FEB 11 , /g^ 



SCIENCE 



New Series. 

 Vol. XXI. No. a 



28. ^Io'^^^^Friday, February 10, 1905. 



Single Copies, 1.5 Cts. 

 Annual Subscription, 85.00. 





...Wood's ©ptical Novelties... 



The following novelties, devised and made by Professor R. W. Wood, of Johns Hopkins University, 

 afford inexpensive and striking illustrations of some of the most fundamental, and of some of the most 

 recondite, phenomena of light. 



S 25. Phase=Reversal Zone Plates illustrating diifraction and aiding in the explanation 



of the rectilinear propagation of light. (Phil. Mag., 45, p. 511.) . . . .Each $1.50 

 S 29. Dichromatic Prisms illustrating absorption coefficients. (Phys. Rev., 15, p. 121.) 



Each 1.75 



S 30. Cyanine Prisms with Attached Gratings illustrating anomalous dispersion and 



showing the disperf-ion curve. (Phil. Mag., 46, p. 380, Id. 1, p. 624.) . . Each 3.50 



S 31. Nitroso Screens absorbing visible actinic light while transmitting the ultra-violet. 



(Phil. Mag., 5, p, 257) Each 2.75 



S 32. Nitroso Screens with Cobalt Glass transmitting ultra-violet only. For spectrum 



photography and experiments in fluorescence. (Phil. Mag., 5, p. 257) . . . Each 3.25 



Descripiive Circular post-free. 



"The Scientific Shop" 



aUBERT B. PORTER 



Scientific Instruments 322 Dearborn St., Chicago 



A New Work by WILHELM WUNDT 



Physiological Psychology 



By WILHELM WUNDT. A translation of the 5th and wholly re- 

 written (1902-3) German Edition, by EDWAED B. TITCHENER, 

 Sage Professor of Psychology, Cornell University. With illustrations. 



In three volumes, Svo, Cloth. Vol.1. $3.00 net. (postage 15c.) 



" Wundt is probably the greatest psychologist of this generation. His psychological labor- 

 atory at Leipsic is famed throughout the world, and many of the larger universities in 

 diiFereut countries have their departments of experimental psychology manned by men 

 that have been with Wundt at Leipsic." — Post Graduate and Wooster Quarterly. 



THE MACMILLAN COMPANY, Publishers, 66 Fifth Ave., New Yoric 



