STUDIES FROM THE Yale Psychological Laboratory EDITED BY EDWARD W. SCRIPTURE, Ph.D. Instructor in Experimental Psychology Volume IV. 1896 CONTENTS. Reaction-time in abnormal conditions of the nervous system, by Alfred G. Nadler, M.D.,......... Researches on reaction-time, by E. W. Scripture, . . . Influence of the rate of change upon the perception of differences in pressure and weight, by C. E. Seashore, Ph.D., Weber’s law in illusions, by C. E. Seashore, Ph.D., . .. Researches on voluntary effort, by E. W. Scripture, New apparatus and methods, by E. W. Scripture, Elementary course in psychological measurements, by E. W Scripture,.............. Notes,................. Yai.e University, New Haven, Conn. i 12 27 62 69 76 89 140 I Price, Si. Obtainable at New Haven, Psychological Laboratory, 109 Elm Street; New York, Charles Scribner’s Sons, 153 Fifth Ave.; London, Williamsand Norgate, 14, Henrietta St., Covent Garden ; Berlin, Mayer & Müller, Markgrafen- Strasse 51 ; Leipzig, Bernhard Liebisch, Kurprinz-Strasse 6; Paris, Schleicher Frères, 15, Rue des Saintes-Pères ; Bologna, Pietro Virano, Piazza Galvani.