159. This volume of the Philosophical Series of Publications of the University of Pennsylvania gives an account of a large number of experiments made for the purpose of testing the perception of small differences of movement, of weight, and of light. The most noticeable conclusion arrived at by the authors, is that they cannot accept any of the received explanations of Weber’s law. They found from their experiments, by the method of estimated amount of difference, that “we tend to estimate the intensity of sensation as directly proportional to the intensity of the stimulus; consequently, in so far as any deduction concerning quantitative relations in sensation can be made from such estimation, the sensation increases as the stimulus and not as its logarithm,” thus invalidating Fechner’s law. The authors believe also that Weber’s law does not hold for the perception of movement, as they find that the error of observation usually increases “as the stimulus is taken greater but more slowly,” and that it is proportional to the square root of the stimulus. Accordingly, they substitute for Weber’s law the following: “The error of observation tends to increase as the square root of the magnitude, the increase being subject to variation, whose amount and cause must be determined for each special case.” It is proper to add, that Professor Fullerton gives only a qualified assent to these conclusions, on the grounds that mathematicians are not agreed as to the soundness of the theory upon which the law is based, and that the errors in question may not be independent errors. He considers, however, the results obtained by the authors “as sufficiently in accord with the laws to justify them in holding it tentatively, and subject to criticism.”