each the theories which have meant most for the development of the science. The book includes forty-three authors from Anaxagoras to Wundt and about twenty pages are devoted to each. We find represented the important Greek philosophers and those of the Middle Ages, the English Associationists and the Scotch School. From the French Descartes, Bonnet, Condillac, and Maine de Biran have been selected. The Germans are very well represented. Of the living psychologists Hering, Mach, Stumpf and Wundt are included. As examples of the manner of selection we might add that James is represented by his chapters on the Stream of Consciousness, and on the Emotions; Stumpf by his Degrees of Tonal Fusion and Cause of Tonal Fusion; Mach by his Sensations as Elements and his Space Sensations; and Helmholtz by his Theory of Color Vision. A number of the translations are published for the first time.

The lectures which Angell (1) delivered at Union College have recently been published. They are in semi-popular form and give a sketch of the entire field of psychology, including abnormal, applied and animal psychology.

Hall's (7) lectures upon The Founders of Modern Psychology which were "designed to give a general idea of the personality, standpoint and achievement" of Zeller, Lotze, Fechner, Hartmann, Helmholtz and Wundt will no doubt be of interest to many.

The translation into German of Aristotle's (2) psychology will, apart from the fact of the cheap form in which it is published, hardly interest the English student, who already has several excellent translations in his own language.

REFERENCES

1. ANGELL, J. R. Chapters from Modern Psychology. New York: Longmans, Green, and Co., 1912. Pp. vi + 308.

2. ARISTOTLE. Über die Seele. Translated into German by Dr. Adolf Busse. Leipzig: Felix Meiner, 1911. Pp. xx + 120.

3. CALKINS, M. W. A First Book in Psychology. (3d rev. ed.) New York: Macmillan, 1912. Pp. xix + 426.

4. DESSOIR, M. Outlines of the History of Psychology. Translated by Donald Fisher. New York: Macmillan, 1912. Pp. xxix + 278.

5. DUNLAP, K. A System of Psychology. New York: Charles Scribner's Sons, 1912. Pp. xiv + 368.

6. ELSENHANS, T. Lehrbuch der Psychologie. Tübingen: Mohr (Paul Siebeck). 1912. Pp. xxiii + 434.

7. HALL, G. S. Founders of Modern Psychology. New York: D. Appleton and Co., 1912. Pp. vii + 471.

8. LEHMANN, A. Grundzüge der Psychophysiologie. Leipzig: O. R. Reisland, 1912,

Pp. x + 742.

9. NATORP, P. Allgemeine Psychologie nach kritischer Methode. Erstes Buch, Objekt und Methode der Psychologie. Tübingen: Mohr (Paul Siebeck), 1912. Pp. xii + 352.

10. RAND, B. The Classical Psychologists. Boston: Houghton Mifflin Company, 1912. Pp. xxi + 734.

II. WUNDT, W. An Introduction to Psychology. Translated from the second German Edition by Rudolph Pintner. New York: Macmillan, 1912. Pp. xi + 198.

APPARATUS

BY PROFESSOR C. E. SEASHORE

University of Iowa

The Cornell Laboratory (1) has set a good example in reporting detailed specifications for the following five pieces of apparatus. It is very desirable that the various laboratories should adopt the plan of describing fairly permanent pieces of apparatus apart from the report of the research.

Sound Localization Apparatus.-This apparatus consists essentially of a well-mounted and graduated curved arm which may carry a sounding apparatus such as a telephone receiver or a tuning fork, in any direction from the center of the head, under controlled conditions. It is built on excellent lines, but its use is limited. On the basis of years of experience with a perimeter (see PSYCHOL. Rev., 10, 64 ff.) the reviewer would suggest the following modifications to make the Cornell apparatus of more general use: (a) For the production of sound fusions, or phantom sounds, mount another arm to move in the same way and in the same plane as the present arm. (b) To facilitate measurement in the vertical direction, mount a third arm at the side moving at right angles to the line of the other two arms. (c) Take off the head rest which is a serious distraction and substitute a system of sighting for the alignment of the head. (d) Make the apparatus portable. (e) Convert it at will into a firstclass color perimeter by mounting a Helpach lantern for color stimulus in place of the sound stimulus.

Rhythm Interruptor. This provides for all the necessary control in the ordinary rhythm experiment, and would seem to be very serviceable. An electric phonograph motor is used to drive the apparatus. This is reported as having an error of .9 per cent., which is not accurate enough for the finest measurements, as some persons can perceive deviations of that amount. For the finest work in rhythm, the best available source of power and speed control

is a synchronous motor, which may have an error of less than .0008 of a second. Such a motor can of course be attached to this apparatus in place of the phonograph motor.

Rhythm-box Controller. This consists of a Stoelting rhythm-box equipped with a device for starting and stopping the metronome in the box noiselessly and with precision.

Rhythm Hammer.-This hammer may be used in setting up any desired pattern of rhythm. It is well adapted for demonstration purposes, and may be used for fine work if driven by a constant speed

motor.

Automatic Tuning-fork Hammer.—This hammer is designed to produce an accurate and controlled stroke and to dampen the fork with precision.

Brown (2) describes a method of measuring short intervals which could very easily be used in reaction time experiments in psychology. His measurement depends upon the principle that the time interval varies directly as the throw of a ballistic galvanometer which has been connected in a particular way through a Wheatstone bridge circuit during the interval. The method is capable of a sufficiently high degree of accuracy for ordinary reaction time experiments, and the apparatus could be built at a very reasonable cost.

Dunlap (3) gives an account of what seems to be a very serviceable laboratory pendulum that will swing for more than an hour with a high degree of accuracy. Full specifications for construction are given.

In the article in the British Journal (4) he discusses the advantage of working without the springs on the Hipp chronoscope, and reports the results of tests under these conditions.

Ferree (5) states that "the object of this apparatus is to add to the vertical campimeter the rotary features of the perimeter, and thus to allow investigation of every possible meridian of the retina with as much ease and precision as was possible with the old form of campimeter in the nasal meridian only, or at most, in the nasal and temporal meridians." For full description one must consult the original. To the reviewer it seems unfortunate that the apparatus was not built for operation on the surface of a hemisphere rather than on a plane surface.

Martin (6) has given us a useful manual for the quantitative use of faradic stimuli, from the point of view of the needs of the physiological laboratory.

Michotte (7) describes what seems to be a very excellent form of

a tachistoscope which is capable of accurate and very wide range of use. It may be employed as an ordinary shutter; two exposures may be made upon the same point of the retina under controllable conditions of time, space, and intensity; the exposed objects may be magnified; and the conditions of adaptation may be varied. It seems probable that all the important sources of error in apparatus for tachistoscopic experiments have here been eliminated. The instrument is made by Zimmerman in Leipzig.

REFERENCES

1. BENTLEY, M., BORING, E. G., and RUCKмICH, C. R. New Apparatus for Acoustical Experiments. Amer. J. of Psychol., 23, 509–516.

2. BROWN, F. C. An Electrical Method of Measuring Small Intervals of Time. Physical Review, 34, 452-458.

3. DUNLAP, K. A New Laboratory Pendulum. Psychol. Rev., 19, 240–245.

4. DUNLAP, K. The Hipp Chronoscope without Armature Springs. Brit. J. of Psychol., 5, 1-7.

5. FERREE, C. E. 449-453

Description of a Rotary Campimeter. Amer. J. of Psychol., 23,

6. MARTIN, E. G. The Measurement of Induction Shocks. New York: John Wiley & Sons, 1912. Pp. 117.

7. MICHOTTE, A. Description et fonctionnement d'un nouveau tachistoscope de comparaison. Arch. de psychol., 12, 1–13.

SPECIAL REVIEWS

DUNLAP'S SYSTEM OF PSYCHOLOGY

A System of Psychology. KNIGHT DUNLAP. New York: Charles Scribner's Sons, 1912. Pp. xiv+368.

Professor Dunlap has designed his book for semi-advanced students. He has desired to present a sketch, as systematic as possible, of the general field of psychology. It does not, however, seem that he has succeeded as well in presenting a connected series of facts as he might have done had he written a conventional textbook. It would perhaps describe the book better if one called it an introduction to a system of psychology, for the impression one receives is that of a collection of definitions. One finds very few references to experimental data. It was undoubtedly Dunlap's idea that such references would be out of place in a "system," but in consideration of the manner in which the book has actually been planned and the fact that the author ranks among the leading experimentalists, it is a question whether it would not have gained greatly in value if they had been more generally included.

The author believes that psychology should not at present be divorced from philosophic theories. This is undoubtedly true, but in introducing philosophy into a psychological treatise one must have constantly in mind the danger of wandering into fields no longer psychological. This is an error Dunlap has at times made, for example, when under perception he gives us a section upon the determination of perceptual truth and falsity, a subject which is only in place in a logical or epistemological treatise.

The definition of psychology adopted by the author reads as follows: "psychology is the study of experience: of the reference of experience to its content: of any direct reference it may have to a subject of experience: and of the content of experience in so far as it is directly related to experience." It will be seen from this that the author separates function from content. Whether or not in Dunlap's opinion this separation is justified by an analysis of consciousness is not clear.

Of the three elements of consciousness usually accepted, namely sensations, feelings and images, Dunlap rejects images as specific